By Royce Hall
The idea of using decomposing matter (compost) in gardens and managed soils is not a new one. People have been utilizing the benefits of compost for centuries. However, in the past few decades there has been a great deal of advancement and research on liquid compost products, known as compost teas.
What is Compost Tea?
It can be helpful to think of compost tea as a liquid suspension of beneficial microorganisms and minerals. Compost tea is created by taking good quality compost (usually from leafy and woody material) and vermicompost (worm castings), then “brewing” the tea with a mixture of natural food products, such as kelp, fish hydrolysate (ground up fish), humates (rich black completely decomposed organic matter), and molasses in several gallons of water. Tea brewers are designed to continuously aerate this liquid mixture for 12-48 hours. This process extracts the beneficial microbes (bacteria, fungus, nematodes, and protozoa) from the compost and encourages them to multiply, resulting in an extremely concentrated mix of microbes, as well as some minerals extracted from the compost. The idea behind compost tea is that you can gain the benefits of compost without the laborious work of spreading compost.
Natural Nutrition – In nature, microbes break down organic matter, making the nutrients in the organic matter available to plants. By adding compost tea to your lawn or landscaped area, you can assist natural nutrient cycling. For maximum benefit, it is best also to add organic matter to your lawn or landscaped area for the microbes to eat. This can be done with compost, mulch, feed products (corn gluten meal) or fertilizers that have organic matter in them.
Micronutrients – Compost is very rich in micronutrients, like iron or manganese. Depending on the compost that goes into the tea, the mixture will contain many of these essential nutrients.
Diversify microbial life – While the soil is chocked full of microbes, sometimes a particular plot of land may be lacking in a particular variety of microbe which the compost tea can supply.
Disease control – A lot of research has been done on the preventive and curative effects of foliar compost tea applications (like this one). The basic idea is that the good microbes populate a plant’s leaf and prevent pathogens from settling down on the targeted plant. For best results, the compost tea must be applied frequently (every 7-10 days in some circumstances).