United States

Department

of Agriculture

Forest Service

Rocky Mountain

Research Station

General Technical Report

RMRS-GTR-274

June 2012

R. Kasten Dumroese

Thomas D. Landis 

Tara Luna

Raising Native 

Plants in Nurseries: 

Basic Concepts
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Dumroese, R. Kasten; Landis, Thomas D.; Luna, Tara. 2012. Raising native plants in 

nurseries: basic concepts. Gen. Tech. Rep. RMRS-GTR-274. Fort Collins, CO: U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station. 84 p.

Abstract

Growing native plants can be fun, challenging, and rewarding. This booklet, particularly the 

first chapter that introduces important concepts, is for the novice who wants to start growing 

native plants as a hobby; however, it can also be helpful to someone with a bit more experience 

who is wondering about starting a nursery. The second chapter provides basic information 

about collecting, processing, storing, and treating seeds. Chapter three focuses on using 

seeds to grow plants in the field or in containers using simple but effective techniques. For 

those native plants that reproduce poorly from seeds, the fourth chapter describes how to 

start native plants from cuttings. The final chapter provides valuable information on how to 

successfully move native plants from the nursery and establish them in their final planting 

location. Several appendices expand on what has been presented in the chapters, with more 

details and specific information about growing a variety of native plants.

About the Authors

R. Kasten Dumroese is the USDA Forest Service National 

Nursery Specialist and a Research Plant Physiologist in the 

Rocky Mountain Research Station, Grassland, Shrubland, and 

Desert Ecosystems Program, Moscow, Idaho.

Thomas D. Landis retired from the USDA Forest Service as 

the National Nursery Specialist. Now living in Medford, Oregon, 

he consults with native plant nurseries.

Tara Luna is a botanist and ecologist working with native plant 

nurseries in the western United States and resides in East 

Glacier, Montana.

Acknowledgments

This General Technical Report is intended to supersede 

Raising Forest Tree Seedlings at Home: Simple Methods for 

Growing Conifers of the Pacific Northwest From Seeds, written 

by R.K. Dumroese, T.D. Landis, and D.L. Wenny in 1998 as 

Idaho Forest, Wildlife, and Range Experiment Station Contribution Number 860. We thank Randy Moench, Colorado State 

Forest Service, and Jim Borland, Denver Botanic Garden, for 

their thoughtful reviews of earlier drafts, and Jim Marin for 

graphic design and initial layout. To enhance this publication’s national impact, George Hernández graciously provided 

information for eastern species found in Appendix 6.1. We also 

thank the staff of Publishing Services at the Rocky Mountain 

Research Station. Funding was provided by the National Center 

for Reforestation, Nurseries, and Genetic Resources and the 

Rocky Mountain Research Station.
Contents

Chapter 1. Basic Concepts of Growing Native Plants . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 Factors That Limit Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Starting Your Own Nursery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2.1 Bareroot Nurseries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2.2 Container Nurseries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.3 Seeds and Other Propagules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.4 Crop Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1.4.1 Seedling Growth Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.4.1.1 Establishment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.4.1.2 Rapid Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.4.1.3 Hardening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

1.4.2 Crop Production Schedules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.4.3 Solar Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.5 The Right Plant for the Right Place . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

1.6 Additional Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Chapter 2. Obtaining and Preparing Seeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.1 Important Seed Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.1.1 Seed Dormancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

2.1.2 Seed Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

2.2 Purchasing Native Plant Seeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.3 Collecting Native Plant Seeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

2.3.1 Collecting Seeds and Fruits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.3.1.1 Conifer Cones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.3.1.2 Dry and Fleshy Fruits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2.3.1.3 Grasses and Forbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2.4 Handling Seeds and Fruits After Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.5 Seed Cleaning and Extraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.5.1 Cleaning Non-Dormant Seeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.5.2 Cleaning Dry Fruits, Capsules, and Seed Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.5.3 Cleaning Fleshy Fruits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.6 Storing Seeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

2.7 Seed Dormancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.7.1 Non-Dormant Seeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.7.2 Dormant Seeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.7.2.1 Internal Dormancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.7.2.2 External Dormancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.8 Seed Treatments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.8.1 Stratification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 

2.8.1.1 Naked Stratification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 

2.8.1.2 Sandwich Stratification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

2.8.2 Scarification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

2.8.2.1 Mechanical Scarification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

2.8.2.2 Hot Water Scarification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

i
2.9 Premature Germination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

2.10 Germination Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

2.11 Additional Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Chapter 3. Growing Plants From Seeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

3.1 The Importance of Quality Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

3.2 Growing Bareroot Seedlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

3.2.1 Nursery Site Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

3.2.2 Site Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

3.2.3 How to Grow Seedlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

3.2.3.1 Fertilizers: Organic vs. Synthetic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

3.2.3.2 Sowing and Germination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

3.2.3.3 Young Seedlings: Establishing Your Crop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

3.2.3.4 Watering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

3.2.3.5 Root Pruning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

3.2.4 Lifting, Handling, and Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

3.2.5 Transplanting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

3.2.6 Soil Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

3.3 Growing Container Seedlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.3.1 The Propagation Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.3.1.1 Growing Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

3.3.1.2 Containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

3.3.1.2.1 Filling Containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

3.3.2 Sowing and Germination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

3.3.2.1 Direct Sowing (20% of Species) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

3.3.2.2 Sowing Germinants (15% of Species) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

3.3.2.3 Transplanting Emergents (65% of Species) . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

3.3.3 Irrigation and Fertilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.3.3.1 Irrigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.3.3.2 Fertilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.3.3.2.1 Controlled-Release Fertilizers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

3.3.3.2.2 Fertigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

3.3.3.2.3 Seedling Growth Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

3.3.3.2.4 Sample Fertigation Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

3.3.4 Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3.3.5 Hardening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3.3.6 Pest Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3.3.7 Beneficial Microorganisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3.3.8 Harvesting, Handling, and Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3.3.9 Holding Seedlings Over . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3.3.10 Cleaning Containers Between Crops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3.4 Additional Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Chapter 4. Growing Plants From Cuttings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.1 Shoot Cuttings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.1.1 Hardwood Cuttings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.1.2 Softwood Cuttings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.1.3 Semi-Hardwood Cuttings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

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4.2 Collecting and Storing Shoot Cuttings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

4.2.1 Cutting Size, Labeling, and Temporary Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

4.2.2 Storing Cuttings at the Nursery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

4.3 Rooting Shoot Cuttings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

4.3.1 Rooting Hormones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

4.3.2 Rooting Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

4.3.3 Rooting Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

4.4 Transplanting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

4.5 Other Propagules used in Vegetative Propagation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

4.6 Post Transplanting Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

4.7 Additional Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Chapter 5. Outplanting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.1 Care During Outplanting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.2 Outplanting Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.3 Outplanting Tools and Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

5.4 Care After Outplanting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

5.4.1 Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

5.4.2 Fertilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

5.4.3 Weeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

5.4.4 Animal Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

5.5 Additional Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Appendix

6.1 Seed Characteristics of Some Common U.S. Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

6.1.1 Conifer Trees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

6.1.2 Deciduous Trees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.1.3 Woody Shrubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

6.1.4 Forbs (Wildflowers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

6.1.5 Grasses and Grass-Like Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

6.2 More Intensive Fertilization for Bareroot Seedlings: An Introduction . . . . . . . . . . . . . . . . . . . 74

6.2.1 Intensive Bareroot Fertilization for Soil With pH Less Than 6.0 . . . . . . . . . . . . . . . . . . 75

6.2.2 Intensive Bareroot Fertilization for Soil With pH Greater Than 6.0 . . . . . . . . . . . . . . . 76

6.2.3 Organic Fertilization of Bareroot Seedlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

6.3 Calculating the Number of Seeds to Sow Per Container Using a Hand-Held Calculator . . . 78

6.4 Soluble Fertilizer Chemicals that Provide Macronutrients for Custom Fertilizer 

Solutions for Container Seedlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.5 Calculating Parts per Million and More Intensive Fertilization for Container Seedlings . . . . 80

6.5.1 Fertilization of a Container Crop of Ponderosa Pine . . . . . . . . . . . . . . . . . . . . . . . . . . 81

6.6 Handy Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

iii
Trade names are used for the information and convenience of the reader and do not 

imply endorsement or preferential treatment by the U.S. Department of Agriculture.

Nomenclature for scientific names follows the U.S. Department of Agriculture, Natural 

Resources Conservation Service PLANTS (Plant List of Accepted Nomenclature, 

Taxonomy, and Symbols) database (2011) at http://plants.usda.gov.

Pesticide Precautionary Statement

This publication reports research involving pesticides. It does not 

contain recommendations for their use, nor does it imply that the uses 

discussed here have been registered. All uses of pesticides must be 

registered by appropriate State and/or Federal agencies before they 

can be recommended.

CAUTION: Pesticides can be injurious to humans, domestic animals, 

desirable plants, and fish or other wildlife—if they are not handled or 

applied properly. Use all pesticides selectively and carefully. Follow 

recommended practices for the disposal of surplus pesticides and 

pesticide containers.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 1

Chapter 1—Should I Grow My Own Native Plants?

Chapter 1. Basic Concepts of 

Growing Native Plants

This booklet was written for the novice who wants to 

grow native plants and may also wonder what is involved 

in starting a nursery. If you think that operating your own 

native plant nursery as a business is your calling, then 

this manual, and particularly this first chapter, can help 

you move forward. If, however, you plan to grow native 

plants for fun, perhaps for use around your home or as a 

science fair project, this manual can still give you the basic 

information required for you to be successful, and all the 

concepts provided in this chapter are still applicable. 

Much has been written about growing trees and commercial conifers in particular, and the same basic principles 

can be used to grow native shrubs, forbs, ferns, wildflowers, 

and grasses. Growing native plants involves a unique combination of science and art. Although this book explains the 

basic science of growing native plants, a good grower must 

also have skills that can be acquired only through innate 

ability or experience. Collectively, these special skills are 

what is commonly known as having a “green thumb.”

1.1 Factors That Limit Growth

To grow plants well, it is important to understand what 

limits growth. Ecologists refer to this as the concept of 

limiting factors and it can be helpful to people starting a 

native plant nursery. It states that, although a biological 

process such as growth is affected by several factors, the 

rate of that process is controlled by the factor that is most 

limiting. If we apply this concept to nursery culture, we 

can identify those environmental factors that would be 

potentially limiting to plant growth and design our nursery to overcome them (Figure 1.1A). For example, water 

is often limiting so we supply plenty of quality water 

through irrigation. The concept of limiting factors is easy 

to demonstrate; when fertilizer was provided to spruce 

seedlings, their growth increased significantly compared 

with those plants grown without fertilizer (Figure 1.1B), 

indicating that the lack of fertilizer was limiting growth.

Figure 1.1—Many environmental factors can limit plant growth 

(A), and we can overcome most of those limitations in nurseries. 

For example, supplying fertilizers greatly increases plant growth 

(B). Typically, more than one factor is limiting so their effects 

can be sequential and cumulative. In this example (C), water 

is the most limiting factor but once we supply irrigation then 

nitrogen becomes most limiting, and so on.

A

B

C
2 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Note that plant growth is usually limited by more than 

one factor and that these limiting factors are sequential—as 

soon as you satisfy one, another one becomes limiting. 

Only when we overcome all the environmental factors that 

limit plant growth can we achieve their maximum growth 

(Figure 1.1C). 

By managing growth-limiting factors we can develop 

an environment suitable for growing plants, our “propagation environment”; this is any location that has been 

modified for the purpose of growing plants. Propagation 

environments can be as simple as a garden plot where 

water and fertilizer are applied, or as complex as high-tech 

greenhouses that also modify light, temperature, humidity, 

and carbon dioxide levels.

1.2 Starting Your Own Nursery 

If you decide to start a native plant nursery, the first 

question to answer is whether it should be a bareroot or 

container facility. Limiting factors must be considered 

when deciding between a bareroot or container nursery, 

and often, the lack of a suitable nursery soil is the critical 

factor. Your general climate is also critical because greenhouses used to grow seedlings in containers are best at 

high latitudes or elevations where extremely short growing seasons make bareroot production impractical. Under 

some circumstances, the most appropriate nursery includes 

bareroot and container capabilities.

1.2.1 Bareroot Nurseries

Bareroot nursery plants are, as their name implies, harvested and outplanted (planted at their final destination) 

without any soil around their roots (Figure 1.2A). They 

are grown in open fields in native soil (Figure 1.2B), and 

consequently, the quality of the soil and water is critical. 

The types of bareroot seedlings (stocktypes) include those 

grown from seeds or rooted cuttings. Sometimes these 

seedlings are transplanted, physically removed from their 

original nursery bed, and moved to a different bed for 

an additional 1 or 2 years’ growth. In bareroot nurseries, 

plant growth rate is controlled by local climate because 

it determines the length of the growing season. Although 

any good garden soil can be used to produce bareroot 

seedlings, large, quality bareroot nursery sites are difficult to find in convenient locations, and good agricultural 

land is often expensive. Due to land and equipment costs, 

a considerable capital investment is usually required to 

develop a bareroot nursery of any size. However, compared 

to container nurseries, energy requirements and operating 

expenses are relatively low. 

Figure 1.2—Bareroot seedlings are stored and shipped for 

outplanting without soil around the root system (A). They are 

grown in outdoor nursery “beds” in native soil and are exposed 

to local weather conditions (B).

A

B

Chapter 1—Should I Grow My Own Native Plants?
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 3

1.2.2 Container Nurseries

Most native plants are grown in containers filled with 

an artificial substrate (growing medium) rather than soil 

(Figure 1.3A). In colder climates, plants are grown in a 

controlled environment, such as a greenhouse, where all 

growth-limiting factors can be controlled (Figure 1.3B), 

whereas in milder climates, container plants can be grown 

in outdoor growing areas. Because the volume of growing 

medium is relatively small, the roots bind the medium into 

a cohesive “plug” by the time they are harvested (Figure 

1.3C). Although they are also called “containerized,” 

“container-grown,” or “plug” seedlings, we prefer the term 

“container plants” because it is simple and definitive.

Container nurseries can be located on land with low 

agricultural value that would be unsuitable for bareroot 

seedling production. Fully controlled greenhouses require 

expensive structures and environmental controls, but open 

growing compounds are much less costly. Because container seedlings are grown at high densities, considerably 

less land is required than would be needed to produce a 

similar number of bareroot seedlings. Container plants 

can have high growth rates, especially in fully controlled 

environments, and so many crops can be produced in one 

growing season. 

Many things must be considered when deciding whether 

to start a bareroot or container nursery. It is helpful to list the 

various considerations side-by-side for ease of comparison 

(Table 1.1).

A

Figure 1.3—Container plants are grown in artificial growing 

media (that is, not native soil) in some type of special propagation 

container (A), and raised in a propagation environment designed 

to minimize factors that potentially limit growth (B). By the end 

of the growing season, container plants are harvested with the 

root system and growing media forming a “plug” (C).

B

C

Chapter 1—Should I Grow My Own Native Plants?
4 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

1.3 Seeds and Other Propagules

A “propagule” is any plant part that can be used to 

produce another plant. These are typically either seeds 

(sexual propagation) or cuttings (asexual or vegetative 

propagation). To determine which type of propagule 

would be most efficient, you should become familiar 

with the life cycle of the plants that you wish to grow 

and how they reproduce in nature. For example, common snowberry produces abundant white fruits (Figure 

1.4A), but the small seeds (Figure 1.4B) do not germinate 

reliably. Therefore, native plant nurseries usually propagate this species from another type of propagule—stem 

cuttings, a form of vegetative propagation (Figure 1.4C). 

Many native plants do not produce a reliable crop of 

viable seeds every season, which is another reason that 

growers sometimes prefer to propagate from cuttings. 

The rooting ability of cuttings also varies with the time 

of the year, so growers must collect cuttings carefully at 

the proper season. Some species can be propagated from 

either seeds or cuttings. Quaking aspen seeds are very small 

and don’t store well, but this species does produce root 

sprouts, which can be collected and used as propagules 

(Figure 1.4D). Some plants with branches that grow 

low along the ground naturally root into the soil, so 

each branch section with roots can be a propagule—a 

propagation method called layering (Figure 1.4E). Many 

grasses and other grass-like plants have extensive root 

masses that can be divided into propagules (Figure 1.4F). 

If the native plant you want to grow produces bulbs, the 

bulblets that form naturally around the perimeter are 

potential propagules (Figure 1.4G). Other natives, such 

Table 1.1—Many factors should be considered when deciding whether to start a bareroot or container nursery.

Factor Container Nursery Bareroot Nursery

Land Requirement Less land needed More land needed

Soil Quality Not important because artificial Critical—sandy loams are preferred

growing media are used

Water Quantity Lesser amounts required Greater amounts required

Water Quality Good water is desirable but some Good water is critical

problems can be chemically corrected

Propagation Structures Depends on location, size, None

and complexity of the nursery

Equipment Depends on size and complexity of Tractors and specialized equipment

the nursery for sowing and harvesting

Duration of Crop Cycle 4 to 12 months to several years 1 to 3 years

depending on container size

Crop Storage and Transportation Greater volume required Lesser volume required

Plant Handling Roots are protected in plug Roots are exposed and are often

treated for additional protection

Season Seedlings Can Be Outplanted Year-round if soil moisture is good Spring or sometimes Fall

as woodland strawberry, produce stolons, which are 

specialized horizontal stems that produce new shoots 

and roots that can be used as propagules (Figure 1.4H). 

Seed (sexual) propagation will be discussed in Chapter 

3 and vegetative (asexual or cutting) propagation in 

Chapter 4. 

When collecting or purchasing propagules, the sex and 

genetics of the resulting plants must be considered. It is 

important to consider where seedlings will be planted 

before you begin to grow them. Native plants are adapted 

to their local growing conditions so it is usually best to 

collect seeds or cuttings from plants growing near the 

eventual outplanting site. This is important because moving 

a plant from one environment to another induces stress. 

Often the result is poor growth or even death. In addition, 

collecting propagules from a variety of individual plants 

ensures that the genetic diversity of the resulting nursery 

plants represents the original population of plants (see 

Chapter 2 for more information). In addition, plants that 

reproduce sexually (through flowering) obtain a mixture 

of genetic characteristics in their offspring, so each new 

plant will appear slightly different from its parents and 

each other (Figure 1.5). About 15% of native plant species 

are, however, dioecious, which means that plants are either 

male or female. This is important for species that are often 

propagated by cuttings, such as willows and cottonwoods, 

because taking cuttings from a single plant means that all 

new plants will be the same sex and have exactly the same 

genetics as the source plant; so because sexual and genetic 

diversity are desired, it is even more important to collect a 

few propagules from a large population of source plants.

Chapter 1—Should I Grow My Own Native Plants?
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 5

A

B

C

Figure 1.4—Types of propagules used to grow native plants 

include fruits (A) containing seeds (B), stem cuttings (C); continued 

on next page. 

Chapter 1—Should I Grow My Own Native Plants?
6 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

D G

E

H

F

Chapter 1—Should I Grow My Own Native Plants?

Figure 1.4—(Continued) Types of propagules used to grow native plants include root sprouts (D), layers (E), divisions (F), bulblets 

(G), and stolons (H).
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 7

1.4 Crop Scheduling

Once the best propagation technique has been identified, 

then the grower must do some planning and consider several different factors (Figure 1.6). Species characteristics, 

genetic variability, and availability of propagules were 

discussed in the previous section, and now we’ll cover crop 

scheduling. The final cost of producing a crop depends on 

all these factors but especially the choice of propagation 

method—plants propagated from seeds are always less 

expensive to produce than those from cuttings. 

Native plant growth and development, whether in nurseries 

or in the wild, is controlled by two factors: genetics and environment. Genetics are predetermined but, as we discussed 

earlier, you can control the propagation environment and 

minimize the effects of growth-limiting factors. All native 

plants follow a typical annual growth cycle, which begins 

when seeds germinate or seedlings resume shoot growth in 

early spring and continues until the plants become dormant 

in the fall. For nursery planning purposes, plant growth 

and development during the year can be divided into three 

Figure 1.5—Plants propagated from seeds may look different from their 

parents and their siblings because they contain a mixture of the genetic 

characteristics of each parent. Conversely, vegetative cutting propagation 

produces exact duplicates of the parent plant (“clones”). 

Figure 1.6—A successful native plant nursery is based on proper 

planning and many factors must be considered.

Chapter 1—Should I Grow My Own Native Plants?
8 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

consecutive growth phases: establishment, rapid growth, 

and hardening. Because cultural objectives are different 

for each phase, the growing environment and perhaps even 

the type of propagation structure may be different. The 

amount of time required for each of these growth phases 

varies depending on species, the propagule collection 

location (that is, the “seed source”), type of propagation 

environment, and cultural practices. Nursery managers use 

growth data from previous crops to estimate the duration 

of each phase and total length of the crop cycle.

1.4.1 Seedling Growth Phases

1.4.1.1 Establishment—In the case of seed propagation, the establishment phase begins when seeds are sown, 

continues through seed germination and emergence, and 

generally ends when the young seedlings develop true 

leaves. For vegetative propagation, the phase begins when 

the cuttings are struck into the container and ends when 

cuttings have rooted.

1.4.1.2 Rapid Growth—The rapid growth phase is sonamed because it is during this period that young nursery 

plants increase rapidly in size; in general, most of this 

increase in biomass is shoot tissue with relatively less root 

growth—some native plants, especially those adapted to 

harsh, dry sites, may do just the opposite, growing more 

roots than shoots . With seedlings, this phase begins after 

the cotyledon stage when the new shoot begins to grow 

at an accelerated rate and ends when plants have reached 

their target size.

1.4.1.3 Hardening—During the hardening phase, 

plants divert energy from shoot growth to stem diameter 

and root growth, and gradually become conditioned to 

withstand cold temperatures and the rigors of harvesting, 

shipping, and outplanting. In general, the cultural objective 

is to stop shoot growth, initiate development of a terminal 

bud in determinate species, and improve the plant’s tolerance to colder temperatures. 

1.4.2 Crop Production Schedules

The first and most long-term type of growing schedule 

is the crop production schedule, which is designed to 

help nursery managers visualize “the big picture.” These 

schedules typically are designed on a month-by-month 

time scale, cover at least 1 year, and include all phases 

of nursery production from crop planning to outplanting 

(Figure 1.7). Many nursery customers fail to appreciate 

how long it really takes to grow native plants crop, 

so crop production schedules are particularly useful for 

explaining all the various steps in the nursery process and 

the time involved. For example, a crop production schedule will illustrate that it will be necessary to ship seeds 

to the nursery several months prior to sowing, especially 

if germination tests and presowing seed treatments are 

necessary. These growing schedules are also useful in illustrating how different seedling stocktypes are produced, 

the time required to grow them, and when they would be 

available for outplanting.

1.4.3 Solar Timing 

Because of seasonal changes in the Temperate Zone, 

native plant crops are usually scheduled around the solar 

cycle (Figure 1.8). Both light intensity and daylength 

vary considerably during the year, so nursery managers plan their crops around the summer solstice to take 

full advantage of available sunlight. This is particularly 

critical for container nurseries that grow two crops per 

season. The first crop must be sown very early so that 

they can be large enough to move out of the greenhouse 

in time to allow plenty of sunlight for the second crop. 

Planning around the solar calendar also ensures that 

crops perceive the naturally shortening daylengths that 

queue them to prepare for winter. 

1.5 The Right Plant for the Right Place 

Although many people think that all plants of the same 

species are alike, they can be very different. We already 

discussed that plants can have different genes, which means 

they may have different morphology (how they look) and 

physiology (how they function). 

The best nursery stock has the proper morphological 

characteristics (such as height, stem diameter, and root 

volume) and physiological characteristics (such as dormancy 

status and cold hardiness) to have maximum survival and 

growth for a particular outplanting site. Seedlings being 

grown for a very dry place need thicker stem diameters, 

shorter shoots, and more roots than those being grown 

for a very moist place. Seedlings being grown for a very 

mountainous site must survive colder temperatures than 

seedlings being grown for valley locations. Trees for urban 

landscapes or orchards can be quite large with a large ball 

of soil around the roots because they will have better care 

after planting. The type of tool used to plant the seedlings 

will also affect how the seedlings must look in the nursery. 

Remember, before starting your crop, it is always important 

to consider where the plants will be outplanted to ensure 

they are adapted to the environment, the conditions on the 

planting site, and the type of planting tool.

Chapter 1—Should I Grow My Own Native Plants?
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 9

Figure 1.7—Crop production schedules give a chronological view of the necessary steps to produce a native plant crop, and how 

long it takes to complete each of those steps. Schedules are useful planning aids for nursery managers as well as their customers. 

Chapter 1—Should I Grow My Own Native Plants?
10 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

1.6 Additional Reading 

Landis T.D.; Tinus, R.W.; Barnett, J.P. 1999. The container tree nursery 

manual. Volume 6, Seedling propagation. Agric. Handb. 674. Washington, DC: U.S. Department of Agriculture, Forest Service. 167 p.

Landis, T.D.; Tinus, R.W.; McDonald, S.E.; Barnett, J.P. 1994. The 

container tree nursery manual. Volume 1, Nursery planning, 

Figure 1.8—Native plant crops should be scheduled around the annual solar 

cycle to take advantage of available sunlight; this is especially important for 

nurseries that plan to grow two crops each year.

Chapter 1—Should I Grow My Own Native Plants?

development, and management. Agric. Handb. 674. Washington, 

DC: U.S. Department of Agriculture, Forest Service. 188 p.

Wilkinson, K.M.; Landis, T.D. 2008. Planning a native plant nursery. 

In: Dumroese, R.K.; Luna, T.; Landis, T.D., eds. Nursery manual 

for native plants: a guide for tribal nurseries. Volume 1, Nursery 

management. Agric. Handb. 730. Washington, DC: U.S. Department 

of Agriculture, Forest Service: 2-13.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 11

Chapter 2. Obtaining and 

Preparing Seeds

The process of growing any native plant begins with 

procuring a supply of high quality seeds or other propagules. In Chapter 1, we talked about the various types of 

native plant propagules, and now, we will discuss how to 

find and process seeds to get you ready for your first crop. 

2.1 Important Seed Concepts 

Before collecting or buying any native plant seeds, you 

should understand a few critical concepts.

2.1.1 Seed Dormancy 

Although native plant seed can be categorized in many 

ways, its ability to germinate promptly is the most important from a grower’s standpoint. This seed characteristic 

is known as dormancy, and for our purposes, we’ll discuss 

non-dormant and dormant seeds. Non-dormant seeds are 

those that will sprout in a relatively short time—a few days, 

weeks, months but generally less than 1 year—without any 

special treatments. Examples include aspen, willow, and 

asters. Non-dormant seeds do not require any pre-sowing 

treatment other than soaking in water, and they are usually sown in the nursery soon after collection. Storage and 

handling of non-dormant seeds is critical because they must 

be kept moist. Temporary storage should be in a shaded, 

cool location. Large seeded, non-dormant seeds, such as 

acorns and nuts, must be kept fully moist by keeping them 

in trays under damp burlap bags or in plastic bags filled 

with moist sand or peat moss. Just prior to sowing, seeds 

are usually soaked in water for a few hours to a few days, 

depending on species. 

