If a soil test report indicates levels of some nutrients are high or excessive, select products containing lower concentrations of these nutrients. Further applications of organic materials containing these nutrients may create an imbalance and reduce plant growth. Slow growing plants and xeriscapes can be fertilized with a moderate availability material. Materials with slow to very slow nutrient availability, while good sources of organic matter, generally make poor sources of nutrients for most plants. The variety of organic fertilizers on the market means the homeowner can find a product to meet any need.
Organic fertilizers vary considerably in price.
Bulk quantities of organic materials are less expensive than small packages and should be purchased when fertilizing large garden and landscape areas. Calculate the amount of organic fertilizer needed by using the soil test nutrient recommendation, the concentration of nutrients in the fertilizer selected, and the size of the area fertilized. Garden and landscape areas are usually different than 1000 square feet. Estimate the size of the area to be fertilized by pacing or using a measuring tape to determine length and width. Multiply length by width to calculate area.