Compost tea is a compost extract brewed with a microbial food source such as molasses, kelp, rock dust, humic-fulvic acids. The compost-tea brewing process extracts and grows populations of beneficial microorganisms.
Compost tea is used for two reasons: To include microbial life into the soil or onto the foliage of plants, and to add soluble nutrients to the foliage or to the soil to feed the organisms and the plants present. The use of compost tea is suggested any time that the organisms in the soil or on the plants are not at optimum numbers. Chemical based pesticides, fumigants, herbicides, and some synthetic fertilizers kill a wide range of beneficial microorganisms that encourage plant growth, while compost teas improve the overall life in the soil and the surface of plants. High quality compost tea will inoculate the leaf surface and soil with beneficial microorganisms, instead of killing them.