Dormant seeds require some sort of pre-sowing treatment, but store easily for long periods and can tolerate 

drying. Most conifers and many other native species fall 

into this category. Pre-sowing treatments to overcome 

seed dormancy will be discussed later in Section 2.8, Seed 

Treatments. Dormant seeds retain viability for periods 

longer than a year and can be dried to low seed moisture 

levels and stored under lower temperatures. 

2.1.2 Seed Source 

Plants are genetically adapted to their environment, and 

this adaptation is known as “seed source” in nursery jargon. If you plan to collect seeds locally, grow plants, and 

outplant them in the same climatic region, then your plants 

will be adapted and seed source isn’t critically important. 

If you purchase seeds, however, then you must consider 

where they were collected. 

Collecting seeds from a wide genetic base fosters a 

more diverse gene pool at the outplanting site. This can 

protect a planting against unforeseen biological and environmental stresses, and it also protects against potential 

genetic problems in future generations. For restoration and 

conservation projects, maintaining genetic diversity is a 

key project objective.

2.2 Purchasing Native Plant Seeds

If you need a small quantity of seeds or don’t have the 

time or resources to spend collecting your own, purchasing 

from a seed dealer may be more appropriate. 

Seeds for many native plants are available from seed 

collectors or seed dealers. Seeds are generally listed by 

common or scientific name, and it only makes sense that 

local seed vendors will more likely have the species that 

you are looking for. Finding the proper seed source is often 

more difficult. It’s a good idea to ask the seed dealer which 

seed sources of a particular species they have in stock, 

rather than specify which source you’re looking for. Some 

unscrupulous dealers always seem to have whatever source 

you need if they want to make a sale badly enough. To find 

reputable seed dealers in your area, call some local native 

plant nurseries or your local native plant society.

2.3 Collecting Native Plant Seeds 

Collecting seeds may be appropriate if you want seeds 

from a specific location or from specific plants. Just like 

people, plants of a particular species come in different 

shapes and sizes and, young plants usually resemble their 

parents. Therefore, only collect seeds from healthy and 

vigorous plants—ones that look like you want your 

plants to look. It may be easy to collect seeds from low 

growing plants or trees with limbs close to the ground, 

but this growth form may be genetic. So, with forest trees, 

especially those that are being grown for timber purposes, 

avoid trees that are forked, crooked, or have excessively 

large limbs. 

Before starting any seed collection, learn as much as you 

can about the ecology of the plant species. Some seeds are 

large and easy to collect while others will require special 

procedures or equipment. Annual plants, and perennial 

grasses and forbs, produce some seeds every year but the 

seed crops of perennial woody plants, such as shrubs and 

trees, can vary considerably from year to year. For example, 

trees like aspen produce seeds in 1 year, but others like 

pines and oaks can take 2 years or more to produce seeds. 

Chapter 2—Obtaining and Preparing Seeds
12 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

For an example of why it’s important to know the biology and ecology of a native plant species, let’s consider the 

oaks. Oaks can be divided into two groups: the “white” 

oaks, which produce acorns in one year and the “red” oaks, 

which take two years. In southern Oregon, two oak species 

grow on the same site. California black oaks (red oak group) 

have large acorns that are easy to collect (Figure 2.1A), 

but this species takes 2 years to produce seeds and only 

have abundant seed crops every 8 years or so. In contrast, 

Oregon white oaks (white oak group) produce acorns in 

a single year. By knowing the biology of this species, the 

location of a seed crop can be predicted by observing the 

abundance of the female flowers on second year twigs 

(Figure 2.1B).

2.3.1 Collecting Seeds and Fruits

Native plants produce a wide variety of seeds and fruits 

that often need to be cleaned and processed before sowing. 

The process for each species is very different so we won’t 

attempt to cover all species here, but we will give some 

general examples. 

2.3.1.1 Conifer Cones—Conifer fruits are woody cones 

that contain many hard-coated, winged seeds (Figure 2.2). 

Most conifers do not produce abundant cone crops every 

year, and the frequency depends on the species (Table 2.1). 

Native Plant Seed Collection Guidelines

•	 Always ask permission to collectseedsfrom private

lands, and don’t collect from public lands without a 

permit.

•	 Be absolutely certain of the positive identification

of plant species. If in doubt, collect and press a 

specimen for identification.

•	 Collect a few seeds from as many individual plants

of the species as possible. A good rule of thumb is 

to collect from at least 30 individuals.

•	 Try to collect the same amount of seeds from each

plant; no one plant should be over-represented in 

the collection. 

•	 If you are collecting seeds from a different location from where you will be outplanting your crop, 

try to select an area with similar elevation, aspect 

(north, south, east, west), and soil type.

•	 Leave enough seeds as a food source for animals

and to ensure the natural reproduction of the plants.

•	 Avoid soil disturbance and plant damage while collecting seeds, especially in fragile habitats.

•	 If possible, leave an area to rest for at least two

growing seasons between collections. Keep in 

mind that longer periods may be needed for some 

plant species.

•	 To prevent possible contamination of your seeds,

avoid weed infested areas if possible.

Figure 2.1—Oak acorns vary in the time they take to mature 

and how long they can be stored. Acorns of California black 

oak (A) take 2 years to mature but can be stored for several 

years. Future seed crops can be predicted by observing the 

small female flowers on twigs (B). 

A

B

Chapter 2—Obtaining and Preparing Seeds
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 13

Generally, cones at lower elevations are ready first, ripening gradually at higher elevations. Start checking potential 

trees in early summer at low elevations or mid summer for 

higher elevations.

Because seeds develop gradually in cones, it is difficult 

for a beginner to determine when it’s time to harvest them. 

In nature, most cones dry out until the seed scales open 

and the winged seeds blow away in the wind. So, the 

challenge is to harvest cones when seeds are mature, but 

before the cones dry too much and release the seeds. Pine 

cones change color from green or purple to yellowish-green 

to tan as the cone dries and the seeds mature. This change 

occurs gradually and is not a perfect guide to seed maturity, 

and often seeds are mature before the cone changes color. 

To really tell if conifer seeds are mature, you’ll need 

to cut the cone in half and check. Cones can be cut with 

a machete or hatchet. Cut cones lengthwise to expose 

seeds of Douglas-fir, pine, hemlock, spruce, and larch 

(Figure 2.3). Cones of true firs (noble, grand, balsam, 

and others) are cut a little different; slice the cones 

lengthwise about 1⁄2 inch to one side of the cone’s core 

Figure 2.2—Conifer cones are actually woody fruits that 

contain winged seeds.

Table 2.1—Four common conifers of the western U.S. and the years between good 

cone crops. 

Common name Scientific name Cone cycle (years)

Grand fir Abies grandis 2 to 3

Colorado (blue) spruce Picea pungens 1 to 3

Ponderosa pine Pinus ponderosa 2 to 5

Rocky Mt. Douglas-fir Pseudotsuga menziessii var. glauca 2 to 11

Figure 2.3—Conifer cones 

can be checked for filled 

seeds by cutting them in 

half. For Douglas-fir, pine, 

hemlock, and spruce, cut 

the cones exactly through 

the middle (left). For true 

firs, cut cones lengthwise 

about 1⁄2 inch to one side 

of the cone’s core (middle). 

For western redcedar and 

northern white-cedar, cut the 

cones widthwise just below 

the center of the cone (right).

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14 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

to ensure cutting through seeds. For western redcedar, incense-cedar, and arborvitae, cut the cone 

widthwise just below the center of the cone. 

Inspect the cut seeds on the cone faces with a 

hand lens to evaluate seed maturity (Figure 2.4A). 

Mature seeds have embryos that fill 90% or more 

of the embryo cavity (Figure 2.4B), and the material 

around the embryo is whitish and firm with a texture 

like coconut (Figure 2.4C). Cones can be harvested 

earlier, when embryos fill 75 to 90% of the cavity, 

but then you will have to after-ripen the cones for 2 

to 6 weeks (see Section 2.7.2.1, Internal Dormancy).

Based on the number of filled seeds per cone, you 

can determine how many cones you will need to 

collect. Cones can be collected with pole pruners or 

by climbing the trees, but climbing should generally 

be left to experts. Squirrels begin cutting cones and 

caching them around the bases of trees at about the 

time that seeds mature, so the easiest harvesting is 

to steal a few cones from a cache but make sure you 

leave some for the squirrel. Place cones in burlap or 

nylon screen sacks, and don’t contaminate your cones 

with needles, branches, and dirt that could introduce 

damaging molds. Cones have a high moisture content 

so fill sacks only half full to allow for air circulation 

and cone expansion during drying. Never toss or 

drop a bag of cones. Label each sack immediately 

with species, elevation, collection location, date, 

and any other pertinent information. Store sacks on 

open racks in dry, well-ventilated shelters, such as 

open-sided sheds or well-ventilated barn lofts. You 

may also hang sacks from rafters. Either way, sacks 

should be separated to permit good air circulation. 

Stored this way, cones will dry gradually with a 

minimum of overheating and mold damage. Check 

cones often and inspect them for mold. If mold is 

present, rearrange sacks to improve air circulation. 

If you picked cones with mature seeds, cones should 

dry satisfactorily in a few days, depending on the 

weather. If you picked green cones, it may take a 

few weeks or months for seeds to finally mature.

Some pines, such as lodgepole, knobcone, and 

jack, have cones that require heating before they 

will open. Here’s an easy way to open them. Put cones into 

a burlap bag and immerse the bag into very hot water 

(about 180 °F) for 30 seconds to one minute. Remove the 

bag, dump the cones onto a screen-bottomed tray, and place 

them in a warm location. The hot water softens the resins 

that keep the cones closed. As the cones dry, the scales 

pull open and you can extract the seeds.

Figure 2.4—The cut faces of conifer cones (A) can 

be inspected with a hand lens to evaluate seed 

maturity. The embryo (undeveloped seedling) in a 

mature conifer seed should almost fill the cavity (B). 

The embryo and megagometophyte (storage tissue) 

should be white and have a firm texture like coconut 

meat (C) (courtesy of L.E. Manning, Canadian Forest 

Service). 

A

B

C

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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 15

2.3.1.2 Dry and Fleshy Fruits—Dry fruits are those 

that are woody or papery at maturity and examples are 

hazel nuts (Figure 2.5A) and capsules (Figure 2.5B). 

Some dry fruits will split open at maturity. You will need 

to harvest these just before the fruits begin to split open 

and seeds disperse. Other dry fruits have structures where 

both the fruit and seed are fused together and do not split 

open at maturity. Dry fruits can be collected like cones. 

Nuts and acorns can be harvested after they drop from the 

tree as long as they are handled and cleaned immediately 

after collection (described below).

Fleshy fruits are those usually comprised of three layers: 

the skin, the often fleshy middle, and the membranous or 

stony inner layer (Figure 2.6). Depending on species, fleshy 

fruits can contain many seeds per fruit or they can bear a 

tough, stony pit that encloses only one seed. Therefore, the 

amount of fruits you have to harvest to obtain a desired 

number of seeds will vary greatly from species to species. 

When collecting and handling fleshy fruits, it is important 

to keep them cool and out of direct sun. Heat buildup and 

subsequent fermentation can damage the seeds inside the 

fruits. It is also important not to let the fruits dry out, because this can make cleaning more difficult. Collect fleshy 

fruits in white plastic bags, and store them in a cool place 

or a refrigerator until they are cleaned.

Figure 2.5—The seeds of some dry fruits, such as hazel nuts, are enclosed in a thin papery shell (A). Penstemon fruits are capsules 

(B) that contain many small black seeds (C).

A

B

C

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16 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

2.3.1.3 Grasses and Forbs—Seeds of native grasses 

and forbs (herbaceous plants) are not contained in dry 

or fleshy fruits, and they can be collected directly from 

the plants. Grass seed heads form at the top of the plants 

(Figure 2.7A) and the seeds are contained in a papery 

sheath (Figure 2.7B). Forb seed heads form directly 

Figure 2.6—Fleshy fruits, such as mountain-ash 

berries, contain small tan seeds (A). Chokecherries 

grow in a raceme (B), and each berry contains a 

large hard seed (C).

A

B

C

Figure 2.7—Native grasses produce seedheads that are a 

papery sheath (A) containing many seeds (B). Forb seedheads 

develop directly from flowers (C), and seeds (D) are contained 

within papery or woody structures.

from the flowers (Figure 2.7C); seed heads are therefore 

variable in size and shape and the seeds can be handcollected (Figure 2.7D). Photos and illustrations can be 

found on the USDA Natural Resources Conservation 

Service PLANTS database (http://www.plants.usda.gov). 

A

B

D

C

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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 17

Other non-dormant seeds, such as willow or azaleas, are 

sown without further preparation or cleaning. With these 

species, the cottony material that surrounds the tiny seeds 

can aid in holding seeds in contact with the soil when they 

are planted. 

2.5.2 Cleaning Dry Fruits, Capsules, and Seed 

Heads 

The first step in cleaning seeds is to remove them from 

the cones, capsules, or seed heads. You can extract small 

quantities of seeds and clean them reasonably well at home 

with simple, low-cost equipment. As cones and capsules 

dry, they open and seeds fall out. Properly dried fruits 

will partially open inside the sacks and some seeds will 

fall out. To remove all the seeds, however, they may need 

further drying. They will dry best if placed in window 

screen-bottomed trays (Figure 2.8), which are placed in 

warm locations with good air circulation. Adding wooden 

spacers at each corner allows the boxes to be stacked, and 

fans will accelerate drying. If you have small batches of 

fruits, place them in a paper sack instead, but leave the top 

open. When most seeds fall out with a little gentle tapping, 

the cones or fruits have opened sufficiently. When true fir 

cones dry sufficiently, they disintegrate into scales and 

seeds.

2.4 Handling Seeds and Fruits 

After Collection

After harvest, begin drying cones, fruits, and seed 

heads as soon as possible. Freshly collected fruits, 

whether they are dry or fleshy, have high moisture 

content and will mold if stored inappropriately even 

for a few days. Drying reduces the moisture content of 

the seeds, helps open dry fruits, and prepares seeds for 

further cleaning. Good air circulation, low humidity, and 

temperatures maintained at 64 to 80 °F are ideal conditions for post-harvest drying. A ventilated storage shed 

works well for this purpose. Temperature control is very 

important; keep temperatures cool. Poor air circulation 

can also cause severe seed damage. Spread cones, dry 

fruits, and seed heads over a mesh screen with fine holes 

that allows air movement to promote even drying and 

eliminates moisture build up, but prevents seeds from 

falling through the screen. For dry fruits and cones that 

split open at maturity, cover the collection with a fine 

mesh cloth to prevent the loss of seeds after fruits begin 

to split open. Small quantities of dry fruits can be dried 

in paper bags or large envelopes as long as the bags are 

not packed too tightly with collected material. 

2.5 Seed Cleaning and Extraction

Seed cleaning is necessary so that seeds can be sown or 

stored properly. In some cases, seeds will fail to germinate 

if they are not removed from their fruits. The seed cleaning area should be well ventilated because some fruits can 

cause allergic reactions and fine dust can irritate eyes and 

lungs. It is important to wear gloves and dust masks during 

cleaning, and wash your hands afterwards. 

Seeds can be cleaned from fruits in many, easy ways. 

Some are described below. It is important to remember 

that dormant seeds need to be spread evenly and dried 

completely before storage, while non-dormant seeds need 

to be kept moist and in a high humidity environment until 

they are sown. 

2.5.1 Cleaning Non-Dormant Seeds

Large seeded, non-dormant seeds are typically cleaned 

from other debris by floating them in water immediately 

after collection. This keeps seeds hydrated and facilitates 

the removal of non-viable seeds, trash, and other debris 

that will float. If nuts and acorns are collected under very 

dry conditions, good seeds may also float. Therefore, soak 

large seeds in water overnight to allow enough time for 

good seeds to hydrate and sink. 

Figure 2.8—Screen-bottomed boxes are an excellent way to 

allow conifer cones, dry fruits, and seedheads to dry without 

losing the seeds.

Chapter 2—Obtaining and Preparing Seeds
18 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

The next step is to separate seeds from cones, fruits, and 

other debris. Separation is typically accomplished with a 

combination of screening and air separation. Move the dry 

fruits and seeds to another screen box with a mesh size large 

enough to permit the seeds to fall through (Figure 2.9A). 

Gentle shaking will let seeds and smaller impurities fall 

through the screen, leaving cones and larger debris on the 

screen. Screen mesh size will vary greatly with species. For 

example, a 1⁄4 - to 1⁄2-inch mesh works well for Douglas-fir, 

while a 3⁄8- to 5⁄8-inch mesh is necessary for larger true 

fir seeds. But with other small seeded plants like sedges, 

rushes, and some wildflowers, you will need very fine 

mesh screens or kitchen sieves to properly separate seeds 

from other debris. Extracted seeds may be mixed with pitch 

globules, dry leaves, wings, and other debris. Repeat the 

screening process with a mesh size that retains seeds but 

allows the smallest debris to pass through (Figure 2.9B). 

You’re then left with seeds and seed-sized debris.

Many native plant seeds have wings or other appendages 

that need to be removed to make sowing easier. Wings can 

be manually removed by filling a burlap or cloth sack 1⁄4

full, tying or folding it shut, and gently kneading the seeds 

by squeezing and rubbing the sack between your hands 

(Figure 2.10). Friction between seeds and between seeds 

and burlap will detach wings. Remember to knead slowly 

and gently because too much friction might damage seeds. 

Another trick for dewinging conifer seeds is to alternately 

moisten the seeds and let them dry, and then repeat the 

rubbing process. A few species, such as alder, western 

redcedar, and angelica, have very tight wings that should 

be left on the seeds. Repeat the screening process again 

with a mesh size that retains seeds but allows the smallest 

debris to pass through.

The final step in the seed cleaning process is fanning or 

winnowing, which separates detached wings, hollow seeds, 

and seed-sized impurities from good seeds. Winnowing 

can be done outside on a breezy day or, for smaller batches, 

just cup the seeds in your hands and blow through them 

while gently bouncing the mixture. For larger batches, 

winnow in front of an electric fan, which separates seeds 

Figure 2.9—Wooden frame boxes with screened bottoms (A) can be used to separate seeds from other debris. Depending on 

the type of dry fruits and seed size, several boxes with different sized mesh may be needed. With gentle shaking over a series of 

screens, pure seeds can eventually be obtained (B).

A B

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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 19

from the lighter debris (Figure 2.11). Most heavy, sound 

seeds will come to rest near the base of the fan, and hollow seeds, wings, and lighter impurities will tend to blow 

farther away. Changing the fan speed or moving farther 

way will improve the separation. After each winnowing, 

collect a small sample of seeds and cut them in half to 

Figure 2.10—Many native plant seeds have wings or other 

appendages that must be removed before sowing. An easy 

way to de-wing seeds is to put them in a cloth bag and gently 

knead the bag and seeds.

Figure 2.11—Winnowing in front of a fan separates filled seeds from empty seeds and other 

lighter debris. 

check for soundness. This way you can determine where 

the hollow seeds are and discard them. All species will 

probably require several successive separations to obtain 

a desired degree of seed purity. A good target for most 

species is 90% or more sound seeds. 

2.5.3 Cleaning Fleshy Fruits 

Fleshy fruits should be processed soon after collection 

to avoid fermentation, mummification, heat buildup, 

or microbial damage. Just before cleaning, soak fleshy 

fruits in water to soften the pulp. Fruits can be soaked 

for a few hours to a few days, depending on the species. 

Change the water every few hours during soaking. 

Flesh can be hand squeezed or mashed using a wooden 

block, rolling pin, or other device. Fruits can be also be 

cleaned by wet screening, which involves hand rubbing 

the fruits against screens using a steady stream of water 

to eliminate the pulp.

A modified food blender or kitchen food processor 

(Figure 2.12A) can be used for small lots of fleshy fruits. 

Just coat the impeller blades with rubberized plastic or 

tape (Figure 2.12B) so that seeds are not damaged during 

cleaning. The final processing step is to thoroughly wash 

seeds with fresh water to remove any remaining pulp, and 

then place them on a drying rack for several days before 

storage. 

Chapter 2—Obtaining and Preparing Seeds
20 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Remember, how seeds and fruits are handled during 

collection, temporary storage, post harvest handling, and 

cleaning can directly affect seed quality, viability, and 

storage life.

2.6 Storing Seeds

Most seeds can be sown immediately after cleaning. Immediately after harvesting and cleaning, sowing seeds into 

bareroot beds or containers left outdoors exposes seeds to 

their normal cycle of climate and allows any dormancy to 

be overcome naturally (see Section 2.7, Seed Dormancy). 

In the case of spring ripening seeds, such as elm, they 

can be planted immediately and will germinate and grow 

during summer. Seeds that are sensitive to drying, such 

as acorns, willow, and Culver’s root, perform best when 

sown immediately. Sowing immediately after harvest is 

the best option when you have as many seeds as you need, 

have adequate outdoor space prepared, and can protect 

the seeds from predation while they undergo exposure to 

natural conditions. Storing seeds will be necessary if you 

have collected more seeds than you need in a single year 

and expect to use those seeds in the future, if you are not 

ready to plant the seeds, or if the conditions simply are not 

favorable for planting immediately. If stored, most seeds 

require some treatment to alleviate dormancy (see Section 

2.8, Seed Treatments; Appendix 6.1). Seeds that require 

scarification (see Section 2.8, Seed Treatments) need to 

be treated before sowing whether they are stored or not.

To properly store seeds, they must be mature and free 

of mechanical injury. The key to good seed storage is to 

control moisture content and temperature. Remember that, 

in general, non-dormant seeds normally remain viable only 

for a few days to 1 year and must be stored moist. Some 

nut and acorn bearing species can be stored for several 

months, as long as seeds have high seed moisture content 

(35 to 50%) and are stored under cool and moist conditions. 

To provide constant gas exchange, non-dormant seeds are 

usually stored in unsealed containers in plastic bags filled 

with moist peat moss in refrigerated storage. 

Dormant seeds, however, can be dried, which increases 

the amount of time they can be stored. Once dormant seeds 

are clean, air-dry them in drying trays for 2 to 4 weeks to 

reduce their moisture content. At room temperatures, seeds 

can be stored for short periods of time in bottles or plastic 

bags in boxes. Make sure that you label the containers with 

species, collection date, and location (Figure 2.13). 

Figure 2.12—Small batches of berries or other fleshy fruits 

can be cleaned with a modified food processor (A). Coating the 

impeller blades with plastic or tape (B) prevents seed damage.

A

B

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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 21

For larger quantities of seeds, refrigerated storage is 

recommended. All native plant seeds can be stored under 

refrigeration (34 to 41 °F) in airtight containers. If possible, 

use a self-defrosting refrigerator that maintains the humidity at 10 to 40%. If the door is rarely opened, the humidity 

in a self defrosting unit will stay at lower humidity levels. 

Many dormant seeds can be stored for long periods at 

temperatures below freezing; some trees seeds will remain 

viable for 10 years or more. Because high seed moisture 

reduces viability, store seeds in airtight containers. 

2.7 Seed Dormancy 

Dormancy is a fascinating physiological adaptation that 

ensures native plant seeds germinate at appropriate times 

for survival and growth. It also is a mechanism by which 

plants increase the time their seeds remain viable. Seed 

dormancy is, therefore, one of the major challenges to 

growing native plants because it can be highly variable, 

not only between different species but among seed sources 

of the same species. In this section, we will discuss seed 

dormancy types and seed treatments that are used to overcome, or “break,” dormancy. Good information on ways 

to overcome seed dormancy for individual native plant 

species can be found in Appendix 6.1, or on the Native 

Plant Network (www.nativeplantnetwork.org).

2.7.1 Non-Dormant Seeds

Non-dormant seeds germinate immediately after maturation and dispersal from the mother plant. The time it takes 

for the seeds to germinate, however, is variable. Some species may germinate immediately (willow and aster) while 

others may take up to a month to germinate after sowing 

(white oaks).

2.7.2 Dormant Seeds

Dormant seeds are those that do not germinate immediately after maturation and dispersal from the mother plant 

even when the right environmental conditions exist. Causes 

of dormancy are either inside the seed (internal) or outside 

the seed (external) and some species have a combination of 

these. When seeds have more than one type of dormancy, 

that is, internal and external, or more than one type of 

internal dormancy (described below), they are said to have 

“double dormancy.” 

2.7.2.1 Internal Dormancy—Internal dormancy is 

caused by some property of the seed that prevents germination. With some species, certain environmental conditions 

(usually cold and moist) are necessary to change the seeds’ 

metabolic processes and allow germination. With other 

species, the embryo within the seed is under-developed at 

time of seed dispersal and a period of after-ripening (set of 

correct environmental conditions, usually warm and moist) 

is needed for the embryo to fully mature before germination can occur. Some species may require a combination 

of warm, moist conditions followed by cold, moist conditions for an extended period of time before germination 

is possible. 

2.7.2.2 External Dormancy—External dormancy generally describes seeds with hard seed coats that are a barrier 

to water. Depending on species, various environmental 

factors cause these seeds to become permeable during a 

certain time of year, or after several months or years. In 

nurseries, these seed coats must be modified by a technique 

called scarification (see Section 2.8.2, Scarification). Some 

species may have double dormancy so the seeds must first 

be scarified to allow water uptake, and then given additional warm and moist and/or cold and moist conditions 

to alleviate any internal dormancy. 

2.8 Seed Treatments

Soaking some seeds in running tap water for a few hours 

up to several days is often helpful because seeds must have 

exposure to water and oxygen before they can go through 

metabolic changes needed for germination. Stored seeds 

are usually at low moisture content and must become fully 

hydrated before they are capable of germination or before 

temperature can be effective in breaking seed dormancy. 

Soaking seeds in running water also helps to remove any 

naturally occurring chemicals present on or within the 

seeds that prevent germination. 

Seed cleansing is used to remove bacteria and fungi from 

seed coats, and it is particularly important for seeds that 

easily mold or take a long time to germinate. Seed cleansing 

is a standard procedure used at most nurseries to prevent 

Figure 2.13—Controlling moisture content is the most critical 

aspect of seed storage, so place seeds in airtight bottles or in 

zip-lock-type plastic bags in a protective box. Make sure all 

storage containers are properly labeled.

Chapter 2—Obtaining and Preparing Seeds
22 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

one of the most common nursery problems: damping-off 

disease. Running water soaks (Figure 2.14A) can effectively 

cleanse seeds and all native plant seeds will tolerate this 

procedure. Seeds can also be cleansed with solutions of 

household bleach (Figure 2.14B) or hydrogen peroxide 

(Figure 2.14C). For example, two standard procedures are 

to either soak seeds in 3% hydrogen peroxide for up to 4 

hours, or in a 40% bleach solution (2 parts bleach [5.25% 

sodium hypochlorite] in 3 parts water) for 10 minutes. After 

soaking in either bleach or hydrogen peroxide, be sure to 

thoroughly rinse seeds with running tap water. Always 

test treatments on a small sample first to ensure it does 

not damage the seeds.

