Sampling Guidelines for Hemp

U.S. Domestic Hemp Production Program 

Issued January 15, 2021 

Purpose:

1. Standard and Performance-based sampling guidelines are specified for field and indoor

sampling of hemp. States and Tribes shall develop their own sampling protocols in accordance

with §990.3.

2. Samples are taken to obtain specimens for the measurement of total tetrahydrocannabinol

(THC) content, which determine whether the specimens are hemp or marijuana. The

measurements are intended to be representative of the total THC content in a “lot” of hemp crop

acreage as identified by the producer. Hemp producers may not harvest hemp prior to the hemp

being sampled for THC concentration. Testing procedures are provided in a separate guidance

document.

Scope:

1. Samples collected under this procedure are acceptable for submission to a qualified testing

laboratory for determination of total THC concentration in hemp. After December 31, 2024, all

laboratories testing hemp under the U.S. Domestic Hemp Production Program must be registered

with the DEA in accordance with §990.3(a)(3)(iii)(H) and §990.25(g)(iii).

2. Since the THC content of hemp generally peaks as the plant ripens, the timing of when

sampling occurs is important to accurately measure total THC concentration and monitor

compliance with the USDA hemp production program. Harvest shall be completed within 30

days from sample collection.

3. Samples shall be collected only by a trained sampling agent. Sampling agents must be trained

under applicable USDA, State, or Tribal training procedures. States and Tribes must maintain

information, available to producers, about trained sampling agents. Hemp producers may not act

as sampling agents.

4. It is the responsibility of the licensed producer to pay any fees associated with sampling.

5. It is the responsibility of the sampling agent to pay any fees associated with sampling agent

training or testing.

Summary of Practice: 

1. This practice provides procedures for entering a growing area and collecting the minimum

number of plant specimens necessary to represent a homogeneous composition of the “lot” that is

to be sampled. A trained sampling agent enters a growing area, strategically examines the

growing area, establishes an approach for navigating the growing area, and collects individual

specimens of plants in order to obtain a representative sample of hemp in the designated lot.
2. Cuttings from each “lot” of hemp crop acreage, as identified by the producer, and submitted to

and uniquely identified by the Farm Service Agency (FSA) per the requirements of the USDA

hemp production program, shall be organized as composite samples. The terminology used by

FSA to denote land areas include terms like “farm,” “tract,” “field,” and “subfield,” which are

equivalent to AMS’s term “lot.” For the purposes of these procedures, a “lot” is a contiguous

area in a field, greenhouse, or indoor growing structure containing the same variety or strain of

cannabis throughout. In addition, “lot” refers to the batch of contiguous, homogeneous whole of

a product being sold to a single buyer at a single time. The size of the “Lot” is determined by the

producer in terms of farm location and field acreage and is to be reported as such to the FSA.

Performance-Based Sampling Protocols:

1. States and Tribes may develop performance-based sampling protocols.

2. Performance-based sampling protocols may consider seed certification processes, other

process that identify varieties that have consistently resulted in compliant hemp plants, whether

the producer is conducting research on hemp at an institution of higher learning or that is funded

by a Federal, State, or Tribal government, whether a producer has consistently produced

compliant hemp plants over an extended period of time, and other similar factors.

3. Performance-based sampling protocols may consider alternative requirements for operations

that grow “immature” cannabis that does not reach the flowering stage. These facilities may

grow seedlings, clones, microgreens, or other non-flowering cannabis, as determined by the State

or Tribe.

4. A performance-based sampling protocol must have the potential to ensure, at a confidence

level of 95 percent, that the cannabis plants will not test above the acceptable hemp THC level of

0.3 percent on a dry weight basis.

5. Regardless of the specific performance-based sampling requirements developed under a State

or Tribal plan, all samples must be collected from the flowering tops of the plant by cutting the

top five to eight inches from the “main stem” (that includes the leaves and flowers), “terminal

bud” (that occurs at the end of a stem), ”or “central cola” (cut stem that could develop into a bud)

of the flowering top of the plant.

6. States and Tribes are required to include performance-based sampling protocols in the plan

submitted to USDA for approval if they decide to use this methodology.

Standard Sampling Protocols:

1. The standard sampling method must be used by all producers, except for producers operating

under a State or Tribal plan that includes a performance-based sampling requirement.

