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Know you the Magic of Compost Tea !
Gardeners have been making compost and manure tea for many years — probably even for many centuries. Compost tea is easier to apply than dry compost and it’s also a good way to make a small amount of compost go much further. Brewing methods are typically very low-tech: Put some compost in a bucket with water, let it sit for a few days and then apply.
Elaine Ingham and her team are developing crop-specific compost teas that can be used on a commercial scale. Soil biologist Dr. Elaine Ingham has spent the past 15 years studying compost and especially compost tea. She has devoted her professional career to learning about the complex web of bacteria, fungi, protozoa, nematodes, microarthropods, earthworms and other soil critters that work together to feed plants, fight pathogens and pests, and improve soil texture.
Dr. Ingham refers to this web of soil life as the “soil food web.” The research being conducted by her company, Soil Foodweb Inc., is yielding some fascinating discoveries.
Here are some of the highlights:
For best results, compost and compost tea should be produced in an oxygen-rich, aerobic environment. This ensures that the finished product will be rich in nutrients and beneficial organisms. When compost (or compost tea) is made in anaerobic conditions, nutrients are lost to the atmosphere(which is why anaerobic compost stinks). The end product of anaerobic decomposition may also contain alcohol, phenols, and organic acids that are toxic to plant tissues.
The most productive soils in the world are those that contain the most organic matter. This wealth of organic matter can be used by beneficial bacteria, fungi, protozoa, nematodes, and microarthropods to build soil structure and feed plants. Productive soils always contain an abundance of beneficial bacteria, but the world’s most productive soils also contain a rich diversity of fungi — 1,000 times more fungal biomass than bacterial biomass.
The soil food web that’s ideal for growing a lawn is different from the soil food web that’s right for vegetables or shrubs. Dr. Ingham has found that most flowers and vegetables grow best in soils that are dominated by bacteria rather than fungi. To produce tea with a high level of beneficial bacteria, you need to start with compost that’s been made with about 45% green materials, 30% woody and 25% high-nitrogen materials.
Compost tea used on lawn
This Oregon lawn was sprayed in June, and by August, the benefits of compost tea are clear.
Compost tea has proven to be valuable as a foliar spray as well as a soil drench. When leaf surfaces are coated with a layer of beneficial bacteria and fungi, “bad” bacteria and fungi are overcome and are prevented from infecting the leaves. Coating leaf surfaces with compost tea increase the biological activity on the leaf surface, which also lengthens the time plant stomates are open. This increases the opportunity for nutrient uptake, which improves growth and boosts yields.
Dr. Ingham’s organization, Soil Foodweb, Inc., has a commercial lab that will test compost and compost tea to determine the numbers, types, and activities of each important group of microbes. They can test for active bacterial biomass, total bacterial biomass, active fungal biomass, total fungal biomass, protozoan numbers, nematode numbers and community structure, and mycorrhizal root colonization.
In an aerobic environment, the microbes in compost tea will multiply exponentially.
Foam should start appearing on the surface after just 12 hours. With adequate aeration, compost tea will reach its “richest” state (most biologically active) in just 24 hours. Circulating the water and maintaining a high level of dissolved oxygen is important. Dissolved oxygen levels should be above 6.0 parts per million. Gentle agitation of the “tea bag” (which contains the compost) is necessary to release the multiplying fungi into the tea solution.
Dr. Ingham’s soil research is attracting more and more attention each year. She and her team are now working in Africa, Central America, Australia, Holland and almost every state in the U.S., devising crop-specific compost teas to improve a wide range of difficult soil conditions.