2.8.1 Stratification 

Many dormant seeds require a cold, moist period before 

they germinate; this happens naturally during winter. Stratification is a nursery term that describes the combined use 

of moisture and temperature to overcome seed dormancy. 

Historically, stratification meant layering seeds between 

moist substrates and exposing them to cold temperatures. 

Although nowadays stratification is often used to describe 

any temperature treatment that causes metabolic changes, 

we will use the historic definition.

During stratification, seeds are kept moist at temperatures 

of 34 to 41 °F. Some species may only require a few days 

or weeks of stratification while other species may require 

several months. Different seed sources of a given species 

may break dormancy at different times during stratification. 

You can expect to see some variation when dealing with 

many seed sources. As a general rule, it is best to use the 

maximum recommended dormancy breaking treatment 

(see Appendix 6.1). Another valuable advantage to stratifying seeds is that it increases germination energy (how fast 

the seeds germinate when placed in favorable conditions) 

and uniformity, which is desirable. If seeds begin to mold 

during stratification, remove them from stratification and 

rinse them thoroughly in running tap water to remove the 

mold. Place the seeds in a clean plastic bag and return to 

the refrigerator. You may need to repeat this process often, 

so keep a watchful eye on your seeds.

A few species have double, internal dormancy that is 

best removed through a combination of a warm, moist 

treatment followed by stratification (see Appendix 6.1). 

The warm, moist treatment enhances the after-ripening 

of seeds with under-developed embryos. Juniper, Pacific 

yew, hawthorns, and trilliums are examples of species that 

often benefit from both treatments. The requirements and 

procedures for warm, moist treatment are basically the same 

as for stratification, except temperatures are increased to 

around room temperature. Again, seeds should be soaked 

in running water for 12 to 48 hours and then placed either 

A B C

Figure 2.14—One of the major reasons for poor germination of native plant seeds is seed coat contamination, so a 

running-water rinse (A) is recommended for all species. Large seeds can be surface sterilized with bleach (B) or hydrogen 

peroxide (C).

Chapter 2—Obtaining and Preparing Seeds
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 23

into a plastic bag or between moistened paper towels. Place 

the bag in a dark area. For some pine species, a 2 to 4 week 

period is probably sufficient, but juniper and yew seeds 

may require 15 to 20 weeks of warmth. (Because of the 

long warm treatment, bareroot growers should probably 

sow juniper and yew seeds in late summer or early fall 

[see Section 3.2.3.2, Sowing and Germination].) Once the 

warm period is over, seeds are transferred to a refrigerator to complete their stratification. Check often for mold 

because it can grow rapidly at the warmer temperatures. 

After stratification, re-soak seeds in running water for 

12 to 24 hours. Soaking ensures the seeds have plenty of 

water to begin the germination process.

2.8.1.1 Naked Stratification—This method is best for 

larger quantities of seeds (more than a handful or two). 

Start by putting seeds into a bag made from bridal mesh, 

cheesecloth, or women’s nylons. A square piece of mesh, 

with seeds placed in the center, can be tied to form a crude 

bag (Figure 2.15A). Don’t put more than a half pound of 

seeds per bag. Label it. Place the bag into a bucket and 

allow water to run through it for 12 to 48 hours. After 

soaking, allow the bag to drip dry for a minute or so and 

suspend it within a plastic bag (Figure 2.15B). Hang the 

bag in your refrigerator for the required time (Table 2.2; 

Appendix 6.1). Check it often for mold. If mold is present, 

gently rinse the seeds in running water and rehang in the 

refrigerator.

2.8.1.2 Sandwich Stratification—This is the best 

technique for small amounts of seeds, for very small seeds, 

and for those species that only require a few weeks of stratification. Loosely stack paper towels about 1⁄8-inch thick 

and moisten them completely. Drain off the excess water 

by vertically holding one end of the towel (Figure 2.16A). 

Then, place seeds one layer deep on half the paper towel 

surface. Be sure to distribute the seeds evenly across the 

moist paper towel so that they do not contact each other. 

This will help prevent the spread of mold to other seeds. 

Fold the paper towels over the seeds (Figure 2.16B). Put 

your sandwich into a clear, plastic zip-lock type bag and 

refrigerate for the required time (Table 2.2; Appendix 6.1). 

Check occasionally to ensure seeds are moist and not moldy. 

If they’re moldy, remove the sandwich. Rinse seeds under 

cool, running tap water. Wash out the zip-lock type bag 

with warm water and soap. Spread seeds onto a new stack 

of moistened paper towels, put the sandwich back into the 

bag, and refrigerate. Keep checking for mold.

Figure 2.15—Use bridal mesh or cheesecloth to make a bag to 

soak and stratify seeds (A). After soaking and draining, place 

the mesh bag into a larger plastic bag and add a little water to 

maintain 100% humidity around the seeds without immersing 

them (B). Don’t forget to label bags properly. 

Table 2.2—Stratification durations for six common native plants. 

See Appendix 6.1 for more species.

Common Scientific Days of

name name stratification

New England aster Aster novae-angliae 60

Beaked sedge Carex utriculata 30 to 60

Dogwood Cornus florida 90

Indian blanketflower Gaillardia aristata 0 to 60

Colorado (blue) spruce Picea pungens 0 to 28

Antelope bitterbrush Purshia tridentata 60 to 90

A

B

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24 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

2.8.2 Scarification

Scarification is any method used to treat hard and impermeable seed coats so that moisture can enter the seeds, 

thus allowing them to germinate. In nature, hard seed coats 

often have a “plug” that must be softened or opened by 

exposure to extreme temperatures or the digestive acids 

in the stomachs of animals. Some species with hard seed 

coats that benefit from scarification include lupine, globemallow, and sumac (see Appendix 6.1). Other species that 

are adapted to fire or inhabit desert environments may also 

benefit from scarification.

Seeds can be scarified several ways, but we will discuss 

only three of the easiest methods. How well the scarification method works depends on the species and the thickness of the seed coats. Whichever method you choose, it 

is very important not to damage the interiors of the seeds. 

Take the time to learn the anatomy of the seeds that you 

are working with. Trying different methods and tracking 

your results will help you determine the best method for 

that species and your seed sources.

2.8.2.1 Mechanical Scarification—The seed coats of 

large seeds can be filed or nicked using a knife or metal file 

(Figure 2.17A). Be sure to scarify on the side of the seed 

away from the embryo. This method is time consuming, 

requires precision so that the seed coat is scarified without 

damaging the seed, and can be dangerous if the knife is 

improperly held. 

Rubbing small seeds with sandpaper can be effective 

for some species, particularly the grasses and sedges, but 

it is difficult to treat all seeds uniformly. One easy and effective technique is to construct a wooden box (4 inches 

wide, 6 inches long, and 1 inch deep), line it with 100 grit 

sandpaper, and then wrap a small block of wood with the 

same sandpaper. Place the seeds inside the box and rub 

them with the wood until the desired amount of abrasion 

is achieved.

Hobby size rock tumblers can be used to scarify hard-coated 

seeds and avoid the potential damage that can occur with 

other scarification methods. You can use a rock tumbler two 

ways: dry tumbling and wet tumbling. Dry tumbling involves 

placing seeds, coarse carborundum grit (sold by rock tumbler 

dealers) and pea gravel in the tumbler. The duration of treatment is usually for several hours, but it is an effective and 

safe way of scarifying seeds of many hard-seeded species. 

After tumbling, the grit can be separated from the seeds using a fine mesh screen, and the grit can be reused. In the wet 

tumbling treatment, water is occasionally added to the grit 

and pea gravel. An additional benefit of wet tumbling is that 

seeds are moistened and chemical inhibitors are leached out. 

Wet tumbling has been effective treatment for species such 

as redstem dogwood and golden currant.

2.8.2.2 Hot Water Scarification—Scarifying seeds 

with hot water works well for many species with hard 

seed coats because it provides a rapid, uniform treatment 

and results can easily be seen within a few hours (Figure 

2.17B). Thickness of the seed coat may vary somewhat 

between sources, so it is a good idea to dissect a few seeds 

and examine the thickness of seed coats from each seedlot. 

A B

Figure 2.16—Sandwich stratification requires paper towels that are moist but not soaking wet, so hold them by the 

corner until excess water drips off (A). Place one layer of seeds on the towels, fold them, place in a plastic zip-locktype bag (B), and refrigerate.

Chapter 2—Obtaining and Preparing Seeds
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 25

Figure 2.18—Germination tests will give you an idea of your 

seed quality (A), and help determine how many seeds to sow. 

When checking your germination test, only count seeds that 

have primary roots as long as the seed coat. Don’t count seeds 

that have leaves emerging instead of roots, or are moldy (B).

Figure 2.17—Large seeds with hard seedcoats can be 

mechanically scarified with a sharp knife or triangular file (A). 

Hot water scarification softens the hard seedcoat and greatly 

speeds germination (B) (courtesy of Greg Morgenson).

B

A

Doing several hot water scarification tests with a small 

number of seeds will help determine the length of time 

needed for treatment.

Seeds are added to boiling water for a few seconds and 

then immediately transferred to a vat of cold water so that 

they cool quickly to prevent embryo damage. If the seeds 

have been scarified they will enlarge while they are soaking 

in the cool water for a day or so. If the seeds have not been 

properly scarified, they will be the same size of the dry, 

non-treated seeds. In this case, you will need to re-treat 

the seedlot. Some species cannot tolerate excessively high 

temperatures, so you may only want to heat the water to 

158 °F or so and monitor your results.

2.9 Premature Germination 

Oh no! You’re not ready to sow but you just checked 

your seeds and a few are beginning to sprout. You will 

need to plant the seeds that have sprouted (see Chapter 4), 

but you can slow down the germination process with the 

remaining seeds. Remove the non-sprouted seeds from 

stratification and gently spread them out to surface dry. 

Allow the surface of the seed coat to dry until it’s dull, not 

glossy. Put the seeds back into a plastic bag and refrigerate. The reduced moisture content will greatly reduce the 

germination process. 

2.10 Germination Testing

A germination test will tell you how well your filled 

seeds will sprout (Figure 2.18A). If you have just a few 

seeds and plan on growing only a few seedlings for fun, 

a germination test is unnecessary. A germination test 

will, however, help you use seeds efficiently and grow 

higher-quality seedlings. For species that require these 

treatments, germination tests usually start by scarifying 

and/or stratifying seeds. After stratification, rinse seeds 

in running water for 12 to 24 hours. If you test nonstratified seeds, rinse them at the same time, but for 24 

to 48 hours. Stack paper towels about 1⁄8-inch thick and 

moisten them completely. Drain off the excess water by 

holding towels as shown in Figure 2.16. Put the paper 

towels into your plastic container and spread seeds over 

it, maintaining each group. Close the lid and place the 

container in a location with room temperature and out 

of direct sunlight. Every 5 days thereafter, count seeds 

with primary roots at least as long as the seedcoat, and 

remove them from the test (Figure 2.18B). After 30 days, 

you can record percent germination. Another value you 

may obtain is germination energy. Germination energy 

(also known as germination speed) tells how rapidly 

B

A

Chapter 2—Obtaining and Preparing Seeds
26 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

seeds germinate and is usually given in days. Of the 

total number of seeds to germinate, check to see by what 

day 50% had sprouted. Ideally, most will germinate in 

the first 10 to 21 days or sooner. If not, your seeds may 

need a longer stratification period.

2.11 Additional Reading 

Banerjee, S.M.; Creasey, K.; Gertzen, D.D. 2001. Native woody plant 

seed collection guide. Victoria, British Columbia: British Columbia 

Ministry of Forests. 146 p.

Bonner, F.T.; Karrfalt, R.P., eds. 2008. The wood plant seed manual. 

Agric. Handb. 727. Washington, DC: U.S. Department of Agriculture, 

Forest Service. 1223 p.

Dumroese, R.K.; Luna, T., Landis, T.D., eds. 2008. Nursery manual 

for native plants: a guide for tribal nurseries. Volume 1, Nursery 

management. Agric. Handb. 730. Washington, DC: U.S. Department 

of Agriculture, Forest Service. 302 p.

Kock, H.; Aird, P.; Ambrose, J.; Waldron, G. 2008. Growing trees from 

seed: a practical guide to growing native trees, vines and shrubs. 

Richmond Hill, Ontario: Firefly Books. 280 p.

Luna, T.; Wilkinson, K.M. 2010. Collecting, processing, and storing 

seeds. In: Dumroese, R.K.; Luna, T.; Landis, T.D., eds. Nursery 

manual for native plants: a guide for tribal nurseries. Volume 1, 

Nursery management. Agric. Handb. 730. Washington, DC: U.S. 

Department of Agriculture, Forest Service: 112-131. 

Luna, T.; Wilkinson, K.M.; Dumroese, R.K. 2008. Seed germination 

and sowing options. In: Dumroese, R.K.; Luna, T.; Landis, T.D., 

eds. Nursery manual for native plants: a guide for tribal nurseries. 

Volume 1, Nursery management. Agric. Handb. 730. Washington, 

DC: U.S. Department of Agriculture, Forest Service: 132-151.

Steinfeld, D.; Archibald, C. 1999. Propagating native grass seed and 

seedlings. In: Rose, R.; Haase, D.L., eds. Symposium proceedings—Native plants: propagating and planting; 9-10 Dec 1998; 

Corvallis, OR. Oregon State University, Nursery Technology 

Cooperative: 32-37.

Chapter 2—Obtaining and Preparing Seeds
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 27

Chapter 3. Growing Plants 

From Seeds

You can grow your seedlings two ways: in the ground 

or in containers. Naturally, both have advantages and 

disadvantages. In general, seedlings in the ground (called 

bareroot seedlings) grow slower than seedlings grown in 

containers, especially when containers are in a greenhouse 

or sheltered growing area. For the novice, the choice boils 

down to personal preference, space availability, whether 

or not you have a greenhouse, and soil quality.

3.1 The Importance of Quality Water

Water is the most important biological factor controlling plant growth, so the quantity and especially 

the quality of irrigation water are critical to growing 

native plants. For irrigation purposes, water quality is 

determined by two factors: 1) the concentration and 

composition of dissolved minerals often referred to as 

“soluble salts” or “dissolved salts,” and 2) the presence of 

harmful fungi, weed seeds, algae, and possible pesticide 

contamination. Groundwater and surface water are the 

two sources of irrigation water, although surface water 

from streams, reservoirs, or lakes is more likely to be 

contaminated with fungal pathogens or weed seeds. Dissolved salts are a more serious problem because there is 

no inexpensive way to remove them (Figure 3.1). For our 

purposes, we define a salt as a chemical compound that 

dissolves in water into positively and negatively charged 

particles called ions. Using this definition, fertilizer is 

also a salt. Therefore, salts in the proper concentrations 

can be beneficial, but too much of any salt can also be 

harmful. We recommend you have your water tested by 

a laboratory; water tests are relatively inexpensive and 

can identify problems before you start growing plants, 

which can save money in the long run.

A

B

Figure 3.1—Good quality water is critical for growing native 

plants (A), and the concentration and composition of dissolved 

minerals, often referred to as “soluble salts,” are the major 

concern (B). Young plants can be damaged by moderate salt 

levels, so get your water tested.

Chapter 3—Growing Plants from Seeds
28 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

3.2 Growing Bareroot Seedlings

3.2.1 Nursery Site Selection

One of the most important factors in selecting a nursery 

site is soil texture, which refers to the fineness or coarseness of a soil (Figure 3.2). “Light” or “coarse” soils are 

predominately sandy, with some finer particles of silt and 

clay. Light soils have fast water infiltration, drain well, and 

are easy to work. “Heavy” or “fine” soils are predominately 

comprised of silts and clays, with just a few coarser sand 

particles. Heavy soils have slow water infiltration, drain 

slowly, and get very hard and crack when dry. A good 

Figure 3.2—How to determine soil texture by the feel method. Adapted from Colorado State University 

Extension Publication (GardenNotes #214 at http://www.ext.colostate.edu/mg/gardennotes/214.

html (accessed 23 Jan 2012).

Chapter 3—Growing Plants from Seeds
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 29

nursery soil for bareroot seedling production has at least 

40% sand particles, and no more than 40% silt particles 

or 25% clay particles (see Figures 3.2 and 3.3A for determining your soil texture). The best soil for growing 

seedlings is a deep, crumbly, loamy sand, or sandy loam 

that drains well and maintains a loose structure during 

prolonged wet weather (Figure 3.3B). Bareroot seedlings 

must be harvested during winter when they are dormant 

and soils are wet; removing seedlings from sandy soils 

causes less damage to fine roots than removing them 

from heavier soils. Farmers and gardeners use the term 

“tilth” in describing good soils. Although tilth is hard to 

describe in words, you can feel it when you are working 

with a shovel. You should be able to spade a good nursery 

soil, one with good tilth, and it should break into crumbs, 

not clods, and be at least a foot deep. Avoid soils with a 

claypan, hardpan, numerous rocks or bedrock within 18 

inches of the surface. The soil should have a pH between 

5.0 and 6.0. We’ll discuss below what to do with marginal 

soils on otherwise good sites.

Try to find a gently sloping (1 to 4%) bench, long 

slope, or ridge top where late spring or early fall frosts 

are unlikely. In general, a northwestern aspect is better 

because seedling growth begins later and is less subject to 

frost damage, and the soil surface dries more slowly, but 

at high elevations with sufficient water, a southerly aspect 

is better.

Unfortunately, sandy loam soils are usually associated 

with river bottoms or other flat areas. Freezing air flows 

like water from higher slopes down to flat lands at lower 

elevations, and such areas are known as “frost pockets.” 

Even on sloping ground, a physical obstruction such as the 

edge of a timber stand or topographical barrier may form 

an “air dam” and cause a frost pocket effect. Seedlings 

growing in frost pockets can experience shoot die-back, and 

may frost heave during winter (the lifting action caused by 

repeated freezing and thawing of the surface layer of soil).

Low-lying flat areas may also accumulate standing water 

during prolonged rainy seasons. Waterlogged soil is damaging or fatal to seedlings because of oxygen depletion in 

the soil or buildup of toxic gases. Poorly drained soils are 

conducive to several fungi that weaken or kill seedlings. 

You may be able to correct drainage problems with tile or 

careful leveling, but the best long-term solution is choosing 

a well-drained site.

Good nursery sites require full sun, otherwise most seedlings grow weak and spindly. Avoid root zones of adjacent, 

large trees because they invade seedbeds and deplete soil 

moisture and nutrients. If you must sow near larger trees, 

root competition can be controlled by trenching 3-feet deep 

between the trees and your nursery.

Windbreak trees planted near your nursery should be a 

different species than crop seedlings because older trees 

may harbor insects and diseases harmful to nursery seedlings. For example, cottonwoods and aspens are alternate 

hosts for Douglas-fir needle rusts, and gooseberries (Ribes

species) should not be grown near white pine because they 

are an alternate host of a serious disease.

Figure 3.3—Good nursery soils are “light” in texture and 

sandy loam soils are ideal with high percentages of sand and 

lower percentages of silt and clay (A). Healthy soils contain 

earthworms and other beneficial organisms (B).

B

A

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3.2.2 Site Preparation

How big a nursery site will you need? Well, it depends 

on how many seedlings you plan to grow. Plan on growing 

about 25 seedlings per square foot using beds 4 feet wide 

(so you can reach the centers). Therefore, each lineal foot 

of nursery bed will yield 100 seedlings. For example, if you 

want to grow 1,000 seedlings, the length of bed required 

would be 1,000 divided by 100 = 10 feet. So a 4 x 10 foot 

bed would be sufficient. Plan on adding about 50% more 

space for walkways between beds.

Your soil should be thoroughly worked at least 12 inches 

deep the year before sowing. If your site was recently cultivated and is free of heavy sod and weeds, one plowing in 

fall is sufficient. That plowing should be followed in spring 

by fine disking and harrowing, rototilling, or spading and 

raking just before laying out your beds. Just a note about 

rototilling—do it sparingly and at a low RPM. Rototilling 

enhances the breakdown of soil organic matter and soil 

structure, two characteristics of soil beneficial to seedling 

growth.

If your site hasn’t been recently cultivated, deeply 

plow and grade the soil a full year before establishing 

beds. Heavy debris like roots, rocks, wood chunks, 

and other foreign matter should be removed. This 

should be followed by summer fallowing (repeated 

cultivation) to break down heavy organic matter and 

control new growth of grass and weeds. Persistent, 

deep-rooted plants like blackberries, thistles, bindweed, and quack grasses should be eradicated with 

herbicides during the early summer growing season 

(please consult your university extension agent or 

Natural Resources Conservation Service [NRCS] 

representative for proper chemicals and application 

rates; use them only with a great deal of caution for 

the crop, yourself, and the environment—always read 

and follow label directions).

If you have an otherwise good site but only marginal soil, you’ll have to modify the soil with large 

quantities of amendments. Either incorporate sandy 

loam soil or organic matter. We recommend organic 

material, including peat moss, garden compost, 

ground and composted leaves, and well-composted 

manure. Adding organic amendments and/or coarse 

sand to heavy clay loams will improve drainage, 

texture, tilth, and fertility. Put the amendment about 

6 inches deep on top of the soil (about 2 cubic yards 

of amendment per 100 square feet of soil to be 

treated), and then work it into the soil to a depth 

of 12 inches. Sawdust, a readily available source of 

organic matter, can be used as an amendment with 

caution (see Section 3.2.6, Soil Management).

Test your soil for pH, soil acidity, with kits available at 

garden centers or through gardening catalogs. Soils with 

pH below 7.0 are considered “acid” while those above 7.0 

are considered “basic” (Figure 3.4). A good nursery soil 

for native plants should have a pH between 5.5 and 6.5. 

If your soil pH is too high (more than 6.0), add sulfur to 

bring it down. Conversely, if the soil is too acidic (less than 

5.0), add lime to increase pH. The actual amounts of sulfur 

or lime needed to achieve the desired change in pH vary 

with the amounts of sand, silt, and clay in your soil. You’ll 

need a more complete soil test and some expert advice in 

order to apply the correct amounts. Soils can usually be 

tested at universities or other testing laboratories and test 

results often include sulfur and lime recommendations. 

Ask your university extension agent or NRCS representative for nearby laboratories.

Figure 3.4—The ideal nursery soil has a pH of from 5.5 to 6.5, 

so have your soil tested.

Chapter 3—Growing Plants from Seeds
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 31

3.2.3 How to Grow Seedlings

Generally, it takes 1 to 2 years to grow bareroot, woody, 

native plant seedlings large enough for planting, but some 

slow-growing species like bristlecone pine may take 3 or 

4 years. Most conifer seedlings are grown 2 years in the 

same nursery bed, and professional nursery managers call 

them 2+0 seedlings (2 years in the same bed without any 

years in a transplant bed). Huskier seedlings can be grown 

by transplanting 2+0s into another bed for an additional 

year. These would be called 2+1s. Many eastern deciduous trees and shrubs and conifers of the southeastern U.S. 

can be grown in a single year, whereas conifer seedlings 

at more northerly latitudes and in the western U.S. require 

2 years. For the sake of discussion, let’s assume you’ll be 

growing 2+0 seedlings.

3.2.3.1 Fertilizers: Organic vs. Synthetic—Plants require 13 nutrients to sustain healthy growth (Figure 3.5); 

sometimes these are referred to as minerals or elements. 

Six of these nutrients are called macronutrients because 

the plant requires them in greater amounts than the other 

seven, called micronutrients, which are required only in 

very small amounts. Of the six macronutrients, three are 

considered the primary, or most important, nutrients for 

healthy plant growth and are commonly supplied through 

fertilizers: nitrogen (N), phosphorus (P), and potassium 

(K). Nitrogen is critical for aboveground plant growth, 

especially new shoots, needles, and buds. Plants lacking 

sufficient N grow slowly or are stunted and have pale green 

or yellow needles. In young seedlings, P is important for 

root growth and bud development. Potassium is necessary 

for root growth, efficient water use by the plant, and improved disease resistance. The secondary macronutrients 

and micronutrients are normally present in fertile soil or 

supplied through irrigation water. Soil tests are necessary 

to diagnose nutrient deficiencies.

Nutrients can be supplied to your plants through either 

organic fertilizers (for example: manure, compost, kelp) 

or synthetic fertilizers that are available at garden centers 

or farm chemical suppliers. To a native plant seedling, a 

molecule of nitrate nitrogen is the same whether it comes 

out of a cow or out of a bag purchased at a garden center. 

In general, organic fertilizers have low percentages of 

N:P:K; N ranges from 0.5 to 1.5% in manure and 2 to 4% 

in composts, whereas synthetic fertilizers have much higher 

concentrations of N, ranging up to 33% or more. Because 

organic fertilizers like manure and compost are associated 

with lots of decomposing organic matter and microorganisms (bacteria and fungi), and organic matter is important 

to healthy soil, one benefit of using organic fertilizers is 

the organic matter and microorganism additions. Because 

synthetic fertilizers don’t supply it, organic material should 

be added to nursery soil.

Fertilizer can be applied to seedlings two ways: incorporated into the soil or applied over the crop (top-dressing). 

The application technique depends on the solubility of the 

fertilizer. Nitrogen and K fertilizers are soluble so they can 

be top dressed and your irrigation water will carry them 

down to the roots. However, P is not soluble so it must be 

incorporated into the root zone before sowing the crop.

How much fertilizer should you apply? Too much fertilizer is a common mistake. It’s better to put slightly less 

fertilizer on a crop rather than too much. Remember that 

the label on any fertilizer always shows the percentages 

of N, P, and K, and always in this order: N:P:K. (Well, 

that’s not completely true, and this can be made really 

complicated, which we show in Appendix 6.2.) Here’s the 

easiest approach that should work for most situations. Using 

a whirlybird type spreader or a drop-type spreader, apply 

fertilizer evenly across the bed. Before sowing, incorporate 

2.5 pounds of 0:20:0 (calcium superphosphate) into every 

100 square feet of nursery bed. Use a spade or rototiller 

to work the fertilizer into the ground.

Figure 3.5—Plants need 13 nutrients for healthy growth, 

especially the three primary macronutrients found in most 

fertilizers: nitrogen, phosphorus, and potassium.

Chapter 3—Growing Plants from Seeds
32 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Once seedlings are growing, top dress seedlings (apply 

fertilizer over the tops of seedlings) at a rate of 7 ounces of 

10:10:10 (N:P:K) per 100 square feet of nursery bed three 

times during summer (mid-June, early July, mid-July) and 

again in mid to late September. The mid-June application 

should be avoided if damping-off is a problem. Water immediately after applying the fertilizer to wash it off foliage 

and move it into the ground where it’s available to roots.

If you care to be more intense with your fertilization 

program, the result being larger seedlings in less time, check 

the appendices for necessary formulas for determining the 

amounts of different fertilizers to apply. Some examples 

are provided for fertilizers to use on acidic soils with pH 

under 6.0 (Appendix 6.2.1), basic soils with pH more than 

6.0 (Appendix 6.2.2), or if you want to use a strict organic 

fertilization program (Appendix 6.2.3).