2. The standard sampling protocol ensures, at a confidence level of 95 percent, that no more than

one percent of the plants in each lot would exceed the acceptable hemp THC level and ensures

that a collected sample represents a homogeneous composition of the lot.

3. Every lot and every producer must be sampled and tested.
4. All samples must be collected from the flowering tops of the plant by cutting the top five to

eight inches from the “main stem” (that includes the leaves and flowers), “terminal bud” (that

occurs at the end of a stem), or “central cola” (cut stem that could develop into a bud) of the

flowering top of the plant.

5. All producers licensed directly by USDA are subject to these requirements.

Equipment and Supplies:

1. Garden pruners/shears (Cleaned prior to and following each composite sample. Some

examples of appropriate cleaning agents and supplies to use on garden pruners/shears are bleach,

rubbing alcohol, steel wool, and/or sandpaper.)

2. Sample bags, paper.

2.1. The size of the bags will depend upon the number of clippings collected per lot.

2.2 The bags should be made from material known to be free from THC.

3. Security tape

4. Permanent markers

5. Sample collection forms

6. GPS Unit of lot being sampled

7. Disposable gloves – Nitrile

8. Ladder

Sampling Guidelines:

1. The licensee or designated employee should be present throughout the sampling process, if

possible.

2. Surveillance of the growing area.

2.1. The sampling agent should estimate the average height, appearance, approximate density, 

condition of the plants, and degree of maturity of the inflorescences (flowers/buds). 

2.2. The sampling agent should visually establish the homogeneity of the stand to establish that 

the growing area is of like variety. 

3.Time of Sampling:
3.1. Within 30 days prior to the anticipated harvest of a designated hemp lot, an approved 

sampling agent, State or Tribally designated person or Federal, State, local, or Tribal law 

enforcement agency shall collect representative samples from such cannabis plants for THC

concentration level testing. 

4. Field Sampling:

4.1. The licensee or designated employee should accompany the sampling agent throughout 

the sampling process, if possible. 

5. Surveillance of the growing area.

5.1 The sampling agent should verify the GPS coordinates of the growing area as compared

with the GPS coordinates submitted by the licensee to USDA.

5.2 The sampling agent should estimate the average height, appearance, approximate density, 

condition of the plants, and degree of maturity of the inflorescences (flowers/buds). 

5.3 The sampling agent should visually establish the homogeneity of the stand to establish

that the growing area is of like variety.

6. Time of Sampling:

6.1 Within 30 days prior to the anticipated harvest of a lot a sampling agent should collect

representative samples from such a lot for THC concentration level testing.

7. Field Sampling:

7.1 For purposes of determining the number of individual plants to select for sampling, the size 

of the growing area should be considered. For sampling purposes, samples from separate lots 

must be kept separate and not be comingled. 

7.2 For lots of less than one acre, including greenhouses, select a minimum of 1 plant, then take 

a cutting from the plant to form a sample. For lots of 1 to 10 acres, including greenhouses, follow 

the chart in example 2 below, take cuttings of each plant, then combine to form a composite 

sample. 

7.3 For growing areas larger than ten (10) acres, including greenhouses, the number of plants 

that should be selected to form a composite sample is based upon the Codex Alimentarius 

Recommended Methods of Sampling for the Determination of Pesticide Residues for 

Compliance with MRLS CAC/GL 33-1999. 

7.4 The sample size is estimated in a two-step process. The first step is to estimate the 

number of primary plants to be sampled. The second step is to adjust the estimate of primary

plants by the acreage under cultivation.
The initial number of primary plants is estimated using:

where p is the confidence level to detect hemp plants testing above the acceptable THC threshold 

and i is the proportion of hemp plants having THC content above the acceptable threshold. The 

values for i are based on past experience in the same or similar growing areas and should be 

consistent with the requirements currently in the Final Rule.

The initial primary plants estimate is adjusted by the number of acres to calculate the minimum 

number of primary plants as follows: 

where n is the minimum number of primary plants to be selected for forming a composite 

sample, n0 is the initial number of primary plants estimated using the previous formula, and N is 

the number of acres under cultivation. 

Examples 1 and 2 below describe the minimum number of samples that must be collected in

order to meet the 95% confidence level requirements in the Final Rule. If a State or Tribal hemp 

program does not have data from a prior growing season to determine the i value, the sampling 

charts below may be utilized. State and Tribal hemp programs are free to include more rigorous 

sampling requirements, or to develop performance-based requirements. 

