Chapter 10

Compost Management on Organic Farms

Compost Teas

Compost tea is a liquid extract of compost that contains plant growth compounds and beneficial microorganisms. A primary reason for producing compost tea is to transfer microbial biomass, fine particulate organic matter, and soluble chemical components of compost into an aqueous phase that can be applied to plant surfaces and soils in ways not possible or economically feasible with solid compost. While compost tea is made in a variety of ways, all methods are similar in having water as the first, and compost as the second, most abundant starting materials.

Application of Compost Tea

Compost tea can be applied to the soil or directly to the plant as a foliar spray. When it is used as a foliar application, it is best to strive for thorough leaf coverage using a fine mist.

National Organic Program Standards for Compost Tea

Producers of any agricultural commodity or product certified as organic under the National Organic Program (NOP) must meet the fundamental requirements for processing and applying plant and animal materials for soil fertility and crop nutrient management practices as described in Section 205.203 (c) of the final regulation. The Rule does not specifically mention compost tea. The National Organic Standards Board (an advisory board to the National Organic Program) provided guidance in the use of compost teas, which can be found in the “NOSB Recommendation for Guidance: Use of Compost, Vermicompost, Processed Manure and Compost Tea.” Some of the recommendations are as follows:

Click on the following topics for more information on compost management on organic farms.