3.2.3.2 Sowing and Germination—After incorporating fertilizer and/or adjusting soil pH, make sure your 

nursery bed is smooth and level. Professionals usually make 

beds that are 4 feet wide and raised 3 to 6 inches, but you 

can make raised beds of any size using redwood or cedar 

boards for siding. Raising the beds promotes drainage 

and soil-warming, which encourages faster germination 

and root growth; saturated soil stays cooler and promotes 

damping-off and root diseases.

You may sow either in rows or by broadcasting. Either 

way, the idea is to get enough seedlings per square foot to 

achieve good seedling growth without causing too much 

competition between seedlings. If you broadcast sow (Figure 3.6A), spread three-fourths of the seeds evenly over 

the nursery bed. Mixing a little baby powder (talc) on the 

seeds, especially when they are small, makes them easier 

to handle and easier to see on the ground. Use remaining 

seeds to fill any “holes.” Gently press seeds into the soil 

with a board and cover with a light layer of mulch. When 

properly done, broadcast sowing results in even-spaced 

seedlings that have room to grow (Figure 3.6B).

Sowing seedlings in rows or “drills” (Figure 3.6C) may 

take more time, especially if you manage the within-row 

distance between seeds, but it’s worth it —you’ll spend less 

time weeding, root pruning, and harvesting, and you’ll grow 

more uniform, nicer-looking, healthier seedlings. Rows are 

typically about 6 inches apart for most species. Probably 

the easiest way to sow in rows is by using a marking board 

(Figure 3.6C). Based on your germination percentage, 

sow enough seeds so you’ll have about 25 seedlings per 

square foot after germination is complete (Table 3.1). If 

you plan to transplant the seedlings after the first growing season, you may use densities up to 50 seedlings per 

square foot. A handy tool, especially for smaller seeds, is 

a vibrating hand seeder, available in garden centers and 

through mail-order nursery catalogs. If you are sowing a 

lot of seeds, you should consider a walk-behind precision 

garden seeder like the Cole Planet Junior (Figure 3.6D), 

which can handle many sizes of seeds.

Regardless of when or how seeds were sown, most species 

should be covered by a thin (1⁄8- to 1⁄4-inch-thick) mulch of 

pine needles, sawdust, fine-screened bark (1⁄8-inch diameter), sand, very fine gravel, or screened garden compost 

(only use the fines). Mulch should be no more than twice 

the thickness of the seed, and will keep seeds from drying out. Sowing seeds too deep is a common and serious 

mistake (Figure 3.7). Seeds that should not be covered 

include those that are very small (for example, sagebrush) 

or require light for germination (for example, birch).

Seeds may also be sown in fall, allowing them to stratify 

under natural conditions. Fall sowing can be particularly 

advantageous for species that required some warm, moist 

treatment before stratification (see Appendix 6.1). Fall-sown 

seeds must be protected from predators, especially mice 

(see below), and from drastic variations in temperature. To 

Damping-off

Germinating seeds and young seedlings are very susceptible to diseases, which are collectively known as 

“damping-off.” Several factors including fungi, chemicals, 

or high-temperatures can cause the stem tissue to collapse 

at the ground surface. When fungi cause damping-off, the 

roots are dark and decayed, discolored roots; however, 

when seedlings damp-off because of chemical damage or 

heat injury, the root remains white. Damping-off is most 

serious on seeds with low germination percentages, seeds 

germinating during periods of cold and wet weather, and 

when seedbeds are watered too much. Damping-off can 

be minimized by using clean seeds and well-drained soil. 

If damping-off is particularly bad, refrain from using any 

nitrogen fertilizer because this worsens the disease. Remove 

and discard dead and dying seedlings immediately to help 

prevent infection of other seedlings.

Chapter 3—Growing Plants from Seeds
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 33

Table 3.1—For the germination percentage of your seedlot, and assuming you’ll sow 

10% extra for losses and that your rows are 6 inches apart, this table provides an estimate of how many seeds to sow per square foot and how far 

apart those seeds should be in each row. 

Seeds to sow

Germination Seeds to sow assuming a 10% loss Inches between

percentage per square foot during the first year seeds in rows

80 to 100 32 to 25 35 to 27 1 to 11⁄4

60 to 80 42 to 32 46 to 35 3⁄4 to 1

40 to 60 62 to 42 68 to 46 1⁄2 to 3⁄4 

20 to 40 125 to 62 138 to 68 1⁄4 to 1⁄2

Figure 3.7—Sowing at the proper 

depth is critical and varies with seed 

size. Seeds that are sown too shallow 

will dry out or be eaten by birds or 

rodents, but seeds sown too deep 

will not have the energy to push to 

the surface.

Figure 3.6—Broadcast sowing can be done by hand (A) or with a whirly bird seeder. The biggest problem 

with broadcast sowing is controlling plant density – these seedlings are much too dense (B). Row or “drill” 

sowing can be done by hand using a marking board (C) or a walk-behind seeder like the Cole Planet 

Junior (D) adapted from Raising Forest Tree Seedlings at Home, Pacific Northwest Cooperative Extension 

Publication PNW 96, 1981. 11 p..

A

B

C

D

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34 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

protect seeds from drying and frost heaving, fall sowings 

will need to be covered with a thick mulch. A 2-inch-thick 

layer of straw works well, but it must be removed in early 

spring to allow germination.

Newly sown seeds should be protected from pests, 

especially mice and birds. Covering seedbeds with mesh, 

elevated 6 to 12 inches above the soil but extending to the 

soil around the edges, will minimize losses to birds. If 

the mesh is small enough, this will also exclude mice and 

help prevent wind and water erosion. Keep the area near 

your seedbeds free of weeds and debris to eliminate hiding 

places for mice and other pests.

Water sparingly during germination and emergence—

“moist, but not wet” is a good rule of thumb. A few light 

mistings on sunny days are better than one thorough watering. Remember, sprouting seeds are very susceptible to 

damping-off, which is a serious problem when seedbeds 

are overwatered.

3.2.3.3 Young Seedlings: Establishing Your Crop—

About a month after germination, check your seedling 

densities. If you have more than 40 seedlings per square 

Figure 3.8—Weeds should be controlled by hand (A) or with herbicides, and it’s much 

easier when they are small. Maintaining a good seedbed mulch has many benefits (B).

foot and don’t want to transplant after the first growing 

season, consider thinning seedlings to 25 to 30 per square 

foot to ensure healthy growth. Discard thinned seedlings 

the same way you discard diseased seedlings—burn or 

bury them.

Remove weeds diligently by pulling or apply herbicides 

before they grow large and interfere with growth of your 

seedlings (Figure 3.8A). Use herbicides with a great deal 

of caution for the crop, yourself, and the environment—

always read the label. Make sure you control weeds in and 

around your nursery beds, too. Good weed control efforts 

on the rest of your property will diminish the number of 

weed seeds sprouting in your nursery.

As seedlings grow, maintain a good mulch layer (1⁄4- to 

1⁄2-inch thick). Mulch reduces watering needs, keeps soil 

cool, prevents soil from splashing onto your seedlings, and 

helps retard weed growth (Figures 3.8B). Young seedlings 

can be damaged by high soil surface temperatures so, on 

very warm days, you may need to water to cool the seedbeds. As the stems of your plants grow thicker, they can 

tolerate higher temperature so this type of watering won’t 

be needed.

B

A

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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 35

Some native plants will grow much better if inoculated 

with beneficial microorganisms, such as mycorrhizal fungi 

(Figure 3.9A) or Rhizobium bacteria (Figure 3.9B). You 

can inoculate with soil or duff that you collect from 

beneath the same plant species in the field, or buy commercial inoculum. Many beneficial microorganisms are 

specific to one type of plant so do some research online 

before purchasing any product.

3.2.3.4 Watering—Once seeds germinate, the basic 

philosophy for watering seedlings is to water deeply but 

infrequently (Figure 3.10A). Be sure to wet the entire root 

zone during each watering. How long you need to water 

will depend on how much water is going through your irrigation system, your soil, outside temperature and wind, 

and whether or not you are using a mulch. Keep your 

nursery soil evenly moist—use a small hand trowel to see 

if the soil is dry or moist. Irrigate early in the day to allow 

seedling foliage to dry.

You have a variety of options for watering seedlings, 

from low-tech to high-tech. The easiest technique is using 

a watering can or a garden hose with a soft-spray nozzle. 

This option is fine if you have a small area. Larger areas 

will probably require a less labor-intensive watering system. 

An oscillating yard sprinkler hooked up to a garden hose 

works well, provided you check its output over the entire 

nursery bed, making sure all portions receive adequate 

amounts of water. For larger nursery areas, the next level 

of sophistication would be a fixed irrigation line with systematically spaced nozzles. Such a system will provide a 

more even irrigation, resulting in more uniform seedlings 

and probably less wasted water. Fixed-line systems can be 

placed in exact locations and put on timers to use water 

most efficiently.

Check the output from any sprinkler system by systematically placing small jars, plastic cups, or cans 

throughout your bed (Figure 3.10B). Run the sprinkler 

system for a known time, and then measure how much 

water is in each collection vessel. Once you know how 

long the sprinkler must run to achieve adequate watering, you can put the system on a timer. Some variability 

across the nursery bed is inevitable, but make sure the 

minimum amount of water delivered entirely wets the 

root zone. Unfortunately, sprinklers “waste” a lot of 

water due to evaporation from plants and runoff so water 

early in the morning before it gets too hot and windy.

Drip irrigation lines can be laid along rows of seedlings 

in small seedbeds (Figure 3.10C), or individual emitters or 

drip rings around large transplants. Drip systems are very 

efficient as little water is lost to evaporation (especially if 

covered with mulch), but you’ll have to water for a longer 

period of time due to the slower water application rates.

3.2.3.5 Root Pruning—Root pruning promotes a 

fibrous root system and makes harvesting seedlings 

easier on you and the seedlings. Remember, you can only 

root prune efficiently if you sowed in rows—it’s nearly impossible to root prune broadcast sown seedlings. If you’re 

growing 2+0 seedlings, they need to be undercut at a depth 

of 5 to 6 inches during fall of the first growing season. The 

easiest way to do this is to use a sharp tile spade or shovel 

Figure 3.9—Beneficial microorganisms such as 

mycorrhizal fungi (A) and Rhizobium bacteria (B) can 

improve the growth of some native plants.

A

Chapter 3—Growing Plants from Seeds

B
36 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

A

B C

Figure 3.10—Water is the most important chemical for growing native plants. Deep, infrequent irrigations promotes a strong, 

well-developed root system (A). Check your soil to determine when irrigation is necessary and, if using a sprinkler system, check 

water distribution with a grid of small cans or jars (B). Drip irrigation lines are an efficient way to irrigate bareroot seedbeds (C).

and slice in on an angle under the rows of seedlings (Figure 3.11A). You may have to make angle cuts from both 

directions to ensure seedlings are fully undercut. During 

the second growing season, you’ll want to prune the lateral 

roots 2 or 3 times, first in late spring and the last time in 

late summer (Figure 3.11B). This cutting procedure keeps 

roots of seedlings in one row from intertwining with roots 

of seedlings in another row—a real nightmare to untangle 

when you dig seedlings for planting. Use your sharp tile 

spade or shovel and slice vertically halfway between rows, 

and an equal distance outside the outer row. Schedule root 

pruning so seedlings are watered and fertilized after the 

treatment. Transplants should be root-pruned with the 

same timing and frequency of 2+0s.

3.2.4 Lifting, Handling, and Storage

Nursery managers call the process of digging seedlings 

out of nursery beds “lifting” or “harvesting.” Harvesting 

should be done when seedlings are dormant, either late 

fall, winter, or very early spring before new growth starts. 

Dormant seedlings handle stresses of lifting, storage, and 

planting better than non-dormant stock—the result being 

Chapter 3—Growing Plants from Seeds
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 37

better outplanting survival and growth. Using a garden fork, 

seedlings should be gently dug from the ground, the soil 

gently removed from their roots while preserving the fine 

roots (Figure 3.12A), and seedlings gently put into boxes, 

plastic tubs, or buckets (Figure 3.12B). Gentle handling is 

the key. Always keep the root system moist by wrapping 

roots in wet burlap or covering them with moistened wood 

shavings or chips. Keep harvested seedlings out of the sun 

and wind. If you harvest in the fall for spring planting, wrap 

seedling roots to keep them moist, enclose seedlings in 

plastic bags to prevent desiccation, and keep them cool (32 

to 36 °F). Check often for mold. Storage molds usually begin 

developing on dead foliage. Therefore, be diligent when you 

put seedlings into storage and remove as much dead foliage 

as possible. Storing seedlings in an upright position also 

seems to help reduce mold problems. Remove 

moldy seedlings as soon as they are evident.

3.2.5 Transplanting

 Typically, plant density in a transplant bed is 

much less than in a seedbed, about 10 seedlings 

per square foot (spaced 6 inches by 6 inches apart). 

Because they are planted at wider spacing (Figure 3.13A), transplants grow faster and develop 

better stem diameter (Figure 3.13B) and roots. 

When transplanting seedlings, be sure to place the 

roots in a vertical plane without any twisting or 

kinking (Figure 3.13C). The roots of improperly 

transplanted seedlings become deformed, which 

seriously decreases plant quality. Although plants 

can be transplanted almost any time except when 

they are actively growing, transplanting during 

the fall or early spring is recommended. This 

reduces transplant shock because plants are more 

hardy and weather conditions more favorable. 

Transplants are cultured much the same way as 

seedlings but increased growth rates will require 

more irrigation and fertilizer.

3.2.6 Soil Management

 Between crops, add amendments to maintain 

healthy soil and good tilth. Additions of organic 

matter improve tilth, reduce puddling, increase 

water infiltration, insulate soil, improve soil 

structure, promote better root growth, improve 

soil aeration, make working the soil easier, and 

help suppress root diseases. Adding organic 

matter is necessary because soil microorganisms 

are constantly decomposing it as a food source. 

Good green cover crops include canola, kale, ryegrass, 

and buckwheat. Avoid clovers or be prepared to do a lot of 

weeding of these overzealous seed producers. Clovers also 

tend to promote root disease. Cover crops should be cut and 

worked in while green. Other good organic amendments 

include compost (Figure 3.14), manure, straw, fine-screened 

bark, shredded leaves, and peat. Use 1 to 1.5 cubic yards 

of amendment per 100 square feet of nursery bed (a layer 

about 3 to 4 inches deep), and work it in to a depth of 6 

to 8 inches. With amendments like fresh sawdust, straw, 

leaves, bark, and fresh manure, you should add extra N at 

a rate of 5 to 10 pounds per ton of amendment. Otherwise, 

soil microorganisms that decompose the amendments will 

use all available nitrogen in the soil, leaving little available 

for your seedlings. Soil amendments and cover cropping 

are just good farming practices, and a wealth of good 

information can be found online.

A

B

Figure 3.11—Root pruning with a sharp spade or tile shovel 

during the first growing season helps develop a more fibrous 

root system (A). Vertical pruning of larger plants (B) creates 

moisture stress, which slows height growth.

Chapter 3—Growing Plants from Seeds
38 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Figure 3.12—Harvesting, or “lifting” nursery stock, must be done carefully to minimize injury to fine roots (A). After removing 

them from the seedbed, wrap roots in wet burlap and place bundles of plants in a bucket out of the sun and protected from 

wind (B).

A B

Figure 3.13—Transplanting seedlings increases their growing space (A), which produces plants with larger stem 

diameter and more fibrous roots (B). When transplanting, it is critically important to orient the roots vertically (C) to 

prevent deformation.

A

C

B

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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 39

3.3 Growing Container Seedlings

Seedlings can be grown in containers in a variety of 

propagation environments where growth limiting factors, 

such as temperature, water, and fertilizer, are controlled. 

One big advantage of container plants is that you can grow 

them larger in less time than bareroot stock. However, because container plants have much less moisture reserves, 

you can kill them a lot faster too!

3.3.1 The Propagation Environment

The basic concept is to create an environment where 

as many of the environmental factors that control plant 

growth can be modified (see Section 1.1, Factors That 

Limit Growth). Professional growers constantly adjust 

temperature, moisture, fertilizer, humidity, and sometimes 

even sunlight to keep their crops growing in particular ways 

to produce seedlings of the highest quality. Environmental 

conditions and cultural procedures in your set-up will 

probably be less sophisticated than commercial nurseries, 

and that’s okay. Growing native plants is always a balance 

between ideal conditions and what you can actually afford.

The simplest propagation environment is an open compound where container seedlings are grown outside in an 

area with plenty of sunlight but protected from the wind 

(Figure 3.15A). It’s possible to grow a few seedlings in a 

sunny window or under grow lights (Figure 3.15B), but, 

as we’ll discuss later, native plants need to acclimatized 

to the outside environment. Plastic-covered cold-frames 

(Figure 3.15C), hobby-sized greenhouses (Figure 3.15D), 

and similar structures work well. A good structure will 

allow air circulation on sunny days, block precipitation, 

and provide good light transmission. One problem with 

greenhouses is that they heat-up rapidly so adequate cooling requires an investment into controllers and constant 

monitoring.

Figure 3.14—Organic matter, like this mushroom compost, is 

the ideal amendment to improve the productivity of nursery 

soils.

B

A

C

D

Figure 3.15—Propagation environments can vary from open 

compound (A) to grow lights (B), to cold frames (C), or hobby 

greenhouses (D).

Chapter 3—Growing Plants from Seeds
40 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

3.3.1.1 Growing Media—Garden soils are generally 

too heavy and lack sufficient pore space to grow a good 

container seedling, which is why professional nursery 

managers use soilless potting mixes (“growing media”). 

Many popular growing media use Sphagnum peat moss 

as the major component because of its high water-holding 

capacity and ability to hold nutrients. Because peat moss 

holds a lot of water, however, it is often mixed with other 

components, such as perlite, pumice, or vermiculite 

to increase aeration within the container. Be careful of 

off-the-shelf mixes often sold in garden centers or chain 

stores; sometimes these mixes are just floor sweepings 

after companies package their “professional” grade mixes 

and contain too many “fine” particles that reduce aeration 

and hamper seedling growth.

3.3.1.2 Containers—Professional growers use a variety 

of specialized containers. Common, suitable containers have 

drainage holes in the bottom and vertical ribs on the sides 

to prevent root spiraling (Figure 3.16), which is a serious 

problem with most woody plants. Current nursery jargon 

for containers can be somewhat confusing. For the scope of 

this booklet, an individual container in which the seedling 

grows will be called a “container” and the aggregation of 

“containers” (what holds the containers together) will be 

called a “block.”

Hard-sided plastic containers come in a variety of sizes 

and shapes, and any of them will work well, provided they 

have adequate drainage holes at the bottom, and ribs or 

angular construction (not round in cross section) to keep 

roots from spiraling. This requirement rules out using nearly 

all containers used to grow annual flowers or vegetables 

and found at most garden centers, including pre-formed 

peat pots. Some of the newer containers have slits cut 

in the sides or copper coatings to prevent root spiraling. 

When seedling roots touch the copper, the growing tip is 

stunted, causing the root to branch. The result is a more 

fibrous root system and better root growth all along the 

sides of the root plug.

Two good container types for beginners are flexible 

plastic cells held in hard plastic racks such as the Ray 

Leach Cone-tainerTM (Figure 3.17A) or the DeepotTM (Figure3.17B). Both containers come in several sizes. The main 

advantage of these single cell containers is that cells can 

be moved around and consolidated—empty containers can 

be removed and replaced with containers with seedlings, 

which saves space. This feature can be especially important when growing species with poor or slow germination, 

like many native woody plants. Blank containers provide 

breeding places for nuisance insects like fungus gnats, that 

when present in sufficient quantities, can damage seedlings. 

Also, seedlings will generally grow more uniformly if 

empty containers are removed. If you only plan to grow a 

few crops, these containers are a good choice.

Another good option for beginning growers is peat 

pellets, such as Jiffy pellets. Peat pellets are shipped and 

stored as hard, flat disks of peat moss covered by plastic 

mesh. When watered, the discs expand vertically (Figure 

3.17C). These also come in a variety of sizes and have 

blocks to hold individual pellets (Figure 3.17D). Don’t 

confuse them with peat pots, which are smooth-sided and 

will allow roots to circle. Like single cell containers, peat 

pellets can be consolidated. One advantage is that when 

you get ready to plant your seedlings, you plant the whole 

peat-pellet as well, without the bother of empty containers 

to clean before the next crop. Also, roots will grow out the 

sides of peat pellets, so when outplanted, the root system 

often takes on a more natural looking shape than seedlings 

grown in hard-sided containers that lack a copper coating. 

Another advantage is that the containers need not be cleaned 

between crops, and they are very economical if you plan 

on growing only a few crops. The downside of this feature, 

however, is that you may have to prune the roots between 

peat pellets every month or so to keep the seedling roots 

from intertwining, although the newer style blocks that 

hold the pellets are designed to reduce this problem, and 

they can dry out rapidly in arid conditions.

Figure 3.16—Good containers for growing native plants have 

ribs or slits in the sides to keep roots from spiraling, and drain 

holes in the bottom.

Chapter 3—Growing Plants from Seeds
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 41

3.3.1.2.1 Filling Containers—When filling, it’s important to put a uniform amount of growing medium in each 

container and tamp it down firmly—don’t compact it. If 

containers are filled with varying amounts or density of 

growing medium, seedlings will also vary in size. Overcompacted growing medium restricts root growth, reduces 

shoot growth, and disrupts water drainage, all of which 

increase the susceptibility of your seedlings to root 

diseases.

Spread growing medium evenly over the tops of containers, and gently tap the block a time or two on the table or 

ground to allow settling. Gently dropping it from a height 

of 6 inches onto a concrete floor works well. Then, topdress growing medium over the containers and tap the 

block once again. Next, take a hand brush and sweep extra 

medium out of the containers until the surface is about 

1⁄4 inch below the top of the container (deeper for larger 

seeds). This space will be needed to sow your seeds and 

add some mulch.

If you are going to sow seeds in the same spot as you plan 

to grow the seedlings, go ahead and water your medium 

until water is dripping out the bottoms of the containers. If 

you need to carry containers from where you plan to sow 

them to where you plan to grow them, it will be easier to 

water after sowing.

3.3.2 Sowing and Germination

Depending on your local climate, your propagation environment, and the temperatures you can maintain around 

your seedlings, plan on sowing in early spring. If you can’t 

control temperatures well, you may wish to hold off sowing until late spring to avoid problems with frost. Good air 

A C

B D

Figure 3.17—It’s best to use specialized containers for growing native plants such as the Ray Leach Cone-tainerTM (A), the 

DeepotTM (B), or JiffyTM pellets that expand when irrigated (C & D).

Chapter 3—Growing Plants from Seeds
42 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

temperatures during the germination period range from 65 

to 80 °F. If you have access to bottom heat, use it! Warm 

growing media will help promote faster germination and 

decrease the possibility of disease.

Prepare seeds as described in Section 2.8 (Seed Treatments). Three different techniques are used for sowing 

native plants based on seed size, shape, and ease of germination (Table 3.4).

3.3.2.1 Direct Sowing (20% of Species)—This method 

is best for seeds large enough to handle easily, and for species that germinate with few problems. Although it is less 

commonly used than the other techniques, direct sowing 

is the standard for most tree species. For less than a few 

thousand seedlings, it’s easiest and quickest to sow by 

hand. Coating seeds with a little baby powder makes them 

easier to sow and easier to see on top of the medium. The 

number of seeds to put into each container will depend on 

the germination expected from the seeds. Use Table 3.2 

for an approximate number of seeds to sow per container 

to end up with 90% or more of your containers with one 

seedling. Ideally, you’d like to minimize the number of 

empty containers, but, as you can see in the example in 

Table 3.3, you reach a point when adding another seed fails 

to result in appreciably more filled containers. You’ll have 

to decide whether seed economy (saving seeds for next 

time) is more important than a few empty cells. Using 

more seeds than is necessary will also require you to do 

more thinning after germination. If you’d like to be more 

precise and don’t mind a little math, the direct calculations 

for determining seeds per container to sow are relatively 

simple and are provided in Appendix 6.3.

Seeds of most species should be barely covered with 

a thin mulch of perlite or coarse grit, with mulch depth 

being no more than twice the thickness of the seeds (see 

Figure 3.7). Make sure the covering material doesn’t have 

too many fine particles that can cause crusting. A good 

mulch keeps seeds from splashing out during watering, 

helps retard algae and moss growth, keeps the surface 

of the medium cool and moist but not wet, and keeps the 

zone around the young stems drier, thus reducing disease 

problems. Seeds that should not be covered include those 

that are very small (for example, sagebrush) or require 

light for germination (for example, birch).

3.3.2.2 Sowing Germinants (15% of Species)—This 

method is recommended for large seeds with deep, complex, 

or unknown dormancy requirements (Table 3.4). Sowing 

germinants is particularly useful for seeds of variable or 

unknown germination. It is a good technique for beginning 

growers because it ensures that a live seed is placed in every 

container and that the crops will grow uniformly. To sow 

germinants, soak your seeds and place them in stratification (if necessary) like you would for a germination test 

(see Section 2.10, Germination Testing). Very large seeds 

(for example, acorns) are mixed with a moist medium such 

as Sphagnum moss, whereas smaller seeds are scattered 

between layers of moist paper towels. Place the seeds in a 

plastic ziplock-type bag, label, and keep in the refrigerator. 

Check the seeds at least weekly and, as soon as the seed 

begins to germinate (Figure 3.18A), place that germinant 

on top of moistened growing medium in the container and 

gently cover with mulch (Figure 3.18B).

Table 3.2—Based on germination of your seedlot, sow the appropriate number of seeds so 90% or more of your 

containers will have at least one seedling.

Seed Percentage of

germination Seeds to sow containers with at

percentage per container least one seedling

90+ 1 to 2 90 to 100

80 to 89 2 96 to 99

70 to 79 2 91 to 96

60 to 69 3 94 to 97

50 to 59 4 94 to 97

40 to 49 5 92 to 97

Table 3.3—A sowing example for a seedlot of common milkweed having 65% germination. Assuming 1,000 seedlings 

are desired, notice that adding more than 3 seeds per container really doesn’t improve the number of containers with seedlings but does waste many seeds. Refer to Appendix 6.3.