Example 1: The initial primary plant sample size is 299 with a confidence level of 95% to detect

hemp plants having an acceptable hemp THC level and a proportion of hemp plants having THC

content above the acceptable threshold equal to 0.01 is considered appropriate. The adjusted 

primary plant sample sizes for fields from 11 to 173 acres in size are shown in the following 

table:
:-

,-

:

:

:

:-

i-

:-

i-

:-c

:

:-

:-

i-

:-

i-

-

Number 

of acres

Sample

Size

11 11

12 12

13 13

14 14

15 15

16 16

17 17

18-19 18

20 19

21 20

22 21

23 22

24 23

25-26 24

27 25

28 26

29 27

30 28

31-32 29

33 30

34 31

35 32

36 33

"' 37-38 34

39 35

Number

of acres

Sample

Size

40 36

41-42 37

43 38

44 39

45-46 40

47 41

48 42

49-50 43

51 44

52 45

53-54 46

55 47

56 48

57-58 49

59 50

60-61 51

62 52

63-64 53

65 54

66-67 55

68 56

69-70 57

71 58

72-73 59

74 60

Number

of acres

Sample

Size

75-76 61

77 62

78-79 63

80-81 64

82 65

83-84 66

85-86 67

87 68

88-89 69

90-91 70

92 71

93-94 72

95-96 73

97-98 74

99 75

100-101 76

102-103 77

104-105 78

106-107 79

108 80

109-110 81

111-112 82

113-114 83

115-116 84

117-118 85

Number

of acres

Sample

Size

119-120 86

121-122 87

123-124 88

125-126 89

127-128 90

129-130 91

131-132 92

133-134 93

135-136 94

137-138 95

139-140 96

141-143 97

144-145 98

146-147 99

148-149 100

150-152 101

153-154 102

155-156 103

157-157 104

159-161 105

162-163 106

164-166 107

167-168 108

169-170 109

171-173 110
Example 2: The adjusted primary plant sample sizes for fields from less than 1 to 10 acres in size 

are shown in the following table: 

7.5 Sampling agents should always walk at right angles to the rows of plants if possible, 

beginning at one point of the lot and walking towards another point on the opposite side of the 

lot. If the lot is too dense for this to be possible, the sampling agent should take all reasonable 

steps to ensure that a sample is collected that represents a homogeneous composition of the lot 

by avoiding edges and thoroughfares. 

7.6 While walking through the growing area, the sampling agent should cut at least “n” 

inflorescences (the flower or bud of a plant) based on the acreage of the growing area, at random 

but convenient distances. Avoid collecting sample specimens from the borders of the 

field/greenhouse.

7.7 The cut should be obtained from the flowering tops of plants when flowering tops are 

present and shall be approximately five to eight inches in length from the “main stem” (that 

includes the leaves and flowers), “terminal bud” (that occurs at the end of a stem), or “central

cola” (cut stem that develops into a bud) of the flowering top of the plant. 
7.8. Utilize paper sample bag(s) for collecting sample cuttings. Ensure that each bag has the 

minimum number of cuttings, n, as calculated by 7.4, or in the Example Tables 1 and 2. If one bag 

cannot accommodate the minimum number of cuttings due to lot size, the sample may be divided 

into multiple bags, but must be clearly labeled in such a way that each bag is appropriately matched 

with the corresponding lot. (i.e. For lot 101 with three corresponding sample bags: 101 1 of 3, 101 2 

of 3, 101 3 of 3.) 

7.9. Seal each bag and record the sample number or other documentation as required by the State or 

Tribe.

7.10 A sampling protocol must have the potential to ensure, at a confidence level of 95 percent,

that the cannabis plants will not test above the acceptable hemp THC level of 0.3 percent on a 

dry weight basis. 

8.Sample identification:

8.1 The sampling agent should seal each bag and record the sample identification number. The 

sample should also be identified with the following information: Sampling agent contact information; 

name and contact information of the producer; producer hemp license or authorization number; date 

of sample; and lot, subfield, or other identifier as provided by the USDA Farm Service Agency; any 

other information that may be required by States, Tribes, Law Enforcement Authorities, mail 

delivery services, customers, or groups of customers. 

Note: In accordance with 7 CFR 1.901(e), the contents of this document do not have the force and effect 

of law and are not meant to bind the public in any way, and the document is intended only to provide 

clarity to the public regarding existing requirements under the law or agency policies.