Compost tea
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Compost Tea, a liquid solution or suspension made by steeping compost in water, puts necessary microbes back into the soil—it has a very short shelf life.
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[edit] Types
There are several kinds of compost tea, depending on the method and ingredients with which the tea is made:
[edit] Fresh Compost Tea
Made by steeping compost in water for a brief period, then applying the liquid.
[edit] 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.
[edit] 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.
[edit] 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 a build-up of anaerobic bacteria and fungi to chemically alter the mixture. A compost extract occurs when compost soaks in water for a couple of weeks or more. The end result is an anaerobic soup with perhaps a bit of aerobic activity on the surface. The loss of aerobic microbial diversity alone (not to mention the risk of its containing anaerobic pathogens and alcohols) suggests that compost extracts are not worth the effort.
[edit] 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.
[edit] 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.
[edit] Controversy
There is absolutely no scientific evidence that aerated teas have more benefit than non aerated. There is no scientific evidence that the bacteria brewed in any tea survive once applied to plants/soil[citation needed].
Many studies have shown no effect from the use of teas and others show harmful effects while some show positive effects. There is no difference in the effects noticed in the studies between aerated and non aerated teas[citation needed].
[edit] See also
[edit] 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