 Additional seedlings

Seeds sown Empty Containers with at Seeds Seedlings produced per additional

per container containers least one seedling sown produced 1,000 seeds sown

1 35% 65% 1,000 650 —

2 12% 88% 2,000 880 230

3 4% 96% 3,000 960 80

4 1% 99% 4,000 990 30

5 0% 100% 5,000 1,000 0

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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 43

3.3.2.3 Transplanting Emergents (65% of Species)—

This technique, commonly called “pricking out,” is better 

for small or fragile seeds that would be difficult to direct 

sow or sow as germinants (Table 3.4). The process begins 

with sowing seeds in shallow germination trays or small 

pots filled with a standard peat growing medium that is 

lightly tamped until it is firm, but not compacted (Figure 3.18C). Larger seeds are scattered over the surface of 

the medium by hand, or smaller seeds can be sown with 

a salt shaker with the holes in the top enlarged. The sown 

seeds are covered with a light application of fine-textured 

mulch (unless they are very tiny or need light for germination), irrigated, placed into a greenhouse, and misted 

lightly. Transplanting should be completed as soon after 

germination as possible, especially before the new root 

sends out lateral roots (Figure 3.18C, D, and E). Gently pull 

the germinant from the medium, make a dibble hole in the 

growing medium of an empty container, gently place the 

plant in the hole, firm the medium around the stem, and 

water thoroughly. This procedure sometimes produces a 

“J-root” or kink in the seedling stem; while not as important 

for grasses or many herbaceous plants, this may, for species 

that produce a strong taproot and/or woody species, reduce 

growth in the nursery and/or cause mechanical weakness 

or mortality after outplanting (Figure 3.18F). If the root 

has grown too long to easily transplant, you may reduce 

its length before transplanting, but don’t remove more than 

half of the root. Transplanting germinated seeds or young 

seedlings requires some degree of skill but can be easily 

mastered with a little practice.

Table 3.4—Characteristics of the main seed propagation methods for forest trees and other native plants.

Planting method Best method for: Advantages Disadvantages

Direct seeding: •	 Seeds of medium to •	 Quick •	 Requires seeds of known

large size high quality

Seeds are sown into growth •	 Minimizes seed handling

containers with or without •	 Uniformly shaped seeds •	 Dormant seeds must

treatment with smooth seed coats •	 Mechanical (automated) be treated (or sown

seeding possible containers must be

•	 Seeds of high quality placed into conditions

with viability test •	 Less labor required to meet dormancy

 information requirements)

 •	 Planting occurs all at 

 once •	 Requires thinning and/or

 consolidation for difficult-

 to-germinate seeds

Planting germinants: •	 Very large or irregularly •	 Good growing space •	 Slower and more labor

shaped seeds utilization intensive than direct

Seeds germinating (no leaves seeding

visible) in stratification trays or •	 Seeds of unknown •	 Efficient use of seeds

bags are planted into growth quality or low purity •	 Sowing can take weeks

containers (“sowing sprouts”) •	 Can adjust for unknown or months to complete

•	 Valuable or scarce seed quality

seed lots •	 Crop development will not

	 	 	 	 be uniform because of

•	 Seeds requiring warm staggered sowing

moist treatments or 

stratification •	 Sowing date depends

	 	 	 	 on seed treatment 

 requirements

	 	 	 	 •	 Root deformation possible

 if poorly transplanted

Transplanting emergents: •	 Small or fragile seeds •	 Good growing space •	 Transplanting requires

 utilization skill and is labor intensive

Seeds are sown into trays •	 Seeds of unknown

or pots filled with medium; quality or low purity •	 Efficient use of seeds •	 Difficult to control density

a few days or weeks after in seed trays so disease

germination and when leaves •	 Valuable or scarce seed •	 Can adjust for unknown potential can be high

are present, seedlings are lots seed quality

transplanted into growth •	 Root deformation possible

containers (“pricking out”) •	 More uniform crop if poorly transplanted

 development

Chapter 3—Growing Plants from Seeds
44 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Figure 3.18—Many native plants should be propagated by sowing germinating seeds (A & B), or transplanting young emerging 

seedlings (C & D). Herbaceous species with strong taproots (for example, arrowleaf balsamroot) and woody species (for example, 

longleaf pine) are best transplanted before lateral root development (E), and these transplants should have their roots oriented 

vertically without kinking to avoid root deformation (F).

A B

C D

E F

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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 45

3.3.3 Irrigation and Fertilization

Once your plants are established in their containers, it’s 

time to start watering and fertilizing on a regular basis.

3.3.3.1 Irrigation—You’ll need to water 1 to 3 or more 

times per week, depending on the size of the container, 

media, seedling size, conditions in your propagation environment, and ambient weather. Always water early in 

the morning so that foliage will dry completely during the 

day, reducing disease problems and incidence of fertilizer 

burn.

An easy and repeatable way to determine when to water is 

by using an ordinary bathroom scale. Right before sowing, 

and about an hour after you’ve saturated the medium in your 

containers, weigh the block on a scale. Let’s say it weighs 

26 pounds. This is your “field capacity” block weight; it 

reflects how much water is held in your containers. When 

the weight drops to a certain percentage of field capacity 

weight, it’s time to water your seedlings (Table 3.5). We 

call this target block weight and it changes somewhat with 

the age of your crop. When seedlings are small, it may take 

several days, or even a week, depending on weather to dry 

from saturated to target block weight. Once seedlings are 

larger, however, and depending on your climate, the change 

in block weight from field capacity to target can happen 

often, perhaps every other day or even daily! About once 

every 6 weeks or so, obtain a new field capacity weight 

to compensate for the weight of the seedlings. Note: This 

works well if you have plants in nearly all of the containers. 

If your block of seedlings has many blanks, those will lose 

water more slowly making this technique less useful.

The simplest way to water your seedlings is with a watering can (Figure 3.19A), or a hose-end nozzle (Figure 3.19B). 

Make sure you apply an even amount of water across all the 

containers, and that you apply enough water so that some 

drips out the bottom of the containers. Often containers 

around the edges of the crop will dry down more than those 

in the center and may require additional water. A hose with 

a fine spray nozzle, or even a lawn sprinkler, will also work 

well. If you plan on growing many seedlings, you may wish 

to construct a permanent irrigation system. For any type 

of sprinkler system, check the output to make sure all the 

seedlings receive about the same, and adequate, moisture.

An innovative way to irrigate container plants is known 

as subirrigation, which involves holding plants in a structure 

where they can be watered from below (Figure 3.19C). 

The water is absorbed into the growing media and moves 

upward by capillarity. Subirrigation is particularly useful 

when broadleaved plants get larger and it’s almost impossible to water each container from above because the leaves 

shed the water. It also works very well for growing wetland 

native plants, such as sedges and rushes (Figure 3.19D).

3.3.3.2 Fertilization—Please refer to the fertilizer discussion in Section 3.2.3.1 (Fertilizers: Organic vs. Synthetic) 

because much of that is relevant to growing seedlings in 

containers. For container seedlings, the two options for 

keeping your plants well supplied with nutrients are:

1. Incorporating controlled-release fertilizers into the 

growing media prior to sowing, or top dressing.

2. Liquid feeding or “fertigating” throughout the 

growing season.

For beginners, the best plan may be to use a combination 

of both.

The three nutrients, nitrogen (N), phosphorus (P), and 

potassium (K), are the most important, in terms of amounts 

needed, for healthy shoot and root growth, and are commonly added via fertilizers (Figure 3.20A). N is critical 

for aboveground seedling growth, especially new shoots, 

needles, and buds. Plants lacking sufficient N grow slowly 

or are stunted and have pale green or yellow needles near 

their bases. P is important for root growth and bud development, and K is important for root growth, efficient water 

use by the plant, and improving disease resistance.

Because container seedlings do not have the benefit of 

basic soil fertility and are grown in an artificial media, 

fertilizer application is more critical than with bareroot 

seedlings. On the other hand, this also makes it much easier 

to apply too much fertilizer, resulting in tall, spindly seedlings. Many factors influence how much fertilizer should 

be applied, including the species being grown, container 

size, seedling age, weather, type of medium, and so on.

Table 3.5—An example weekly record of block weights assuming a field capacity block weight of 26 lbs., and 

that seedlings will be watered when target block weight reaches 85% of the field capacity weight 

(26 lbs. x 0.85 = 22 lbs.)

July 22 July 23 July 24 July 25 July 26 July 27

Field capacity weight 26.0 26.0 26.0 26.0 26.0 26.0

Actual weight 22.0 25.0 23.5 20.8 24.5 21.5

Percentage difference 85% 96% 90% 80% 94% 83%

Need to water? Yes No No Yes No Yes

Chapter 3—Growing Plants from Seeds
46 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

3.3.3.2.1 Controlled-Release Fertilizers—These fertilizers generally contain all the macro and micronutrients. The 

fertilizer is encapsulated by a thin, plastic shell that forms a 

round “prill.” The composition and thickness of the shell, along 

with water availability and temperatures, control the rate of 

release of the fertilizer from the prill (Figure 3.20B). Typical 

release rates range from 3 to 18 months. The most effective 

way to apply controlled-release fertilizers is to incorporate 

the prills into the growing medium at label rates when you 

Figure 3.19—Using a watering can (A) or hose-end nozzle (B) 

is the easiest way to water container seedlings. Watering from 

below (“subirrigation”) is effective on larger broadleaved plants 

when it’s ineffective to sprinkle irrigate (C); this method is very 

useful for growing wetland native plants (D).

A

B

C

D

Chapter 3—Growing Plants from Seeds
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 47

are filling the containers. Keep in mind that if you store 

that medium for a length of time before using it, conditions 

may be sufficient for the fertilizer to be released. Prills 

can also be “top-dressed” to individual containers during 

the growing season (Figure 3.20C). Although controlled 

release fertilizers are easy to use, they suffer the drawback 

of not being able to completely control when the nutrients 

become available. This can cause problems, particularly 

when you want to stop height growth and begin dormancy.

3.3.3.2.2 Fertigation—Soluble fertilizers are easily and 

uniformly applied with water. The type and amount of 

fertilizer is discussed in the next section. You can apply 

liquid fertilizers dissolved in water by hand with a watering 

can (Figure 3.19A). A more accurate way to apply liquid 

fertilizers is to use a siphon injector such as the HozonTM 

(Figure 3.20D). The flow of water through the hose causes 

a suction that pulls the fertilizer stock solution up and mixes 

it with the water in the hose at a 1:16 ratio (Figure 3.20E).

You should check the injection ratio of your siphon occasionally. Put a known amount of water into a container 

(this is your “stock solution”), put the siphon hose in it, and 

then measure how much water comes through the hose 

(use a 5-gallon bucket or some other container of known 

volume to measure out flow) until the stock solution container is empty. For example, if you had 1 quart of stock 

solution, and collected 4 gallons (16 quarts) of water while 

waiting for the stock solution to be used up, your siphon 

has an injection ratio of 1:16. In Section 3.3.3.2.4 (Sample 

Fertigation Schedule) you’ll see why this is important. 

Note: Laws require anti-siphon devices on any irrigation 

system connected to a domestic water source. HozonTM 

injectors are designed to prevent contaminated water from 

siphoning back into your drinking water supply.

3.3.3.2.3 Seedling Growth Phases—It’s really difficult to 

give a “recipe” for fertilizing container seedlings because 

different species require immensely different amounts of 

fertilizer, different seed sources for a species may have 

different requirements, and a species requires different 

amounts of fertilizer as it goes through the growing season. Therefore, use the following methods for a conifer 

seedling as a general guide. Be prepared to modify it as 

your seedlings develop.

Use Table 3.6 as a guide to determine how much and how 

often to fertilize. All seedlings have three distinct growth 

phases: establishment, rapid growth, and hardening. During 

each phase, you manipulate fertilizer and water to control 

seedling growth. During the establishment phase, seedlings 

should be well watered (80 to 85% block weights) and receive 

daytime temperatures between 65 to 80 °F and nighttime 

temperatures above 60 °F. This phase lasts about a month 

and helps get seedling root systems started. During the 

rapid growth phase, seedlings receive their highest doses 

of N to encourage height growth. Target block weights are 

still 80 to 85% and temperatures are similar to the initial 

growth phase. Depending on species, the rapid growth 

phase may last from 3 to 15 weeks. When seedlings are 

about as tall as desired, the rapid growth phase ends and 

hardening begins.

Hardening is the most important part of growing 

container seedlings. During the first stage of hardening, 

levels of N in the applied fertilizer solution are greatly 

reduced and target block weights are gradually lowered 

to 60 to 70%. This stage encourages seedlings to decrease 

shoot growth and for some species, stop shoot growth and 

form terminal buds. The appearance of brown buds at 

the tip of the shoot usually takes a few weeks to a month 

or so. Sometimes pines, which usually form terminal 

buds, will form a rosette of dense needles at the tip of 

the shoot. This is okay. Some native plants don’t form 

buds, so your objective is to slow shoot growth and keep 

seedlings stocky.

After a month or so, the objective is to increase seedling 

stress resistance, especially to cold temperatures. Levels 

of N can be slowly increased, but target block weights are 

usually still low (60 to 70%). Increasing N in the applied 

fertilizer helps the seedling increase in stem diameter, form 

a big bud, and continue to develop roots. Temperatures are 

allowed to go to ambient, especially at night, and along with 

the low target block weights help condition the seedling 

for life on the planting site.

So, the general guideline for fertilizing and watering 

low, medium, or fast growing seedlings can be approximated by using Table 3.7. A more advanced guideline 

can be found in Appendix 6.4.

3.3.3.2.4 Sample Fertigation Schedule—Let’s assume 

you’re growing ponderosa pine seedlings. Table3.7 shows 

ponderosa pine is a “medium” grower. Let’s also assume 

the crop is in the accelerated growth phase; Table 3.7 

indicates seedlings with a “medium” growth rate should 

get 130 ppm N. Using Miracle-Gro, Table 3.8 shows 

that we need 1 teaspoon of fertilizer per gallon of water 

to get 130 ppm N. Now let’s assume a few thousand 

seedlings are watered with a hose. Use a siphon injector 

(1:16) to apply 32 gallons of fertilizer solution containing 130 ppm N. That means you’ll need 2 gallons 

of concentrated fertilizer stock solution to run through 

the siphon (32 gallons/16 [the injection ratio] = 2 gallons stock solution). To make the concentrated fertilizer 

solution, mix 32 teaspoons (1 teaspoon for every gallon) 

of fertilizer into 2 gallons of water.

Chapter 3—Growing Plants from Seeds
48 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Figure 3.20—All fertilizers are required by law to show their 

composition of nitrogen (N), phosphorus (P), and potassium (K). 

Controlled-release fertilizer particles (“prills”) consist of soluble 

fertilizers inside thin plastic shells; after water penetrates the prills, 

soluble nutrient ions move outward into the growing medium (B). 

Controlled-release prills can be top-dressed on larger container 

plants (C). The HozonTM (D & E) is a simple fertilizer injector that 

attaches to a garden hose and sucks concentrated fertilizer solution 

and mixes it with water at an approximate ratio of 1 part fertilizer 

to 16 parts water (D & E courtesy of HummertTM International).

A

C

B

Chapter 3—Growing Plants from Seeds

D

E
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 49

Table 3.6—An approximate amount of N in parts per million (ppm) to apply 

to seedlings for each growth phase and an approximate target 

block weight. See Table 3.8 for converting ppm.

Plant Growth Phases

Hardening

Fertilizer Bud Remainder

levels Rapid formation of hardening

(Table 3.7) Establishment growth period period

- - - - - - - - - - - - - - - - - ppm Nitrogen - - - - - - - - - - - - - - - 

Low 33 65 0 33

Medium 65 130 0 65

High 65 200 33 65

Target block 

weights 80% 80% 60 to 70% 75%

Table 3.7—Fertilizer application guidelines for some native plants.

Low Medium High

Grasses and sedges Cow parsnip Huckleberry

Lupine 1 Monarda Whitebark pine

Salvia Chokecherry Pinyon pine

Buffaloberry 1 Cottonwood Interior Douglas-fir 2

Ceanothus 1 Elderberry

Hawthorn Red-oiser dogwood

Sagebrush Serviceberry

Coastal Douglas-fir 2 Jack pine

Quaking aspen Ponderosa pine

1 = Nitrogen-fixing species inoculated with appropriate beneficial microorganism

2 = Ecotype differences

Table 3.8—Teaspoons of Miracid® or Miracle-Gro® to add per 

gallon to achieve desire parts per million (ppm) of 

nitrogen (N) for container seedlings. If you use any 

other type of fertilizer, you’ll need to calculate ppm 

using directions found in Appendix 6.4.

ppm Nitrogen

Teaspoons per Miracid Miracle-Gro

gallon of water 30:10:10 (N:P:K) 15:30:15 (N:P:K)

1⁄4 65 33

1⁄2 130 65

3⁄4 195 98

1 260 130

11⁄2 195

2 260

Chapter 3—Growing Plants from Seeds
50 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Having said all of this, remember that the amount of 

fertilizer you’ll have to apply will depend on the type of 

container, growing medium, and other environmental factors. If seedlings seem to be growing too fast (they’re too 

spindly or flop over when not supported), then reduce the 

rate of fertilizer (less N), or reduce how often you fertilize (every other watering or less). Conversely, if they’re 

growing too slowly, you may increase the rate of fertilizer 

(more N) to encourage growth. It’s extremely important 

to keep detailed records of what you do to your crop and 

how the seedlings grow. Measuring seedling height every 

2 to 3 weeks and matching that to the amount of fertilizer 

applied will help you adjust your fertilizer schedule to 

grow even better seedlings.

3.3.4 Light

As mentioned earlier, most species require full intensity 

sunlight for proper growth and development. That means 

they can’t be grown on a windowsill and it’s not economical to 

raise them with only grow lights. Many species are, however, 

very sensitive to slight changes in daylength. A species like 

interior Douglas-fir grown under normal daylight conditions will form buds before they are as tall as desired. It’s 

fairly easy to “fool” seedlings, however, into “thinking” the 

day is longer by providing some periods of light to break 

up the night. A single 300-watt bulb suspended 4 to 5 feet 

above the crop for every 60 to 80 square feet of containers 

is sufficient light. The easiest way to “fool” your seedlings 

is to put the light on a timer set to come on before sundown 

and to extend the length of day to 18 or 20 hours. Once your 

seedlings are as tall as you’d like them, turn off the light. 

The abrupt change in daylength, along with changes in 

target block weight and fertilization rate, will encourage 

your crop to cease shoot growth and form buds.

3.3.5 Hardening

Once your plants have reached the desired height, it’s time 

to harden your crop. Hardening means slowing their growth 

rate and getting them ready for the cooler temperatures of 

fall and winter. The first step in hardening is to reduce irrigation to stress the plants slightly. If you have your plants in a 

greenhouse or cold frame, the next step to induce hardiness 

is to expose your plants to full sunlight (the exception being shade-loving plants), wind, and ambient temperatures. 

Induce a mild nutrient stress by first leaching the growing 

medium with water, and then reducing the amount of fertilizer you are applying, especially nitrogen. You should be 

able to see some color changes in the foliage and the leaves 

or needles should feel tougher to the touch. The leaves of 

deciduous plants will become yellow and eventually drop. 

These changes are desirable and mean that your crop is 

ready for outplanting or overwintering.

3.3.6 Pest Management

Disease can occur rapidly in a crop of container seedlings 

because the nursery environment is also conducive to 

diseases. Sanitation is key to minimizing disease problems. Always remove diseased material immediately 

and either burn it, bury it, or send it away in the trash.

The first disease you may encounter is damping-off 

(see text box on page 32). It affects germinating seeds 

and very young seedlings. Damped-off seedlings tip over 

at the ground line and shrivel up. You can help prevent it 

by watering sparingly when seedlings are small, and by 

quick removal of dead and dying seedlings. The second 

important disease is root rot, and it usually becomes a 

problem when seedlings are larger. Seedlings turn brown, 

often from the top of the stem. Generally, once you see 

symptoms, it’s too late to do much about it. Root rot can 

be prevented by using clean containers, proper watering, 

and keeping seedlings and their roots from getting too 

hot. Use a 1 inch by 6 inch piece of wood laid on end 

to shade the edges of blocks exposed to direct sunlight.

At the end of the growing season Botrytis disease is often 

a problem. The fungus Botrytis forms a gray web-like growth 

on needles, eventually infecting seedling stems and causing 

death. Botrytis generally becomes a problem when foliage 

from one seedling touches foliage from another seedling. 

The fungus gets its start on dead foliage and disease is 

favored by cool temperatures and high humidity. Botrytis 

disease can be controlled by proper watering, removing 

dead and dying seedlings as you see them, and brushing 

foliage after watering. A piece of PVC pipe works well as 

a brush, but be gentle so shoots aren’t damaged. During 

hardening, you can also spread seedlings out to encourage 

air movement between them, thus reducing disease. If you’re 

using Ray Leach cells or peat pellets, you can rearrange 

them to have an empty row between rows of seedlings.

One last problem with container seedlings is fungus gnats. 

These small, dark flies are more nuisance than problem, 

although in large enough quantities their larvae will feed 

on seedling root systems and can kill seedlings. They’re 

usually more troublesome when seedlings are watered too 

often, and their populations soar if you have a lot of moss 

and algae, especially in blank cells. Fungus gnats are best 

controlled through proper irrigation. Yellow sticky cards, 

which are available through garden catalogs, trap the insects 

and make you aware of a potential problem. Place the cards 

at or near the surface of the containers and when the flies 

land on it, they become entangled. The cards work best 

when laid flat.

3.3.7 Beneficial Microorganisms

Because container plants are growing in an artificial 

growing medium, some native plants will benefit from 

Chapter 3—Growing Plants from Seeds
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 51

inoculation with mycorrhizal fungi or nitrogen-fixing 

bacteria (see Section 3.2.3.3, Young Seedlings: Establishing 

Your Crop). Inoculation should not be seen as a “magic 

bullet” but as a way to make good plants better. Because 

large amounts of fertilizer generally inhibit mycorrhizal 

formation, it’s usually best to wait to inoculate until the 

hardening period. Inoculation with beneficial microorganisms is a complicated subject and the benefits vary from 

species to species, so do some research online or check 

with a native plant nursery for advice.

3.3.8 Harvesting, Handling, and Storage

The outplanting season, or “window,” will determine 

when seedlings are harvested (“lifted”), handled, and stored. 

Properly hardened seedlings can be planted whenever adequate site conditions exist (good soil moisture and warm 

soil temperatures). In the southeastern U.S., seedlings can 

be outplanted from late fall through early spring. At more 

northerly latitudes or at higher elevations in the western U.S., 

seedlings can be planted during fall if good soil moisture 

and warm soil temperatures are present (see Section 5.2, 

Outplanting Windows). If the end of seedling production 

coincides with a good outplanting window (for example, 

seedlings are hardened in fall and the outplanting site has 

good soil moisture), then seedlings can be pulled directly 

from containers and immediately outplanted without storage.

If, however, properly hardened seedlings must be held 

during the winter until the outplanting site is ready, then 

seedlings will need to be stored. Plants growing in an enclosed structure can be kept in their containers until about 

mid-November through mid-December. Keep the plants as 

cold as possible, but try not to let the root plugs freeze by 

placing the containers close together on the ground, and 

insulating around the roots with sawdust or StyrofoamTM 

panels. A few gentle freezes of 28 °F or higher are probably okay, especially if you’ve exposed seedlings to cold 

temperatures before freezing. However, seedlings suddenly 

exposed to a drastic drop in temperature can be damaged 

or even killed. Then, if you have access to refrigeration, 

seedlings should be removed from their containers in 

mid-December to mid-January, enclosed in plastic bags, 

and kept at 28 to 34 °F until you are ready to plant them. 

Seedlings can be stored in this manner for up to 6 months. 

Thaw frozen seedlings slowly, at low temperatures, and out 

of direct sunlight before planting. If you don’t have access 

to refrigerated storage, keep your plants in a cool, shady, 

protected location, such as a shade-frame or lath house. In 

open storage, plants may need to be irrigated during warm 

or windy periods in the late winter and early spring.

Regardless of storage method, check seedlings often 

for molds. Storage molds usually begin growing on dead 

foliage. Therefore, when you put seedlings into storage, 

remove any dead foliage. Storing seedlings in an upright 

position also helps reduce mold problems. Remove moldy 

seedlings immediately.

3.3.9 Holding Seedlings Over

If your seedlings have sufficient roots to be pulled 

from the containers but are too small to plant, you have 

two options: transplanting into larger containers or growing them as bareroot transplants. Seedlings at this stage 

cannot be held over in the same container for a second 

growing season because they become rootbound. Unless 

transplanted, seedlings will have too many roots for the 

container and won’t grow well after outplanting. Seedlings 

can be transplanted into larger containers anytime from 

fall to spring.

3.3.10 Cleaning Containers Between Crops

In between crops, containers should be thoroughly 

cleaned of old growing medium, algae, and other debris. 

Fungal spores can still remain after vigorous cleaning, however, waiting to infect your next crop. Dipping containers 

in very hot water (160 to 180 °F degrees) for 15 seconds 

to 2 minutes (depending on the temperature and type of 

container) will kill nearly all the fungal spores. Soaking 

containers in a 10% bleach solution and then rinsing with 

fresh water is also effective.

3.4. Additional Reading.

Jacobs, D.F.; Landis, T.D. 2008. Fertilization. In: Dumroese, R.K.; 

Luna, T.; Landis, T.D., eds. Nursery manual for native plants: a 

guide for tribal nurseries. Volume 1, Nursery management. Agric. 

Handb. 730. Washington, DC: U.S. Department of Agriculture, 

Forest Service: 200-215.

Jacobs, D.F.; Landis, T.D.; Luna, T. 2008. Growing media. In: Dumroese, R.K.; Luna, T.; Landis, T.D., eds. Nursery manual for native 

plants: a guide for tribal nurseries. Volume 1, Nursery management. 

Agric. Handb. 730. Washington, DC: U.S. Department of Agriculture, 

Forest Service: 76-93.

Jacobs, D.F.; Landis, T.D.; Luna, T. 2008. Propagation environments. 

In: Dumroese, R.K.; Luna, T.; Landis, T.D., eds. Nursery manual 

for native plants: a guide for tribal nurseries. Volume 1, Nursery 

management. Agric. Handb. 730. Washington, DC: U.S. Department 

of Agriculture, Forest Service: 54-75.

Landis, T.D.; Wilkinson, K.M. 2008. Water quality and irrigation. In: 

Dumroese, R.K.; Luna, T.; Landis, T.D., eds. Nursery manual for 

native plants: a guide for tribal nurseries. Volume 1, Nursery management. Agric. Handb. 730. Washington, DC: U.S. Department of 

Agriculture, Forest Service: 176-199.

Luna, T.; Landis, T.D.; Dumroese, R.K. 2008. Containers. In: Dumroese, 

R.K.; Luna, T.; Landis, T.D., eds. Nursery manual for native plants: 

a guide for tribal nurseries. Volume 1, Nursery management. Agric. 

Handb. 730. Washington, DC: U.S. Department of Agriculture, 

Forest Service: 94-111.

Luna, T.; Wilkinson, K.M.; Dumroese, R.K. 2008. Seed germination 

and sowing options. In: Dumroese, R.K.; Luna, T.; Landis, T.D., 

eds. Nursery manual for native plants: a guide for tribal nurseries. 

Volume 1, Nursery management. Agric. Handb. 730. Washington, 

DC: U.S. Department of Agriculture, Forest Service: 132-151.

