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Fall's the time to start and turn a new compost pile, and to spread mulch from old compost on the ground in a 2 to 3 inch layer. This helps to prevent winter weeds, slows down rain run off, and helps to improve soils for spring planting. If the garden has poor soils, applying compost helps in a number of ways. Apply it now for winter benefits. Compost tea doesn't compensate for the need for organic material in soils. Be sure to amend the soil well when preparing a new planting bed.
Remember the reminder about planting trees. Tree roots establish themselves better if they are planted into the native soil. When you plant one tree, just remove the soil and plant. If the area drains poorly, do plant the tree on a slight berm, above grade, to enhance the drainage. Do not add peat moss or compost to the planting hole, but do use it as mulch after planting.) If you do prepare an entire planting area, such as a new landscape, incorporate organic matter deeply and thoroughly throughout the whole space.
When the spring growing season starts, the fall compost pile may have broken down sufficiently to brew some compost tea. Compost tea is a new/old concept that's getting lots of interest by farmers and gardeners. In essence, compost tea results when fully composted materials are steeped in water. The resulting liquid, which may be quite aromatic depending on the type of material, is applied to plants to improve growth and to increase the number of soil microorganisms around the plant roots.
Using compost tea was part of farming technique centuries ago, when animal manures were steeped in water and the resulting liquid was poured around plants. Some changes in the method of production have currently given the tea idea a high-tech twist. New equipment, somewhat more expensive than would be practical for the average gardener, results in a tea with more oxygen incorporated, super-oxygenated through air being incorporated while the compost ferments.
Compost tea can improve soil quality by increasing the number of beneficial soil organisms. Plants depend on soil microorganisms for help with gathering and incorporating nutrients in their roots. Plants can't take up all the nutrients they need for growth. They must rely on tiny organisms to convert the nutrients into forms they can use. Compost teas contain substantial quantities of microorganisms, which are released into the soil when the tea is added around plants.
If you want to experiment with compost teas, they have traditionally been made by a fermentation process. A backyard gardener can make a simple compost tea using a method promoted by Will Brinton at Woods End Agricultural Institute. High quality (fully decomposed) compost is covered with tap water at a ratio of 1 part compost to 5-8 parts water. If your water system contains added chlorine, allow the water to sit out overnight to improve the survival of the live bacteria in the compost. Still the tea and allow it to ferment at temperatures between 59° and 68° F. (You can see that this is a spring/summer project, not winter.) The fermentation period can be from 3 to 21 days. Then the mixture is strained out and applied to plants with a sprayer. Or it can be poured into the ground around the roots. Experimenters report stronger plant growth, not necessarily from the nutrients added (which are few) but from the increase in microorganisms available to the soil. Use the mixture as soon as possible when it's ready.
Other experiments now look at the potential of compost teas to manage fungal diseases. Research done in the eastern United States, by AATRA (Appropriate Technology Transfer for Rural Areas), has reported some effectiveness of compost teas for common fungal problems such as gray mold on beans. Locally, very little firm research evidence has come out. Landscapers at the City of Seattle Parks Department, Seattle University, and the University of Washington have experimented during the past summer with compost tea to improve plant growth and to attempt disease control. Results have been mixed and more research is planned.
Many unanswered questions remain about this new/old garden technique. What individual microorganisms are present and working? How often should it be applied? Which fungal organisms can it control? More information is definitely needed. But the technique is gaining enough attention that you may find yourself reading about it in gardening publications.
If you want to pursue more information on this, check out the following web sites. Compost Teas for Plant Disease Control at AATRA. You can check out aerobic tea brewers at Growing Solutions Inc. and Soil Soup Compost Tea .
Hortsense: Managing plant problems with Integrated Pest Management
