compost tea

Compost Tea, a liquid solution or suspension made by steeping compost in water. It is used as both a fertilizer and as in attempts to prevent plant diseases.

Types

There are several kinds of compost tea, depending on the method and ingredients with which the tea is made:

Fresh Compost Tea

Made by steeping compost in water for a brief period, then applying the liquid.

Modern Compost Teas

These consist of aerobic mixtures made by adding compost (and some extra nutrients to feed its microbes) to dechlorinated water and aerating the mix for one or two days. This process encourages aerobic bacteria and fungi. The mixing, or active aeration, brings old-fashioned anaerobic compost teas into the modern era; it is also what keeps compost teas aerobic, and thus safe. If the tea is properly made, it is a concentrate of beneficial aerobic microbes.

Actively Aerated Compost Teas

These are usually easy to apply and are put right where they are needed. They are a fast, inexpensive, and fascinating way to manage soil food web microbiology in the yard and garden.

Do not confuse actively aerated compost tea with compost leachates, compost extracts, or manure teas, all of which have been employed by farmers and gardeners for centuries. An "AACT" compost tea implies a focus on promoting the growth and extraction of beneficial aerobic microorganisms. Disolved oxygen levles in an AACT must always be maintained above 6%.

Fermented Compost Tea

Also known as Anaerobic Compost Tea, is made by leaving compost and water in a container for a period of several days, allowing oxygen levels to drop well below 6% dissolved oxygen encouraging anaerobic microbial growth. The end result is an anaerobic soup with perhaps a bit of aerobic activity on the surface. The loss of aerobic microbial diversity (not to mention the risk of its containing anaerobic pathogens and alcohols) suggests that application of fermented teas will most likely have a detrimental effect on any plant.

Compost Leachate

Compost leachate is the liquid that oozes out of compost when it is pressed or when water runs through it and leaches out. These concoctions get a bit of color and may have some nutrient value, but leachates do little to impart microbial life to soil..

Manure Tea

This is created by suspending a bag of manure in water for several weeks, is also anaerobic. Using manure is asking for pathogenic problems and, especially under anaerobic conditions, virtually assures the presence of E. Coli. In order to keep beneficial microbes working in the soil, the compost tea must be kept aerobic.

See also

• Effective Microorganisms
• Composting

References

Lowenfels, Jeff and Wayne Lewis. Teaming with Microbes: A Gardener's Guide to the Soil Food Web. Timber Press: Portland 2006 ISBN 978-0-88192-777-1

External links

• Compost Teas for Plant Disease Control: Production, Application, and Results ASA-CSSA-SSSA Annual Meeting, Denver, CO, Nov. 5th, 2003 Steven Scheuerell and Walter Mahaffee, Department of Horticulture, Oregon State University

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