Chapter 3—Growing Plants from Seeds
52 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Chapter 4. Growing Plants 

From Cuttings

Many native plants can be grown from cuttings. Cuttings are portions of plants (stems, leaves, roots) that when 

treated and planted will develop into new plants complete 

with stems, leaves, and roots. Although shoots, roots, bulbs, 

corms, tubers, and rhizomes all offer possible material to 

reproduce plants, shoots are perhaps the most commonly 

used for vegetative propagation. These vegetative propagules (see Section 1.3, Seeds and Other Propagules) can 

be collected from wild plants or from plants specifically 

maintained at the nursery for this practice. You may want 

to grow plants from cuttings, particularly if the plant is 

difficult to propagate from seeds or if the desired plant 

has an unusual growth habit or flower color. Using cuttings 

maintains these desired tracts because, as we discussed 

in Section 1.3 (Seeds and Other Propagules) and showed 

in Figure 1.5, all new daughter plants that arise from cuttings are genetically identical to the parent plant. Another 

advantage is that sometimes using cuttings will result in a 

larger plant in a shorter time than the plants can be grown 

from seeds. A disadvantage is that cuttings generally 

require more care and can be more expensive to produce 

than plants from seeds. If you plan to grow plants from 

cuttings, follow the procedures described below to ensure 

success.

4.1 Shoot Cuttings

Although cuttings can be taken from a variety of plant 

parts, using portions of the shoots is the most common 

method. Some species, such as cottonwood and willow, 

have shoots containing pre-formed roots, an adaptation to 

living near streams, and therefore are very easy to root. 

Most species lack this adaptation and must be given special treatment before roots develop. Cuttings are classified 

as hardwood, softwood, or semi-hardwood (Figure 4.1) 

depending on when they are collected.

Hardwood shoot cuttings are collected during the winter 

dormant season. Softwood cuttings, which includes cuttings of herbaceous plants, are collected in the spring and 

early summer when shoots are actively growing and leaves 

are present. Semi-hardwood cuttings are collected in late 

summer and early fall when shoot tissue has hardened and 

terminal buds are set.

4.1.1 Hardwood Cuttings

Hardwood cuttings are collected during the winter 

dormant season. Many woody species can be grown from 

hardwood cuttings. With easy-to root species, like willow 

and cottonwood, you can collect shoot cuttings that are 

large or small, depending on how you are using them. 

Large cuttings of willows and poplars, or “live stakes,” can 

be outplanted directly, foregoing any time in the nursery 

(Figure 4.2A). Smaller cuttings (2 to 6 inches long) are used 

for propagation in the nursery. Some native plants, such 

as juniper, rhododendron, and manzanita (Figure 4.2B & 

C), may be easier to grow from cuttings than from seeds. 

Species other than the willows and cottonwoods typically 

require treatment with a rooting hormone, and even then, 

may require several weeks or even months before roots 

appear. Placing the cuttings in hot frame or rooting chamber usually improves rooting success (see Section 4.3.3, 

Rooting Environment).

4.1.2 Softwood Cuttings

Softwood shoot cuttings are prepared from the new, 

succulent growth of herbaceous and woody deciduous or 

evergreen species. They generally require more attention, 

treatment with rooting hormones, and a specialized propagation environment. For woody plants, the best softwood 

cutting material has some flexibility but is mature enough 

to break when bent sharply (Figure 4.2D); avoid using the 

extremely fast-growing, tender shoots.

Figure 4.1—Hardwood cuttings are collected during winter 

dormancy. In late spring and early summer, softwood cuttings 

are taken from new shoots that bend but do not break. Cuttings 

of non-woody herbaceous plants are considered softwood as 

well. Semi-hardwood cuttings come from hardened stems later 

in the growing season.

Chapter 4—Growing Plants From Cuttings
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 53

4.1.3 Semi-Hardwood Cuttings

As the name implies, this type of cutting is intermediate between the succulent growth of a softwood 

cutting and the completely dormant stage of a hardwood cutting. Semi-hardwood (or greenwood) cuttings are usually taken from woody species during 

the late summer and early fall after the last flush of 

growth and as the wood is partially mature, often with 

a terminal bud present for the next growing season 

(Figure 4.2F).

4.2 Collecting and Storing Shoot Cuttings

Regardless of when you collect cuttings, some important 

points must be remembered. As with seeds, collect cuttings 

near the area where you intend to outplant them to 

ensure they are properly adapted to the environment (see 

Section 2.1.2, Seed Source). A good cutting will always 

consist of healthy stem tissue with some intact buds or leaves, 

and with enough stored food reserves to sustain it until 

new roots are formed. Also recall that for dioecious 

species (see Section 1.3, Seeds and Other Propagules), 

Figure 4.2—Types of cuttings. Large, dormant hardwood cuttings (“live stakes”) of willow and cottonwood can be stuck directly 

into the soil on the outplanting site without any nursery culture (A). Other hardwood cuttings, such as bearberry (B & C), require 

rooting hormones and special propagation structures. Softwood cuttings of woody plants have some degree of flexibility but are 

mature enough to break when bent sharply (D). Rooted softwood snowberry shoot cutting (E). Semi-hardwood cuttings, collected 

from lateral branches, should have a maturing terminal bud when collected in late summer (F).

A

D E

B

C

F

Chapter 4—Growing Plants From Cuttings
54 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

such as willow, cottonwood, and buffaloberry, individual 

plants are either male or female (Figure 1.5), requiring you 

to identify the sex of the parent plant in advance to ensure 

that you collect both male and female cuttings. Where you 

collect the cutting on a plant can also influence your success.

Older, large woody plants, such as shrubs and trees, are 

composed of two types of tissue: juvenile and mature. Cuttings from the juvenile parts of plants root much more easily 

than those from mature tissue, which produces flowers and 

fruits. In some plants, juvenile tissue can be distinguished 

from the adult phase by differences in leaf shape or color, 

and the overall habit of the plant. This is easily seen in 

junipers, where juvenile leaves are feathery and needlelike and often differ in color from mature leaves that are 

more rounded at the tips that bear cones. In other conifers, 

juvenile wood is usually found on the lower portion of the 

tree crown. In deciduous plants, juvenile wood is found 

near the stem base or root crown and can be discerned 

as “sucker” shoots (Figure 4.3A). In some extreme cases, 

difficult-to-root species will only root from stems collected 

from young seedlings. One way to ensure a good source 

of juvenile material for cuttings is to grow a few “mother 

plants” at your nursery that can be trimmed regularly to 

produce long, straight juvenile cuttings. “Donor plants” in 

natural stands can also be selected for hedging on an annual 

basis if cuttings will be collected from the area for several 

years. Note however, cuttings taken from mature lateral 

branches of trees will often continue to grow sideways. 

Therefore, collect cuttings from upright branches to obtain 

upright plants in the nursery (Figure 4.3B).

4.2.1 Cutting Size, Labeling, and Temporary 

Storage

When collecting cuttings from donor plants, make a cut 

just below a node; rooting is more likely to occur there. 

Make sure that some buds or leaves are present. The best 

size of cutting varies from species to species and the 

time of year it is collected. Small micro-cuttings, typically less than 2 inches long but having at least a bud, 

can be taken from easily rooted species (Figure 4.4A). 

Most other species, however, are rooted from cuttings 

that are 4 to 18 inches long and contain at least two buds 

(Figure 4.4B). Don’t worry about making the cuttings to 

exact sizes in the field; just cut them half again as long as 

you think you’ll need and trim them to desired size back 

at the nursery. Try to collect cuttings during mornings on 

cloudy, cool, humid days so the donor plants and cuttings 

are subject to less stress. Immediately place cuttings inside 

white plastic bags that don’t allow sunlight to penetrate, 

label them noting origin and date, and place them in a 

cooler with some “blue ice” (Figure 4.4C & D). Never 

expose bags of cuttings to full sun.

Figure 4.3—The part of the plant where you collect your 

cuttings is important. Although counterintuitive, the fact is that 

cuttings collected from the lower parts of large woody plants 

root easier than those higher up (A). With most woody plants, 

especially trees, cuttings should be collected from upright 

branches (B, left) or they may grow sideways after rooting 

(B, right).

A

B

Chapter 4—Growing Plants From Cuttings
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 55

4.2.2 Storing Cuttings at the Nursery

Back at your nursery, deciduous hardwood cuttings should 

be wrapped in moist paper towels, peat moss, or burlap 

before being placed into refrigerated storage. Depending 

on species, cuttings can be stored for several days, weeks, 

or even months. Inspect stored cuttings frequently to ensure 

they are slightly moist and mold-free. Conifer hardwood 

cuttings, softwood cuttings, and semi-hardwood cuttings, 

because they have foliage, must be treated promptly and 

struck (that is, inserted) into the medium used to root them.

4.3 Rooting Shoot Cuttings

Because of their open wounds, cuttings are very susceptible to diseases. So, while preparing cuttings for planting, 

Figure 4.4—Small “micro cuttings” are suitable for easy-to-root species (A), but most cuttings for most species should be 4 to 18 

inches and contain at least two lateral buds (B). Hardwood cuttings collected during winter are dormant and hardy, but nondormant 

softwood cuttings must be handled more carefully (C). Your cutting collection kit should include “blue ice” and a cooler to keep 

cuttings cool during harvest and transportation (D).

it is important to keep the work area sanitized by using 

a disinfectant like household bleach (Figure 4.5A) mixed 

1 part bleach to 9 parts water. Use sharp, well-maintained 

shears and knives to make clean cuts, and disinfect them 

often with alcohol. Trim cuttings to a standard size and 

shape, which promotes side shoots and eliminates shoot 

tips that could die back during rooting. Leafy cuttings 

should have about one-third to one-half of the foliage 

removed to minimize water loss from the cutting. It is 

very important, however, to have some leaves so that 

the cutting can photosynthesize during rooting.

Shoot cuttings can be either directly struck (that is, inserted) into individual containers used to grow them to their 

final size, or into communal trays in a rooting chamber 

from which they will be transplanted once they form roots. 

B

A

C

D

Chapter 4—Growing Plants From Cuttings
56 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Easy-to-root hardwood cuttings can be struck directly into 

containers without any treatment or special environment. 

Most other species must be treated with hormones, struck 

into special media, and placed into a special propagation 

environment.

4.3.1 Rooting Hormones

Auxins are natural plant hormones that encourage 

root formation. Two common types are IAA (indole-3-

butyric acid) and NAA (naphthaleneacidic acid). Although 

natural sources of auxins can be used, nurseries rely on 

synthetic sources because of purity, higher concentrations, 

and availability of ready-to-use liquid and powder forms, 

and because some preparations also contain fungicides 

(Figure 4.%B). Synthetic hormones can be purchased at 

specific concentrations (either expressed in parts per million 

or as a percentage) or you can mix your own to specific 

concentrations. The best type of auxin, IAA or NAA, or 

relative combination of auxins and their application rates 

will vary among species.

4.3.2 Rooting Media

An ideal rooting medium provides a good balance of 

aeration and moisture but is firm enough to support the 

cuttings. The optimum pH is 5.5 to 6.5 for most plants, but 

acid loving plants prefer a pH of 4.0 to 5.0. Some common 

components of rooting media generally include a combination of two or more of the following: large grade (#2) 

perlite, pumice, Sphagnum peat moss, coarse sand, and 

fine bark chips. Different combinations of the components 

are used depending on the species being propagated, but 

perlite is one of the most common ingredients in rooting 

media. Avoid very fine or very coarse grade sands because 

they tend to discourage root development, and roots that 

do form tend to be brittle and break off. Formulating a 

good rooting medium promotes development of fibrous root 

systems that retain a quantity of the rooting medium during 

lifting. This aids in establishment by reducing chances of 

transplant shock during transplanting.

4.3.3 Rooting Environment

Cuttings need moderate light levels so that their foliage 

can continue to photosynthesize and produce the necessary 

energy and hormones that stimulate rooting. Unfortunately, 

shoots and leaves of cuttings lose water as they photosynthesize, but lacking roots, the cuttings cannot replace that 

lost water. Therefore, you must keep the humidity around 

them high to reduce water loss. A good rooting environment 

protects the cuttings from excessive sunlight, wind, and 

precipitation and keeps the humidity around the cuttings 

high. Although a plastic bottle will work for an individual 

cutting (Figure 4.5C), or a plastic tent for a few seedlings, 

a hot frame is more appropriate if you plan to root any 

cuttings. Because the temperature can increase rapidly 

inside any rooting environment, diligent daily inspection 

is required to ensure proper rooting conditions. Frequent 

light waterings with a misting nozzle are recommended to 

keep humidity high. If large numbers of cuttings are being 

rooted, an automated misting system can reduce the labor 

required. In general, cuttings should not be fertilized until 

after roots form, but cuttings that take a long time to root 

may benefit from a dilute liquid fertilizer application. Many 

species root better if the rooting medium is warmer than 

the air, so some growers place heating cables underneath 

the flats of cuttings.

4.4 Transplanting

Transplanting is always one of the major stress periods 

during nursery culture, and transplant shock is even greater 

with rooted cuttings. Therefore, prepare containers, media, 

labels, wet paper towels, and transplanting tools ahead of 

time. Fill the containers about halfway, and water so that 

the growing medium is “moist, but not wet.” Transplant 

rooted cuttings early or late in the day while keeping them 

out of direct sunlight. More than likely, all of your cuttings will not all be ready to transplant at the same time. 

Hold the cutting gently by the stem, carefully remove it 

from the rooting media without disturbing any media that 

remains attached to the roots, examine the root development, and select only those with an adequate root system 

(Figure 4.5D). Loosely wrap a moist paper towel around 

the root systems and keep the cuttings in the shade until 

they are transplanted. Hold the rooted cutting by the stem, 

insert it into the half-full container, and then backfill around 

the root system with moistened growing medium. Gently 

tamp the medium around the plants and then label, water, 

and move them to the growing area.

If cuttings lack a good root system by the end of summer, 

they should be left in the rooting media and transplanted 

the following spring. These cuttings should be hardened, 

as described above, at least 6 weeks before the first frost.

If, during fall, cuttings are just beginning to form new 

roots, these cuttings will need extra protection during the 

winter. Ideally, the root temperature should be kept at 34 

to 41 °F. Placing cuttings inside a well-insulated cold frame 

works well.

4.5 Other Propagules Used in 

Vegetative Propagation

Bulbs, tubers, corms, and rhizomes are specialized plant 

structures that function in the storage of food, nutrients, and 

water. Bulbs are underground storage organs consisting 

of a short fleshy stem surrounded by fleshy modified 

Chapter 4—Growing Plants From Cuttings
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 57

Figure 4.5—Sanitation is critical while preparing cuttings for 

striking, and a dilute solution of household bleach is an excellent 

disinfectant (A). Most cuttings require treatment with special 

rooting hormones (B) and a protected environment to keep 

humidity high (C). Cuttings will develop roots at different rates, 

so transplant only those with adequate roots (middle and right) 

and return the others to the rooting chamber (D).

leaves (scales). Tunicate bulbs have outer scales that are 

dry and membranous that can be used for propagation 

(Figure 4.6A). Corms are very similar to tunicate bulbs 

and are comprised of a swollen stem base enclosed by 

the dry scale-like leaves (Figure 4.6B). Cormels are 

miniature corms that form between the old and new 

corms which, because of their small size, require more 

time in the nursery to produce an acceptable plant for 

outplanting. Tubers, like the common garden potato, are 

swollen modified stems that serve as underground storage organs, and the “eyes” are actually nodes containing 

buds. Propagation by tubers involves planting the entire 

tuber or dividing it into sections containing at least one 

eye. Rhizomes are specialized stems in which the main 

axis of the plant grows horizontally or vertically at or 

below the soil surface. Many herbaceous plants and 

woody shrubs can be easily propagated with rhizomes 

(Figure 4.6C). Rhizomes are cut into sections containing 

some roots and at least one shoot or bud; these “divisions” can then be planted in containers or bareroot 

beds. Many herbaceous forbs, grasses, and grass-like 

plants can be multiplied by dividing their crowns; crown 

division is usually done just before shoot growth begins 

in the spring. Plants are dug up and the crown cut into 

sections that contain a substantial portion of the root 

system; these divisions are then planted into containers or bareroot beds. Plants that produce runners, like 

strawberries, can be propagated by cutting the nodal 

sections of the runners containing roots, and planting 

them (Figure 4.6D).

4.6 Post Transplanting Care

Transplanted cuttings should be placed in a shaded, 

protected area of the nursery. During the next month or so, 

cuttings should be hardened by exposing them to progressively more sunlight by moving them to different areas of 

the nursery. Be vigilant to ensure the rooted cuttings are 

not stressed. Once the rooted cuttings have acclimated to 

conditions outside the rooting environment, they can be 

cultured in the same manner as container seedlings (see 

Chapter 3).

A

D

B C

Chapter 4—Growing Plants From Cuttings
58 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Figure 4.6—In addition to shoot cuttings, native plants can also be propagated using other vegetative structures, 

such as bulbs (A), corms (B), rhizomes (C), and runners (D).

4.7 Additional Reading

Cullina, W. 2000. Growing and propagating wildflowers of the United 

States and Canada. The New England Wild Flower Society. New 

York: Houghton Mifflin Company. 322 p.

Landis, T.D.; Tinus, R.W.; Barnett, J.P. 1999. The container tree nursery 

manual. Volume 6, Seedling propagation. Agric. Handb. 674. Washington, DC: U.S. Department of Agriculture, Forest Service. 167 p.

Luna, T. 2008. Vegetative propagation. In: Dumroese, R.K.; Luna, 

T.; Landis, T.D., eds. Nursery manual for native plants: a guide for 

tribal nurseries. Volume 1, Nursery management. Agric. Handb. 

730. Washington, DC: U.S. Department of Agriculture, Forest 

Service: 152-175.

A C

B D

Chapter 4—Growing Plants From Cuttings
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 59

Chapter 5. Outplanting

5.1 Care During Outplanting

Nursery plants are in a period of high risk from when 

they leave the protected environment of the nursery to 

when they are outplanted. It is important to remember that 

nursery plants are alive and perishable, and therefore should 

be treated with utmost care at all times. Stressful injuries 

incurred between harvesting and outplanting, however, 

are often not evident until several weeks or even months 

after planting. Because all types of abuse or exposure are 

cumulative, it is helpful to think of native plant quality as 

a checking account. Immediately before harvesting, plants 

are their maximum quality (100%), but all subsequent 

stresses are withdrawals from the account (Figure 5.1). It 

is impossible to make a deposit—nothing can be done to 

increase plant quality after leaving the nursery.

Temperature stress is important because warm seedlings 

use stored energy that could be used for growth after outplanting. It’s best to keep seedlings cool, shaded, and out 

of the wind right up until the moment you outplant them. 

On the outplanting site, temporarily store seedlings in a 

snow bank, a cooler, or at least in deep shade. Don’t set 

them in full sun. Be careful with tarps. Placing most types 

of tarps on top of seedlings to shade them from sun actually makes them warmer than being in direct sunlight. If 

you use a tarp, select one made of reflective material and 

suspend it at least 3 feet above the seedlings so air will 

circulate between the tarp and the seedlings. Remove only 

as many plants as you can install in an hour or two.

5.2 Outplanting Windows

Years of experience have proven that, in general, the best 

time to outplant most native plant nursery stock is when 

they are dormant and least susceptible to the stresses of 

harvest, storage, shipping, and planting. The outplanting 

window is defined as the period of time during which 

environmental conditions on the site most favor survival 

and growth of nursery stock, and it varies considerably 

across the country (Table 5.1). Therefore, you should give 

some thought to what factors would be most limiting 

where you will be outplanting your plants. Although soil 

moisture and temperature are the usual constraints on 

most sites (Figure 1.1A), other environmental or biological factors can also limit plant survival and growth. For 

example, animal predation by rabbits and deer can be the 

most limiting factors to outplanting success.

Although good quality, nursery plants can be outplanted 

almost any time of year, the primary outplanting windows 

are in spring or fall in more northerly latitudes, as well as 

throughout the winter months in the southeastern United 

States. Fall-planted seedlings should go into the ground 

when enough soil moisture is available to support them, 

provided seedlings will have 6 to 8 weeks or so to grow 

roots before winter weather begins. That root growth makes 

them less likely to frost-heave and suffer from winter desiccation. Fall-planted seedlings have an extra advantage 

of beginning root growth in the spring before you could 

typically outplant. This extension of the growing season 

improves first year survival and growth.

In spring, seedlings should be outplanted when the 

ground has dried enough to dig a proper hole. If the soil is 

too wet you may cause serious soil compaction and restrict 

seedling root growth. Here’s an easy way to see if your soil 

is too wet: dig a hole, then shovel the soil back into the 

hole—if the soil doesn’t fit easily back into the hole, it’s 

too wet. The earlier you can plant, the better; early spring 

planting allows seedlings to take full advantage of the 

growing season and available water.

Figure 5.1—Think of native plant quality as a checking account 

in which all types of abuse or stress are withdrawals. Note that 

all stresses are cumulative and no deposits can be made—it 

is impossible to increase plant quality after you harvest them.

Chapter 5—Outplanting
60 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

5.3 Outplanting Tools and Techniques

Your plants will have the greatest chance of surviving 

and growing if you select the best possible location for 

outplanting. Be sure to consider the natural habitat of your 

plant—does it occur on well-drained, upland sites or wetter bottom sites? Although a planting location may seem 

exactly the same, there are “microsites” where conditions 

are better. Exposure to afternoon sun can generate severe 

moisture stress, especially before the plant has had time 

to extend new roots out into the soil. So, look for places 

with natural shade such as the north and east sides of 

downed logs, stumps, or large rocks. Slight soil depressions 

where rainfall can accumulate are good planting sites for 

upland species, but don’t plant them in low areas where 

water will stand for any amount of time. Compacted soil 

is detrimental because all the large pores spaces for water 

and air exchange have been squeezed out, so avoid ruts or 

other areas where vehicles have traveled.

Nursery stock can be outplanted with a variety of different tools but the objective is to safely and efficiently dig 

a hole deep enough to allow proper root placement without soil compaction. Planting bars or dibbles require the 

least effort but, because no soil is actually removed, they 

compact the soil to the sides and bottom of the hole. In 

clay soils, this compaction seriously reduces new root 

growth. Planting bars and dibbles are popular, however, 

when installing wetland plants. For upland plants, the best 

all-around planting tool is a shovel. Root plugs on nursery 

stock used for reforestation or restoration are longer and 

narrower than plant materials used for landscaping and 

gardening, so specialized planting tools have been developed. Planting shovels are tile spades that have blades 

that are long enough to match the depth of the plant root 

system (Figure 5.2A). Padded foot rests and reinforced 

blades make it much easier to penetrate the soil and lever 

back and forth to create the hole.

Whatever outplanting tool is used, the hole should be 

dug deep enough to so that it is deeper than the full length 

of the root plug. Once the hole is excavated to the proper 

depth, hold the plant vertically slightly below ground level 

and gradually backfill mineral soil by hand around the root 

plug (Figure 5.2B), gently tamping to remove air pockets. 

This ensures good root-to-soil contact that enables plants 

to access water and nutrients. A well-planted seedling 

is not outplanted too deep or too shallow; no foliage is 

buried; the orientation is straight, especially on steep 

ground; planting holes are backfilled with mineral soil, 

(avoiding grass, sticks, rocks, or snow) that is gently 

tamped to remove air pockets (Figure 5.3).

Table 5.1—If site conditions are favorable, container plants can be outplanted year-round. Here are some potential outplanting 

windows; not every potential window is presented. 

Region Potential outplanting windows Outplanting conditions

Great Lakes states April and May Typical spring outplanting

Rocky Mountains June and July Good soil moisture and warmer soil temperatures;

(higher elevations) spring access prohibited by snow

Southwestern U.S. August Coincides with summer rains

Northern California September and October Adequate soil moisture exists and spring outplanting

is hampered by poor access

Southeastern U.S. November through February Outplanting conditions favorable throughout winter

Pacific Northwest (coastal) February through March Typical spring outplanting

Chapter 5—Outplanting
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 61

Figure 5.2—The best planting tool for all types 

of plants and soil conditions is a shovel with 

a long narrow blade that is as deep as the 

root plug (A). Once the hole is deep enough, 

suspend the plant with roots in a vertical plane 

and fill around them with soil, gently tamping 

the soil to prevent air pockets (B).

Figure 5.3—Nursery stock should be planted 

properly (A). Common problems include 

planting too shallow (B), planting too deep 

(C), improper vertical placement (D), filling the 

hole with debris (E), or poor compaction that 

leaves air pockets around the root plug (F).

A

B

Chapter 5—Outplanting
62 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

5.4 Care After Outplanting

Now that the plants are in the ground, you can promote 

greater survival and growth by addressing four important 

factors: water, fertilization, weeds, and animals.

5.4.1 Water

Native plants are resilient and well-adapted to their environment. If grown well, properly hardened, and outplanted 

correctly in the absence of weeds, most species should 

survive and grow well without supplemental water. They 

will, however, respond if provided additional water after 

outplanting, especially during hot weather. If you decide to 

water plants after outplanting, remember that how often 

you need to water will depend on the soil and weather. 

Sandy soils don’t retain moisture well so you’ll have 

to water more often. On the other hand, clay soils hold 

moisture very well so you may not need to water for 2 or 

3 weeks after a thorough watering. Water long enough 

to thoroughly moisten the root zone and encourage deep 

rooting (Figure 5.4B). If you are installing a windbreak 

of native trees and shrubs, a drip irrigation line is the 

most efficient way to water seedlings because it delivers moisture directly to each plant in a controlled and 

consistent manner—less water is wasted to run-off or 

evaporation. Stop watering about 1 month before the 

first frost.

5.4.2 Fertilization

Controlled-release fertilizers can be applied at the time 

of outplanting, either in the hole, in a dibble hole next 

to the plant, or around the base of the plant. In general, 

placing the fertilizer in a dibble hole alongside the plant 

makes the most sense because it reduces the possibility of 

fertilizer burn to roots and prevents nutrients from being 

“stolen” by competing vegetation. If you are watering your 

plants, it would be easy to dissolve soluble fertilizers in 

the solution (see Section 3.3.3.2.2, Fertigation); liquid 

fertilization ensures quick uptake and prevents possible 

fertilizer burn.

5.4.3 Weeds

Native plants grow better when weeds are controlled 

because weeds out-compete desired plants for water 

and nutrients. Good weed control greatly reduces the 

need for adding extra water and fertilizer. For reforestation, 

when outplanting on recently harvested sites, weeds generally aren’t a major problem, although resprouting brush 

can limit seedling survival and growth. Planting former 

agricultural land is probably the worst-case scenario for 

weeds; maintain at least a 3 feet by 3 feet weed-free 

square around each plant for at least the first 2 to 3 years; 

The following 10 steps will help you get your 

plants in the ground properly:

1. Protect seedlings from sunlight, wind, and high temperatures. Carrying plants inside a white 5-gallon bucket 

with their roots wrapped in moist cloth is a good way to 

handle plants on the outplanting site.

2. On forested lands, plant on the north or east sides of 

stumps and logs if possible. Forest floor litter should be

scraped (scalped) away to expose mineral soil, but replaced 

around the seedling after planting. At any planting site, 

scalp dense weedy vegetation. Scalps should be at least 30 

inches square and expose mineral soil (Figure 5.4A)

3. Dig a hole large enough for the root plug. We don’t 

recommend dibbles except for wetland plants. Spades, 

shovels, and hoedads work well for upland plants. Placing the plug into a slit made by rocking a spade or shovel 

is not recommended because rocking may compact the 

soil and hamper root growth.

4. Keep foreign matter (leaves, sticks, duff, rocks, snow, 

and so on) out of the planting hole.

5. If you add fertilizer to the outplanting hole, place it 

deeper than, or to the side of, the root plug so the roots 

are not in immediate contact. Allow roots to grow to the 

fertilizer. Adding fertilizer to a dibble hole next to the 

plant avoids this problem and reduces the chance that 

weeds will intercept the fertilizer.

6. After the hole is ready, remove only one seedling from 

the storage container. This prevents unnecessary exposure 

of the roots of remaining plants. If roots appear dry, dip 

them in a bucket of cool water for a couple of seconds to 

remoisten them.

7. Place your plant near the center of the hole, with the 

top of the root plug about 0.5 to 1 inch below the soil 

line. Planting too deep is better than too shallow as long 

as you don’t bury any foliage.

8. As you fill the hole, gently firm the soil around the

roots. Leave no air spaces. Be sure to use moist soil to fill

the hole, but don’t use heavy pressure that will compact 

the soil.

9. Watering plants, if practical, immediately after outplanting is probably the single best thing you can do because it not only provides moisture but gently settles soil 

particles around the roots (Figure 5.4B).

10. Surround the plant with a protective fabric or organic 

mulch to reflect sunlight, retard moisture loss, and discourage weed growth (Figure 5.4C). On exposed sites, 

shade cards held upright with stakes can greatly reduce 

sunscald and moisture loss. Broad shingles or commercially available plastic cards should be placed on the 

south and southwest sides of outplanted seedlings.

Chapter 5—Outplanting
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 63

the longer the better (Figure 5.4A). Weed-free zones can be 

accomplished with hand weeding, herbicides, or fabric 

weed barriers. Maintaining shade and mulches (Figure 

5.4C) may also increase seedling survival and growth. Using a pre-emergent herbicide immediately after outplanting 

can control weeds, especially annual weeds. Because preemergent herbicides can often be sprayed over the top of 

desired species, the application is much easier to perform; 

using herbicides on established weeds is more difficult 

because desired plants must be shielded from the spray. 

Before you use any herbicides, contact your local state 

forester, university county extension agent, or Natural 

Resources Conservation Service (NRCS) representative 

for information on the products currently available for 

your species. Always follow label directions to protect 

yourself, others, and the environment.

5.4.4 Animal Damage

Many critters eat native plants. Mice, moles, gophers, 

deer, elk, rabbits, and porcupines are just a few of the animals that can be troublesome. Solid plastic tubes or plastic 

mesh cylinders (Figure 5.4D) are products specifically made 

Figure 5.4—Scalping around the planting hole 

removes competing vegetation and conserves soil 

moisture (A). If at all possible, water your plants 

to not only recharge soil moisture but settle soil 

around the root system (B). Mulches provide many 

benefits including reducing evaporation from the 

soil surface, reflecting heat, and retarding weed 

growth (C). Tree shelters are expensive but are 

the best way to protect seedlings from animal 

damage (D).

to reduce browse damage. If you plan to mow weeds around 

your plants, these tubes also protect against accidental 

damage, or “mower blight.” Populations of small rodents 

can also be reduced by natural predators like hawks and 

owls. Placing some wooden fence posts or larger “snags” 

around the outplanting site offers predatory birds a place to 

sit and hunt. Remember that populations of small rodents 

are cyclic, so not observing a problem one year does not 

guarantee the same result in subsequent years. Rodenticides are also available, but great care should be taken 

not to accidentally poison non-target species like dogs, 

cats, hawks, and owls. Fencing works well for deer and 

elk but can be extremely expensive. A variety of spray-on 

repellents are available—they generally reduce, but don’t 

eliminate, browsing. For best results, they should be reapplied frequently to cover new foliage.

5.5 Additional Reading

Landis, T.D.; Dumroese, R.K.; Haase, D.L. 2010. The container tree 

nursery manual. Volume 7, Seedling processing, storage, and outplanting. Agric. Handb. 674. Washington, DC: U.S. Department of 

Agriculture, Forest Service. 200 p.

A

C D

B

Chapter 5—Outplanting
64 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Appendix 6.1 Seed Characteristics of 

Some Common U.S. Plants

This appendix provides seed characteristics and treatments 

important for growing some common native plants of the United 

States. Information is provided by life form (conifer trees, deciduous trees, woody shrubs, forbs [wildflowers], grasses, and 

grass-like plants) and by very general distribution within the 

United States (eastern and western). Please consult local field 

guides to understand which plants are native to your area.

Refer to explanations in sections 2.6 (Seed Storage), 

2.7 (Seed Dormancy), and 2.8 (Seed Treatments) when 

using this appendix.

Appendix 6.1.1—Conifer Trees 

Scientific name Common name Average seeds per pound Seed treatment(s)

Eastern

Abies balsamea Balsam fir 11,000 28 days stratification

Larix laricina Tamarack 250,000 60 days stratification

Picea rubens Red spruce 139,000 None required

Pinus banksiana Jack pine 131,000 0 to 7 days stratification

echinata Shortleaf pine 46,000 60 days stratification

palustris Longleaf pine 4,900 0 to 30 days stratification

resinosa Red pine 52,000 0 to 30 days stratification

rigida Pitch pine 62,000 None required

strobus Eastern white pine 26,000 60 days stratification

taeda Loblolly pine 18,200 30 to 60 days stratification

virginiana Virginia pine 55,000 30 days stratification

Taxodium distichum Bald cypress 5,000 30 days stratification

Taxus canadensis Canada yew 21,000 270 days of stratification

Thuja occidentalis Arborvitae 346,000 30 to 60 days stratification

Sources:

Bonner, F.T.; Karrfalt, R.P. 2008. The woody plant seed manual. Agric. 

Handb. 727. Washington, DC: U.S. Department of Agriculture, 

Forest Service. 1223 p.

Cullina, W. 2000. The New England Wild Flower Society guide to 

growing and propragating wildflowers of the United States and 

Canada. Boston/New York: Houghton Mifflin Co. 322 p.

Lady Bird Johnson Wildflower Center. URL: http://www.wildflower.

org/plants/ (accessed Jan 2012).

Native Plant Network. URL: http://www.nativeplantnetwork.org (accessed Jun 2011).

Schopmeyer, C.S. 1974. Seeds of woody plants in the United States. 

Agric. Handb. 450. Washington, DC: U.S. Department of Agriculture, Forest Service. 883 p.

U.S. Department of Agriculture, Natural Resources Conservation 

Service, Plant List of Accepted Taxonomy and Symbols (PLANTS) 

database. URL: http://plants.usda.gov (accessed Dec 2011).

(continued)

Appendix 6.1 Seed Characteristics of Some Common U.S. Plants
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 65

Western

Abies amabilis Pacific silver fir 12,000 28 days stratification

concolor Concolor fir 11,000 28 to 60 days stratification

grandis Grand fir 19,000 21 to 42 days stratification

lasiocarpa Subalpine fir 34,000 28 to 42 days stratification

magnifica California red fir 7,000 28 to 42 days stratification

procera Noble fir 13,500 21 to 42 days stratification

Chamaecyparis lawsoniana Port Orfordcedar 210,000 0 to 14 days stratification

nootkatensis Alaska yellowcedar 108,000 30 to 90 days stratification

Juniperus californica California juniper 30 to 120 days stratification

communis Common juniper 36,000 45 to 90 days moist, warm treatment 

then 90 to 120 days stratification

occidentalis Western juniper 12,000 45 to 90 days moist, warm treatment 

then 90 to 120 days stratification

osteosperma Utah juniper 5,000 45 to 90 days moist, warm treatment 

then 90 to 120 days stratification

scopularum Rocky Mountain juniper 27,000 45 to 90 days moist, warm treatment 

then 90 to 120 days stratification

Larix lyallii Subalpine larch 142,000 28 days stratification

occidentalis Western larch (tamarack) 137,000 28 days stratification

Libocedrus decurrens Incense-cedar 15,000 28 to 60 days stratification

Picea breweriana Brewer spruce 61,000 0 to 28 days stratification

engelmannii Engelmann spruce 135,000 0 to 28 days stratification

pungens Blue (Colorado) spruce 106,000 0 to 28 days stratification

sitchensis Sitka spruce 210,000 None required

Pinus albicaulis Whitebark pine 2,600 Tumble or sandpaper scarification, 

then 120 to 180 days stratification

aristata Bristlecone pine 18,000 0 to 28 days stratification

attenuata Knobcone pine 25,000 60 days stratification

balfouriana Foxtail pine 17,000 90 to 120 days stratification

contorta var. contorta Shore pine (coastal) 135,000 0 to 28 days stratification

contorta var. latifolia Lodgepole pine (interior) 94,000 0 to 28 days stratification

edulis Pinyon pine 1,900 0 to 60 days stratification

flexilis Limber pine 4,900 21 to 90 days stratification

jeffreyi Jeffrey pine 3,700 0 to 60 days stratification

lambertiana Sugar pine 2,100 60 to 120 days stratification

monophylla Singleleaf pinyon 1,110 28 to 90 days stratification

monticola Western white pine 27,000 30 to 150 days stratification (14 days 

of warm, moist treatment prior to 

stratification may help)

ponderosa Ponderosa pine 12,000 30 to 60 days stratification

Pseudotsuga menziesii 

var. glauca Rocky Mountain Douglas-fir 44,000 21 to 42 days stratification

menziesii var. menziesii Coastal Douglas-fir 39,000 14 to 21 days stratification

Taxus brevifolia Pacific yew 15,000 90 to 200 days moist, warm treatment, 

then 60 to 120 days stratification

Thuja plicata Western redcedar 414,000 0 to 21 days stratification

Tsuga heterophylla Western hemlock 280,000 21 to 90 days stratification

mertensiana Mountain hemlock 114,000 90 days stratification

Appendix 6.1.1—(Continued) 

Scientific name Common name Average seeds per pound Seed treatment(s)

Appendix 6.1 Seed Characteristics of Some Common U.S. Plants
66 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Appendix 6.1.2—Deciduous Trees 

Scientific name Common name Average seeds per pound Seed treatment(s)

Eastern

Acer saccharinum Silver maple 1,780 42 to 90 days stratification

saccharum Sugar maple 7,000 120 days stratification

Aesculus glabra Ohio buckeye 58 60+ days stratification

Betula nigra River birch 375,000 90 to 150 days stratification; sow seeds

on the soil surface and kept moist 

during germination

Carya ovata Shagbark hickory 100 60 days stratification

Cercis canadensis Eastern redbud 18,000 Scarification, then 120 days stratification

Cornus florida Dogwood 4,500 90 days stratification

Fagus grandifolia Amrican beech 1,600 210 days stratification

Fraxinus pennsylvanica White ash 19,000 60 days warm, moist treatment then 60 

to 210 days stratification

Gleditsia triacanthos Honey locust 2,800 Scarification

Gymnocladus dioicus Kentucky coffee tree 230 Scarification, then 60 to 90 days 

stratification

Liriodendron tulipifera Tuliptree 12,250 30 days stratification

Maclura pomifera Osage orange 14,000 30 to 120 days stratification

Morus rubra Red mulberry 360,000 30 to 120 days stratification

Nyssa sylvatica Blackgum 2,500 30 to 120 days stratification

Platanus occidentalis American sycamore 160,000 None required

Populus deltoides Eastern cottonwood 350,000 None required; seeds need light to 

germinate so sow on soil surface 

and keep them moist during 

germination

Prunus serotina Black cherry 2,400 120 to 180 days stratification (14 

days warm, moist treatment before 

stratification may help)

Quercus alba White oak 215 None required

bicolor Swamp white oak 120 None required

rubra Red oak 105 30 to 60 days stratification

velutina Black oak 245 30 to 60 days stratification

Robinia pseudoacacia Black locust 24,000 Scarification

Sassafras albidum Sassafras 5,500 120 days stratification

Tilia americana American basswood 3,000 Scarification, then 120 to 150 days 

stratification

Ulmus americana American elm 70,000 None required; sow seeds on the soil 

surface and keep them moist during 

germination

(continued)

Appendix 6.1 Seed Characteristics of Some Common U.S. Plants
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 67

Acer glabrum Rocky Mountain maple 13,430 90 to 180 days warm, moist treatment 

then 120 to 180 days stratification

grandidentatum Bigtooth maple 6,350 120 days stratification

macrophyllum Bigleaf maple 3,250 40 to 60 days stratification

Alnus incana Thinleaf alder 675,000 60 to 90 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

rubra Red alder 776,000 0 to 30 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

viridis Sitka alder 998,000 60 to 90 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Arbutus menziesii Pacific madrone 258,500 42 to120 days stratification

Betula papyrifera Paper birch 1,380,000 60 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Chilopsis linearis Desert willow 86,000 0 to 60 days stratification

Cercis orbiculata California redbud 27,460 Scarification then 0 to 120 days 

stratification

Cornus nuttallii Pacific dogwood 4,700 Scarification then 90 days stratification

Corylus cornuta var. californica California hazelnut 486 60 to 120 days stratification

Frangula purshiana Cascara 12,000 Scarification then 30 to 140 days 

stratification

Fraxinus latifolia Oregon ash 12,000 30 to 90 days warm, moist treatment 

then 90 days stratification

velutina Velvet leaf ash 20,600 30 to 90 days stratification

Populus balsamifera Black cottonwood None required; seeds need light to 

germinate so sow on soil surface 

and keep them moist during 

germination

fremontii Fremont cottonwood None required; seeds need light to 

germinate so sow on soil surface 

and keep them moist during 

germination

tremuloides Quaking aspen 3,600,000 None required; seeds need light to 

germinate so sow on soil surface 

and keep them moist during 

germination

Prosopis juliflora Mesquite 12,500 Scarification

Quercus gambelii Gambel oak 325 60 to 90 days stratification

garryana Oregon white oak 85 None required

kelloggii California black oak 95 30 to 45 days stratification

Robinia neomexicana New Mexico locust 21,600 Scarification

Salix species Willow Millions None required; seeds need light to 

germinate so sow on soil surface 

and keep them moist during 

germination

Sorbus scopulina Cascade Mountain ash 138,000 120 to 180 days stratification

Appendix 6.1.2—(Continued)

Scientific name Common name Average seeds per pound Seed treatment(s)

Western

Appendix 6.1 Seed Characteristics of Some Common U.S. Plants
68 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Appendix 6.1.3—Woody Shrubs 

Scientific name Common name Average seeds per pound Seed treatment(s)

Eastern

Amelanchier laevis Serviceberry 80,000 30 to 60 days stratification

Asimina triloba Pawpaw 700 60 days stratification

Callicarpa americana Beautyberry 272,000 60 days stratification

Calycanthus floridus Eastern sweetshrub 85,000 30 days stratification

Cornus obliqua Silky dogwood 12,000 100 to 120 days stratification

sericea Redoiser dogwood 18,500 90 days stratification (scarification 

before stratification may help)

Corylus americana American hazelnut 490 60 to 180 days stratification

Euonymus americanus Bursting-heart 35,000 140 days stratification

Gaultheria hispidula Creeping snowberry 3,000,000 83 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

procumbens Eastern teaberry 3,000,000 None required; seeds need light to 

germinate so sow on soil surface 

and keep them moist dur ing 

germination

Hamamelis virginiana American witchhazel 9,000 120 days stratification

Juniperus communis Common juniper 36,000 30 to 180 days stratification

Lindera benzoin Northern spicebush 4,500 90 days stratification

Prunus americana American plum 870 90 to 120 days stratification (may need 

to remove pit)

virginiana Chokecherry 4,800 90 to 120 days stratification

Symphoricarpos albus Common snowberry 140,000 60 to 90 days warm, moist treatment 

then 90 to 120 days stratification

Vaccinium angustifolium Lowbush blueberry 2,000,000 0 to 60 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

corymbosum Highbush blueberry 1,000,000 0 to 60 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

(continued)

Appendix 6.1 Seed Characteristics of Some Common U.S. Plants
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 69

Appendix 6.1.3—(Continued) 

Scientific name Common name Average seeds per pound Seed treatment(s)

Western

Amelanchier alnifolia Serviceberry 82,000 120 to 150 days stratification

Arctostaphylos patula Manzanita Scarification (may need 90 days of 

warm, moist treatment before 

germination occurs)

uva-ursi Bearberry 58,000 Scarification, then 60 to 90 days warm, 

moist treatment then 90 to 120 days 

stratification

Artemisia cana Silver sagebrush 1,300,000 60 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

tridentata Big sagebrush 2,140,000 30 to 90 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Atriplex canescens Fourwing saltbush 23,000 After-ripen in dry storage for 90 days 

then 60 days stratification

Ceanothus velutinus Snowbrush ceanothus 94,000 Scarification, then 90 days stratification

Cercocarpus ledifolius Curlleaf mountain mahogany 48,200 14 to 120 days stratification

Cornus sericea Redoiser dogwood 18,500 90 days stratification (scarification 

before stratification may help)

Crataegus douglasii Black hawthorn 22,600 90 to 120 90 days stratification 

(scarification before stratification 

may help)

Ephedra species Mormon tea 19,000 60 to 90 days stratification

Ericameria nauseosa Rubber rabbitbrush 600,000 60 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Holodiscus discolor Oceanspray 5,000,000 120 days stratification

Mahonia repens Creeping Oregon-grape 51,000 90 to 120 days warm, moist treatment 

then 90 to 120 days stratification

Philadelphus lewisii Lewis’ mockorange 5,300,000 21 to 75 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Physocarpus malvaceus Western ninebark 748,800 90 to 120 days stratification; seeds 

need light to germinate so sow on 

soil surface and keep them moist 

during germination

Prunus americana American plum 870 90 to 120 days stratification (may need 

to remove pit)

virginiana Chokecherry 4,800 90 to 120 days stratification

Purshia mexicana Mexican cliffrose 75,000 60 to 90 days stratification

tridentata Antelope bitterbrush 15,400 60 to 90 days stratification

Rhus trilobata Skunkbush sumac 20,300 Scarification, then 90 days stratification

Rosa woodsii Woods’ rose 50,000 60 to 90 days warm, moist treatment 

then 90 days stratification

Sambucus nigra var. cerulea Blue elderberry 234,000 90 to 120 days stratification

Shepherdia argentea Silver buffaloberry 40,000 60 to 90 days stratification

Symphoricarpos albus Common snowberry 140,000 60 to 90 days warm, moist treatment 

then 90 to 120 days stratification

Vaccinium species Huckleberry 1,500,000 0 to 60 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Appendix 6.1 Seed Characteristics of Some Common U.S. Plants
70 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Appendix 6.1.4—Forbs (Wildflowers )

Scientific name Common name Average seeds per pound Seed treatment(s)

Eastern

Aquilegia canadensis Eastern columbine 504,000 90 days stratification

Asclepias syriaca Common milkweed 48,000 90 days stratification; sow seeds on the 

soil surface and keep them moist 

during germination

tuberosa Butterfly milkweed 70,000 90 days stratification; sow seeds on the 

soil surface and keep them moist 

during germination

Aster novae-angliae New England Aster 1,200,000 60 days stratification

Baptisia australis Blue false indigo 26,000 Scarification (seeds may benefit from 

stratification after scarification)

Bidens cernua Nodding bur marigold 130,000 84 days stratification

Coreopsis lanceolata Lance leaved coreopsis 220,000 90 days stratification

Dalea purpurea Purple prairie clover 290,000 Scarification

Echinacea purpurea Eastern purple coneflower 115,000 90 to 120 days stratification

Eupatorium fistulosum Joe-pye weed 2,000,000 90 days stratification

Gaillardia pulchella Firewheel 238,000 None required

Heliopsis helianthoides Smooth oxeye 105,000 None required

Liatris spicata Blazing star 100,000 None required but 90 days stratification 

may help

Lobelia cardinalis Cardinal flower 1,000,000 None required; seeds need light to 

germinate so sow on soil surface 

and keep them moist during 

germination

Monarda fistulosa Wild bergamot 1,250,000 90 days stratification

Oenothera speciosa Showy evening primrose 3,000,000 None required

Penstemon digitalis Smooth beardtounge 1,800,000 90 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Ratibida pinnata Grey headed coneflower 1,000,000 30 days stratification

Rudbeckia triloba Browneyed Susan 500,000 None required

Senna marilandica Maryland senna 20,500 Scarification then 90 days stratification

Solidago nemoralis Gray goldenrod 1,000,000 90 days stratification

Tephrosia virginiana Goats rue 32,000 14 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Verbena hastata Blue vervain 1,600,000 None required; seeds need light to 

germinate so sow on soil surface 

and keep them moist during 

germination

Vernonia gigantea Giant ironweed 300,000 90 to 140 days stratification

Veronicastrum virginicum Culver’s root 7,750,000 21 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination; seeds do not tolerate 

any drying

(continued)

Appendix 6.1 Seed Characteristics of Some Common U.S. Plants
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 71

Western

Achillea millefolium Yarrow 2,770,000 0 to 14 days stratification

Aquilegia species Columbine 432,000 60 to 90 days stratification

Asclepias speciosa Showy milkweed 245,000 30 to 60 days stratification; sow seeds

on the soil surface and keep them 

moist during germination

Aster laevis Smooth blue aster 1,100,000 0 to 30 days stratification

Balsamorhiza sagittata Arrowleaf balsamroot 55,000 90 to 120 days stratification

Dodecatheon species Shootingstar 1,200,000 60 to 90 days stratification

Castilleja linariifolia Wyoming Indian paintbrush 4,915,000 60 to 90 days stratification

miniata Giant red Indian paintbrush 4,900,000 60 to 90 days stratification

Echinacea angustifolia Blacksamson echinacea 128,000 30 to 90 days stratification

Eriogonum umbelllatum Sulfur buckwheat 209,000 60 to 90 days stratification

Gaillardia aristata Indian blanketflower 132,000 0 to 30 days stratification

Heuchera cylindrica Alumroot 6,363,000 30 to 60 days stratification

Iliamna rivularis Mountain hollyhock 45,450 Scarification then 60 days stratification

Liatris punctata Dotted blazing star 139,000 30 days stratification

Lupinus sericeus Silky lupine 12,900 Scarification then 30 to 60 days 

stratification

Monarda fistulosa Wild bergamot 1,498,000 30 to 60 days stratification

Oenothera pallida White evening primrose 2,500,000 30 to 60 days stratification

Oxytropis species Locoweed 594,000 Scarification then 0 to 60 days 

stratification

Penstemon eatonii Firecracker penstemon 600,000 60 days stratification

nitidus Shining penstemon 550,000 60 to 90 days stratification

strictus Rocky Mountain penstemon 592,000 60 to 90 days stratification

Ratibida columnifera Prairie coneflower 1,230,000 0 to 30 days stratification

Rudbeckia hirta Blackeyed Susan 1,710,000 0 to 30 days stratification

Sphaeralcea coccinea Scarlet globe mallow 500,000 Scarification then 0 to 30 days 

stratification

Wyethia amplexicaulis Mule ears 24,625 0 to 60 days stratification

Appendix 6.1.4—(Continued)

Scientific name Common name Average seeds per pound Seed treatment(s)

Appendix 6.1 Seed Characteristics of Some Common U.S. Plants
72 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Appendix 6.1.5—Grasses and Grass-Like Plants 

Scientific name Common name Average seeds per pound Seed treatment(s)

Eastern

Agrostis perennans Upland bentgrass 8,000,000 None required

Andropogon gerardii Big bluestem 144,000 90 days stratification

Bouteloua curtipendula Sideoats gamma 710,000 None required

Calamagrostis canadensis Bluejoint 3,300,000 None required

Carex scoparia Blunt broom sedge 1,300,000 60 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Chasmanthium latifolium Indian woodoats 90,000 None required

Danthonia spicata Poverty oatgrass 448,000 None required (tumble scarification may 

help)

Elymus canadensis Canada wildrye 114,000 None required but 14 days stratification 

improves germination

virginicus Virginia wild rye 100,000 None required

Juncus effusus Common rush 4,500,000 0 to 270 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Leersia oryzoides Rice cutgrass 5,000,000 None required

Panicum virgatum Switchgrass 259,000 14 days stratification

Schizachyrium scoparium Little bluestem 240,000 30 to 60 days stratification

Scirpus cyperinus Wool bulrush 9,000,000 30 to 120 days stratification; sow seeds

on the soil surface and keep them 

moist during germination

Sorghastrum nutans Indian grass 175,000 Dry, cool storage for 90 days; or, 90 

days cold stratification 

Sporobolus compositus Tall dropseed 750,000 None required

Tridens flavus Purpletop tridens 14 to 90 days stratification

(continued)

Appendix 6.1 Seed Characteristics of Some Common U.S. Plants
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 73

Appendix 6.1.5—(Continued)

Scientific name Common name Average seeds per pound Seed treatment(s)

Western

Achnatherum hymenoides Indian ricegrass 141,000 Tumble or sandpaper scarification then 

0 to 30 days stratification

Bouteloua curtipendula Sideoats grama 191,000 0 to 30 days stratification

Carex aquatilis Water sedge 485,000 30 to 90 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

microptera Small wing sedge 847,000 60 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

nebrascensis Nebraska sedge 534,100 60 to 90 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

urticulata Beaked sedge 444,000 30 to 60 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Eleocharis palustris Common spikerush 620,000 0 to 90 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Festuca idahoensis Idaho fescue 450,000 0 to 30 days stratification

Hesperostipa comata Needle and thread 115,000 0 to 14 days stratification

Juncus balticus Baltic rush 10,900,000 60 to 90 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

torreyi Torrey rush 12,300,000 30 to 90 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Nassella viridula Green needlegrass 181,000 0 to 30 days stratification

Schoenoplectus acutus Hardstem bulrush 377,600 Tumble or sandpaper scarification then 

30 to 60 days stratification

americanus Chairmaker’s bulrush 179,800 30 to 60 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

tabernaemontani Softstem bulrush 550,000 30 to 60 days stratification; seeds need 

light to germinate so sow on soil 

surface and keep them moist during 

germination

Appendix 6.1 Seed Characteristics of Some Common U.S. Plants
74 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Appendix 6.2. More Intensive 

Fertilization for Bareroot Seedlings: 

An Introduction

The percentage of N, P, and K in a bag of fertilizer is 

always given in the order of N:P:K. Well, that’s not quite 

right. Because of some archaic convention, the percentages 

of P and K are really given as percentages of the oxides of 

P and K: P2O5 and K2O. Therefore, a bag of 8:10:3 has 8% 

N, 10% P2O5, and 3% K2O by weight. To convert P2O5 to 

P, you’ll need to multiply the percentage of P2O5 by 0.437. 

Similarly, to convert K2O to K, multiply K2O by 0.83. This 

process may sound confusing, but let’s work through an 

example using this equation:

Let’s say we want to use some 8:10:3 fertilizer, we want 

to apply 35 pounds of N per acre, and our nursery bed is 

4 feet wide and 45 feet long (180 square feet). 

First, divide 35 pounds of N by the percentage of N in 

the fertilizer (0.08):

35 ÷ 0.08 = 438 pounds of fertilizer per 

acre to get 35 pounds of N per acre. 

Divide the 438 pounds of fertilizer by 43,560 (the number 

of square feet in an acre):

438 ÷ 43,560 = 0.01 pounds of fertilizer 

per square foot. 

Multiply 0.01 pounds of fertilizer per square foot by the 

180 square feet in the nursery bed:

0.01 x 180 = 1.8 pounds of fertilizer 

should be applied to the nursery bed.

Okay, how much P and K were applied at the same time? 

For P, multiply the 1.8 pounds of fertilizer by 0.1 (remember there’s 10% P2O5 in the fertilizer):

1.8 x 0.1 = 0.18 pounds of P2O5 were 

also applied to the nursery bed.

Convert that to P:

0.18 x 0.437 = 0.08 pounds of P were 

applied to the nursery bed.

You may convert that back to a pounds-per-acre rate by 

dividing it by 180 (that gives you pounds of P per square 

foot) and then multiplying by 43,560:

0.08 ÷ 180 = 0.000044 and 0.000044 

x 43,560 = 19 pounds of P per acre. 

Similarly, to determine how much K was applied, take 

the 1.8 pounds of fertilizer and multiply it by 0.03 (3% K2O 

in the fertilizer); we applied 0.05 pounds of K2O. Convert 

that to K by multiplying 0.05 pounds of K2O by 0.83; 0.04 

pounds of K. Like P, you can convert back to pounds of 

K per acre by dividing by 180 and multiplying by 43,560; 

we applied 9.7 pounds of K per acre.

In commercial bareroot nurseries, commonly used fertilizers are ammonium phosphate (11:55:0), ammonium nitrate 

(33:0:0), ammonium sulfate (21:0:0), calcium superphosphate (0:20:0), triple superphosphate (0:45:0), and potassium 

sulfate (0:0:50). In general, if you have a soil with pH less 

than 6.0, your fertilizers of choice would be ammonium 

phosphate and ammonium nitrate. These fertilizers help 

maintain your pH around 5.0 to 6.0. However, if your soil 

pH is on the high side (over 6.0) use ammonium sulfate. 

One advantage of using single element fertilizers is the 

ease of manipulating the amounts of each nutrient applied; 

only one nutrient is in each fertilizer formulation. Commercial operators have the luxury of using a particular 

fertilizer to apply a particular nutrient. Novice growers 

who wish to use an organic alternative may find that their 

choices for fertilizers usually include multiple nutrients per 

fertilizer formulations (for example, 9:1:1 or 0:3:1). This 

means more arithmetic for organic farmers because they 

may have to do some “tinkering” with their formulations 

and application amounts to achieve recommended fertilizer 

rates. 

Regardless of your situation, right before the first growing 

season, plan on incorporating P and K into your nursery 

beds. If you have a good sandy soil, add some N as well. 

If your soil is too acidic (pH under 5) or too basic (pH 

over 6) for conifer seedlings, this is also the time to add 

lime to bring the pH back up or sulfur to lower pH. Use a 

whirly-bird-type spreader or drop-type spreader to apply 

fertilizer. You may have to mix it with sand to have enough 

material to fill your spreader and ensure an even application. Make sure it’s applied evenly! Spade or rototill the 

fertilizer into the soil. Once your crop is growing, you’ll 

need to topdress N and K over the top of your seedlings. 

If damping-off is a problem, avoid early applications of N 

during the first season.

Appendix 6.2 More Intensive Fertilization for Bareroot Seedlings – An Introduction
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 75

Appendix 6.2.1.—Intensive Bareroot Fertilization for Soil With Ph Less Than 6.0.

 Ounces of

 Number Rate Fertilizer fertilizer per

Year Timing Nutrient of applications (pounds per acre) (see footnote) 100 square feet

First Season Pre-sow N 1 35 11:55:0 A 12

 P 1 120 0:20:0 18

 K 1 45 0:0:62 3

 Top-dress N 4 20 33:0:0 2

 (mid-June, early 

 and mid-July, & 

 late September)

 K 1 20 0:0:62 1.5

 (mid-summer)

Second Season Top-dress N 1 (March) 35 33:0:0 3.5

 K 1 (March) 20 0:0:62 1.5

 N 4 

 (May, June, July, 20 33:0:0 2

 late September)

 K 2 20 0:0:62 1.5

 (early and mid-summer)

Transplants Pre-plant P 1 60 0:20:0 25

 K 1 45 0:0:62 1.5

 Top-dress N 4 40 33:0:0 4

 (May, June, July, 

 late September)

 K 2 20 0:0:62 1.5

 (early and mid-summer)

Fertilizers:

11:55:0 Ammonium phosphate

33:0:0 Ammonium nitrate

0:20:0 Calcium superphosphate

0:0:62 Potassium chloride

A Note the application of 12 oz of 11:55:0 supplies the necessary rate of N (35 lbs per acre) and 78 lbs of the suggested 120 lbs of P per acre. 

Therefore, the amount of 0:20:0 supplies only 42 lbs of P per acre (the difference between 120 and 78).

Adapted from: van den Driessche, R. 1984. Soil fertility in forest nurseries. In: Duryea, M.L.; Landis, T.D., eds. Forest nursery manual: production 

of bareroot seedlings. The Hague; Boston; Lancaster: Martinue Nijhoff/Dr. W. Junk Publishers. For Forest Research Laboratory, Oregon State 

University, Corvallis: 63-74.

Appendix 6.2 More Intensive Fertilization for Bareroot Seedlings – An Introduction
76 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Appendix 6.2.2.—Intensive Bareroot Fertilization for Soil With Ph Greater Than 6.0.

 Ounces of

 Number Rate Fertilizer fertilizer per

Year Timing Nutrient of applications (pounds per acre) (see footnote) 100 square feet

First Season Pre-sow N 1 35 11:55:0 A 12

 P 1 120 0:45:0 8

 K 1 45 0:0:50 4

 Top-dress N 4 20 21:0:0 3.5

 (mid-June, early 

 and mid-July, & 

 late September)

 K 1 (mid-summer) 20 0:0:50 2

Second Season Top-dress N 1 (March) 35 21:0:0 6

 K 1 (March) 20 0:0:50 2

 N 4 20 21:0:0 3.5

 (May, June, July, 

 late September)

 K 2

 (early and mid- 20 0:0:50 2

 summer)

Transplants Pre-plant P 1 60 0:45:0 11

 K 1 45 0:0:50 2

 Top-dress N 4 40 21:0:0 7

 (May, June, July, 

 late September)

 K 2 20 0:0:50 2

 (early and mid-summer)

Fertilizers:

11:55:0 Ammonium phosphate

21:0:0 Ammonium sulfate

0:45:0 Triple superphosphate

0:0:50 Potassium sulfate

A Note the application of 12 oz of 11:55:0 supplies the necessary amount of N (35 lbs per acre) and 78 lbs of the suggested 120 lbs of P per 

acre. Therefore, the amount of 0:45:0 supplies only 42 lbs of P per acre (the difference between 120 and 78).

Adapted from: van den Driessche, R. 1984. Soil fertility in forest nurseries. In: Duryea, M.L.; Landis, T.D., eds. Forest nursery manual: production 

of bareroot seedlings. The Hague; Boston; Lancaster: Martinue Nijhoff/Dr. W. Junk Publishers. For Forest Research Laboratory, Oregon State 

University, Corvallis: 63-74.

Appendix 6.2 More Intensive Fertilization for Bareroot Seedlings – An Introduction
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 77

Appendix 6.2.3.—Organic Fertilization of Bareroot Seedlings

 Ounces of

 Number Rate Fertilizer fertilizer per

Year Timing Nutrient of applications (pounds per acre) (see footnote) 100 square feet

First Season Pre-sow N 1 35 9:1:1 A 14

 P 1 120 0:7:0 98

 K 1 45 0:3:1 58

 Top-dress N 4 20 9:1:1 B 8

 (mid-June, early and 

 mid-July, & late September)

 K 1 20 0:0:7 8

 (mid-summer)

Second Season Top-dress N 1 (March) 35 9:1:1 C 14

 K 1 (March) 20

 N 4 

 (May, June, July, 20 9:1:1 8

 late September)

 K 2 20 0:0:7 10

 (early and mid-

 summer)

Transplants Pre-plant P 1 60 0:3:1 D 168

 K 1 45 0:0:7 4

 Top-dress N 4 40 9:1:1 E 16

 (May, June, July,

 late September)

 K 2 20 0:0:7 8

 (early and mid-summer)

Fertilizers:

9:1:1 Ocean Fresh Fish Powder

0:7:0 Budswel

0:3:1 Earth Juice Bloom

0:0:7 Greensand

A Applying 14 oz of 9:1:1 supplies 34 lbs of N, 16 lbs of P, and 32 lbs of K per acre. Applying 58 oz of 0:3:1 supplies the remaining 13 lbs of K 

(45 lbs total) and 21 more lbs of P Since we’ve only applied 37 lbs of P, apply 98 oz of 0:7:0 to supply the final 82 lbs of P suggested (120 lbs 

total).

B Four applications of 9:1:1 also supply 7.2 lbs of K (1.8 lbs per application). Therefore, we only need 8 oz of 0:0:7 (12.6 lbs of K) to achieve the 

suggested 20 lbs of K.

C Applying 14 oz of 9:1:1 supplies 34 lbs of N and 32 lbs of K per acre, which also satisfies our K requirement. 

D Applying 168 oz of 0:3:1 provides 60 lbs of P and 38 lbs of K, so an additional 4 oz of 0:0:7 supplies 7 lbs of K to bring the total to the recommended rate of 45 lbs.

E Four applications of 9:1:1 also supply 14.4 lbs of K (3.6 lbs per application). Therefore, we only need 2 applications of 8 oz of 0:0:7 (12.6 lbs 

of K each application) to achieve the suggested 40 lbs of K.

Adapted from: van den Driessche, R. 1984. Soil fertility in forest nurseries. In: Duryea, M.L.; Landis, T.D., eds. Forest nursery manual: production of bareroot seedlings. The Hague; Boston; Lancaster: Martinue Nijhoff/Dr. W. Junk Publishers. For Forest Research Laboratory, Oregon 

State University, Corvallis: 63-74.

Appendix 6.2 More Intensive Fertilization for Bareroot Seedlings – An Introduction
78 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Appendix 6.3. Calculating the Number of Seeds to Sow per 

Container Using a Hand-Held Calculator

The technique is based on the concept that a seed either grows or it doesn’t (binomial probability). If “X” equals the 

probability of a seed germinating and “Y” equals the probability of it failing to germinate, a binomial expansion can be 

constructed that includes all possible occurrences. The following example shows the possibilities when 2 seeds are sown 

per container:

(X+ Y)2 = X2 + 2XY +Y2

where: X2 = the probability of both seeds germinating

2XY = the probability of only one germinating

Y2 = the probability of neither seed germinating

So, as long as germination test data are known, the proper number of seeds to sow per container can be easily determined 

by entering the “germination failure” on a hand-held calculator with a universal power key (YX , XY, xy, or something 

similar). The procedure consists of keying in the decimal equivalent of the germination failure, pushing the universal 

power key, entering the number of seeds you might sow, and finally pushing the “equals” key. If your calculator doesn’t 

have a universal power key, then just use repeated multiplication. For example, a seedlot with 78% germination has a 22% 

failure score:

Seeds per Percentage of Empty Containers

container Using YX key Using repeated multiplication

1 (0.22)1 = 0.22 = 22% 0.22 = 22%

2 (0.22)2 = 0.0484 = 4.8% 0.22 x 0.22 = 0.0484 = 4.8%

3 (0.22)3 = 0.0106 = 1.1% 0.22 x 0.22 x 0.22 = 0.0106 = 1.1% 

4 (0.22)4 = 0.0023 = 0.2% 0.22 x 0.22 x 0.22 x 0.22 = 0.0023 = 0.2%

You can see that the calculation becomes a “law of diminishing returns,” and the best number of seeds to sow will 

depend on seed availability, seed cost, cost of thinning, and the reliability of the germination test. In this example, most 

nurseries would be satisfied with sowing 2 to 3 seeds per container.

Source: Schwartz, M. 1993. Germination math: calculating the number of seeds necessary per cavity for a given number 

of live seedlings. Tree Planters’ Notes 44(1):19-20.

Appendix 6.3 Calculating the Number of Seeds to Sow Per Container Using a Hand-held Calculator
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 79

Appendix 6.4 Soluble Fertilizer Chemicals That Provice Macronutrients...

% of Nutrient Supplied

Compound Chemical formula NH4-N NO3-N P K Ca Mg S

Ammonium nitrate NH4NO3 17 17 — — — — —

Ammonium sulfate (NH4)2SO4 21 — — — — — 24

Calcium nitrate Ca(NO3)2 — 15 — — 17 — —

Diammonium phosphate (NH4)2HPO4 21 — 24 — — — —

Dipotassium phosphate K2HPO4 — — 18 45 — — —

Magnesium sulfate MgSO4 — — — — — 10 13

Monoammonium phosphate NH4H2PO4 11 — 21 — 1 — 3

Monopotassium phosphate KH2PO4 — — 23 28 — — —

Nitric acid HNO3 — 22 — — — — —

Phosphoric acid H3PO4 — — 32 — — — —

Potassium carbonate K2CO3 — — — 56 — — —

Potassium chloride KCI — — — 52 — — —

Potassium nitrate KNO3 — 13 — 37 — — —

Potassium sulfate K2SO4 — — — 44 — — 18

Sodium nitrate NaNO3 — 16 — — — — —

Sulfuric acid H2SO4 — — — — — — 33

Urea CO(NH2)2 45 — — — — — —

Adapted from: Table 4.1.23—Soluble fertilizer chemicals that provide macronutrients for custom fertilizer solutions. Found in: 

Landis, T.D.; Tinus, R.W.; McDonald, S.E.; Barnett, J.P. 1989. The container tree nursery manual. Volume 4, Seedling nutrition 

and irrigation.. Agric. Handb. 674. Washington, DC: U.S. Department of Agriculture, Forest Service. 119 p.

Appendix 6.4. Soluble Fertilizer Chemicals that Provide Macronutrients 

for Custom Fertilizer Solutions for Container Seedlings
80 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 81

Appendix 6.5. Calculating Parts Per 

Million and More Intensive Fertilization 

for Container Seedlings

If you use any other fertilizers than the ones listing in 

Table 3.8, you’ll need to determine how much fertilizer to 

mix in a volume of water to get the suggested ppm. Before 

we calculate ppm, let’s first review fertilizer in general. As 

discussed for bareroot seedlings, the percentage of N, P, 

and K in a bag of fertilizer is always given in the order of 

N:P:K. And as was the case for bareroot seedlings, that’s 

not quite right. The percentages of P and K are really given 

as the percentages of the oxides of P and K: P2O5 and K2O. 

Therefore, a bag of 30:10:10 has 30% N, 10% P2O5, and 

10% K2O by weight. To convert P2O5 to P, you’ll need to 

multiply the percentage of P2O5 by 0.437. Similarly, to 

convert K2O to K, multiply K2O by 0.83.

Fortunately, for fertilization of container seedlings more 

interest is on the rate of N. Many professional growers 

fertilize their crops with rates expressed in “some weight 

of fertilizer mixed in some volume of water” (ounces per 

100 gallons, or pounds per 1,000 gallons). Some growers 

use some weight of N per volume of water. Finally, some 

growers fertilize using parts per million (ppm) or even 

milligrams of a nutrient per volume of water, both of which 

are just a more refined version of “some weight of fertilizer 

mixed in some volume of water.”

Calculating ppm’s isn’t really that difficult. A good 

rule of thumb is that one ounce of granular fertilizer in 

100 gallons of water equals about 75 ppm of fertilizer. If 

your fertilizer is 30% N, then the ppm N in that solution 

is 75 x 0.3 = 22.5 ppm N. 

If you wanted 135 ppm N, you would have to divide 135 

ppm N by the percentage of N in the fertilizer (30%) and 

divide that by 75:

135 ppm ÷ 0.3 ÷ 75 = 6 ounces of 

fertilizer in 100 gallons.

If your fertilizer is 10% P2O5, then the ppm P2O5 when 

you mix 1 ounce of fertilizer in 100 gallons of water is 75 

x 0.1 = 7.5 ppm P2O5. Remember to multiply 7.5 by 0.437 

to convert P2O5 to P (7.5 x 0.437 = 3 ppm P) and multiply 

7.5 by 0.83 to convert K2O to K (7.5 x 0.83 = 6 ppm K).

Some professional growers strictly use premixed 

fertilizers (like Peters Conifer Grower®), some use a 

combination of premixed and custom-mixed fertilizers, 

and some only used custom-mixed. The discrepancy usually 

depends on the background of the grower. Growers using 

custom-mixed fertilizer feel they have better control over the 

growth of their seedlings, and can manipulate fertilizers to 

achieve particular growth responses in the crop. Customized 

fertilizers blend the “science” of growing seedlings with 

the “art” of growing seedlings, and usually experience is 

key. Most growers like to add calcium to their fertilizers 

(not found in Miracid or Miracle-Gro) to promote stem 

diameter development in their seedlings. Some growers 

like to reduce the rate of N while maintaining high levels 

of K to promote bud initiation and hardening; raising K 

levels can be easily done with a custom-mixed fertilizer. 

Commonly used fertilizers for growing container seedlings 

can be found in Appendix 6.4.

As mentioned earlier, the actual rates necessary vary 

from locale to locale, and the following example in 

Appendix 6.5.1 shows the tremendous variability found 

among four nurseries in the northern Rocky Mountains 

in regard to how they fertilize a crop of ponderosa pine 

seedlings. Amazingly, all four nurseries grow excellent 

seedlings that thrive once outplanted. So go ahead, experiment! Keep detailed notes so you can develop your own 

“art” in seedling production.

Appendix 6.5 Calculating Parts Per Million and More Intensive Fertilization for Container Seedlings
82 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

Appendix 6.5 Calculating Parts Per Million and More Intensive Fertilization for Container Seedlings

Nursery #1

Weeks 2 to 4

3.5 fluid oz CAN-17

4 oz KH2PO4

1 oz K2SO4

Week 5

3 fluid oz CAN-17

1 oz NH4NO3

2 oz KNO3

3.5 oz CaCl2

1.5 oz KH2PO4

1 oz K2SO4

Week 6

3.5 fluid oz CAN-17

2 oz NH4NO3

2 oz KNO3

3.5 oz CaCl2

1.5 oz KH2PO4

1 oz K2SO4

Weeks 7 to 9

5.5 fluid oz CAN-17

2 oz NH4NO3

2 oz KNO3

2 oz CaCl2

1.5 oz KH2PO4

1 oz K2SO4

Weeks 10 to 12

6.5 fluid oz CAN-17

3 oz NH4NO3

2 oz KNO3

1 oz CaCl2

1.5 oz K3PO44

1 oz K2SO4

Nursery #2

Weeks 2 to 6

8 oz Peters Conifer Starter (7:40:17)

Weeks 7 to 10

8 oz Peters Conifer Grower (20:17:19) 

alternated with 4 fluid oz CAN-17

Weeks 11 to 12

4 fluid oz CAN-17

Nursery #3

Week 2

8 oz 10:52:10

Weeks 3 to 13

8 oz Ca(NO3)2 alternated with 16 oz KNO3

Nursery #4

Week 2

8 oz 5:15:35 

Week 3

2.5 oz Ca(NO3)2

1.5 oz KNO3

Week 4

5 oz Ca(NO3)2

3 oz KNO3

Weeks 5 to 12

12 oz Ca(NO3)2

4 oz KNO3 alternated with 16 oz 

Ca(NO3)2

Appendix 6.5.1. Fertilization of a Container Crop of Ponderosa Pine

Ratios of N:P:K:Ca (ppm) applied to ponderosa pine crops up to the time of bud initiation at four nurseries in the northern Rocky Mountains. Stock 

solution recipes for these ppm rates are provided below as amounts of fertilizer per 100 gallons of water. See Appendix 6.4 for fertilizer abbreviations. 

Nursery

Weeks after sowing

2 3 4 5 6 7 to 9 10 11 to 12 13

1 70:120:110:140 110:80:120:140 140:80:120:140 185:80:105:120 230:80:120:120

2 42:176:83:0

60:82:47:0 alternated with 

81:0:0:42 81:0:0:42

3 59:134:49:0 92:0:0:101 alternated with 163:0:452:0

4 30:69:172:0 44:30:51:31 88:30:102:62 179:30:136:149 alternated with 186:30:0:198
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012 83

Appendix 6.5 Calculating Parts Per Million and More Intensive Fertilization for Container Seedlings

Nursery #1

Weeks 13 to 16

1 fluid oz CAN-17

6.5 oz CaCl2

2.5 oz KH2PO4

2 oz K2SO4

Weeks 17 to extraction

3 fluid oz CAN-17

1 oz KNO3

5.5 oz CaCl2

2.5 oz KH2PO4

1.5 oz K2SO4

Nursery #2

Weeks 13 to 16

4 fluid oz CAN-17

Weeks 17 to extraction

8 oz Peters Conifer Finisher 

(4:25:35) alternated with 8 fluid oz 

CAN-17

Nursery #3

Week 14 to extraction

6 oz Ca(NO3)2 alternated with 6 oz 

KNO3

Nursery #4

Weeks 13 to 14

4 oz CaCl2

2.4 oz KCl alternated with 8 oz 

K3PO4 alternated with 8 oz KCl

Weeks 15 to 16

2.5 oz Ca(NO3)2

1.5 oz KNO3

Weeks 17 to 19

5 oz Ca(NO3)2

3 oz KNO3

Weeks 20 to 22

8 oz Ca(NO3)2

4 oz KNO3

Weeks 23 to extraction

12 oz Ca(NO3)2

4 oz KNO3

alternated with

16 oz Ca(NO3)2

Adapted from: Dumroese, R.K.; Wenny, D.L. 1997. Fertilizer regimes for container-grown conifers of the Intermountain West. In: Haase, D.L.; Rose, R., coords. & 

eds. Symposium proceedings—Forest seedling nutrition from the nursery to the field; October 28-29, 1997; Corvallis, OR. Oregon State University, Nursery 

Technology Cooperative: 17-26.

Nursery

Weeks after sowing

13 14 15 16 17 to 19 20 to 22 23 to extraction (30 to35)

1 20:90:120:190 60:90:120:185

2 81:0:0:42 24:138:173:0 alternated with 162:0:0:84

3 69:0:0:75 alternated 61:0:169:0

4 0:30:94:106 alternated with 

0:165:169:0 alternated with 

0:30:314:0

44:30:51:31 88:30:102:62 133:30:136:99 179:30:136:149 alternated with 

186:30:0:4198
84 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-274. 2012

 Multiply By To Obtain Multiply By To Obtain

Appendix 6.6. Handy Conversions

Appendix 6.6 Handy Conversions

Acres 43,560 square feet

Acres 0.4047 square hectares

Acres 4,047 square meters

Bed feet 0.3716 square meters

Bed foot 4.0 square feet

Bed meter 13.12 square feet

Bushels 1.244 cubic feet

Bushels 0.03524 cubic meters

Centimeters 0.3937 inches

Cubic feet 0.8 bushels

Cubic feet 0.02832 cubic meters

Cubic feet 0.03704 cubic yards

Cubic meters 35.31 cubic feet

Cups 0.5 pints

Cups 0.25 quarts

Cups 16 tablespoons

Cups 48 teaspoons

Feet 30.48 centimeters

Feet 0.3048 meters

Gallons 3.785 liters

Gallons 128 ounces (fluid)

Gallons 8 pints (fluid)

Gallons 4 quart (fluid)

Gallons of water 8.3453 pounds of water

Grams 0.03527 ounces

Grams 0.002205 pounds

Grams per liter 1,000 parts per million

Grams per liter 0.1336 ounces per gallon

Hectares 2.471 acres

Hectares 107,000 square feet

Inches 2.540 centimeters

Inches 0.0254 meters

Kilograms 1,000 grams

Kilograms 35.27 ounces

Kilograms 2.2046 pounds

Liters 0.2642 gallons

Liters 2.113 pints (fluid)

Liters 1.057 quarts (fluid)

Meters 3.2808 feet

Meters 39.37 inches

Ounces 28.35 grams

Ounces 0.0625 pounds

Ounces 3 tablespoons (dry)

Ounces 9 teaspoons (dry)

Ounces (fluid) 0.0078125 gallons

Ounces (fluid) 0.02957 liters

Ounces (fluid) 29.57 milliliters

Ounces (fluid) 2 tablespoons (fluid)

Ounces (fluid) 6 teaspoons (fluid)

Ounces per gallon 7.812 milliliters per liter

Ounces per square foot 2722 pounds per acre

Parts per million 1 milligrams per kilo gram

Parts per million 1 milligrams per liter

Parts per million 0.013 ounces per 100 gallons

Parts per million 0.0083 pounds per 1000 gallons

Pints (fluid) 0.125 gallons

Pints (fluid) 0.4732 liters

Pints (fluid) 16 ounces (fluid)

Pints (fluid) 0.5 quarts (fluid)

Pounds 453.594 grams

Pounds 0.453594 kilograms

Pounds 16 ounces

Pounds of water 0.1198 gallons

Pounds per acre 1.12 kilograms per hectare

Pounds per acre 0.000377 ounces per square foot

Pounds per square foot 4.882 kilograms per square meter

Quarts (fluid) 0.25 gallons

Quarts (fluid) 0.9463 liters

Quarts (fluid) 946.3 milliliters

Quarts (fluid) 32 ounces (fluid)

Quarts (fluid) 2 pints (fluid)

Square feet 0.000023 acres

Square feet 0.0929 square meters

Square feet 0.25 bed feet 

Square feet 0.0762 bed meters

Square meters 0.000247 acres

Square meters 10.764 square feet

Tablespoons (dry) 0.0625 cups (dry)

Tablespoons (dry) 0.333 ounces (dry)

Tablespoons (dry) 3 teaspoons (dry)

Tablespoons (fluid) 0.0625 cups (fluid)

Tablespoons (fluid) 15 milliliters

Tablespoons (fluid) 0.5 ounces (fluid)

Teaspoons (dry) 0.111 ounces (dry)

Teaspoons (dry) 0.333 tablespoons (dry)

Teaspoon (fluid) 0.0208 cups (fluid)

Teaspoon (fluid) 5 milliliters

Teaspoon (fluid) 0.1666 ounces (fluid)

Temperature (oC) +17.8 1.8 temperature oF

Temperature (oF) -32 0.55 temperature oC

Sources:

Bonaminio, V.P. Extension Horticultural Specialist, The North Carolina Agricultural Extension Service. 

Duryea, M.L.; Landis, T.D. eds. Production of bareroot seedlings. The Hague; Boston; Lancaster: Martinue 

Nijhoff/Dr. W. Junk Publishers. For Forest Research Laboratory, Oregon State University, Corvallis. 386 p.

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