Feed Your Food Web
Compost Tea Strengthens Plants, Defends Against Disease.
By Rachel Foster Undated

All last year, while controversy over GM foods grabbed headlines, news items popping up in the gardening media suggested that another, more heartening revolution was quietly taking place in commercial agriculture: the benefits of compost. Compost protects grapes from the deadly phylloxera. Compost can replace methyl bromide fumigation to keep strawberry fields healthy. Apple growers in Washington find mixing a bushel of hardwood bark compost in planting holes suppresses "at least one soil-borne disease." In Ohio and Australia, composted bark stops root rot in nursery container plants.
Intrigued, I turned to the Internet for a closer look. That first foray not only pulled up an avalanche of information but also introduced me to a hyperactive soil scientist in Corvallis and a sophisticated business right here in West Eugene.
Most gardeners know that compost improves soil quality and raises healthier plants. We may not know much about how it works, but we use it anyway. Not only does it yield visible results, it is a convenient way to dispose of organic waste. Now research is showing that the more we know about the contents of our compost, the greater the benefits we derive from it.
One person who is spreading the word about compost function and its relationship with soil is scientist and businesswoman Dr. Elaine Ingham, the energetic director of Soil Foodweb Incorporated. Ingham has worked for years with strawberry growers in California, demonstrating that transplanting strawberries in plugs of compost eliminates the need for fumigation with methyl bromide, an ozone-depleting chemical that has been used in recent decades to rid the soil of pests and soil borne diseases. Compost both suppresses soil diseases and builds disease resistance in the plants themselves. What's more, compost can increase yields 1000 pounds per acre compared to methyl bromide treated fields.
To understand the methyl bromide story, you need to know about the "soil foodweb." That's Ingham's phrase for the complex of organisms in soil and their interactions with plants and their environment. Natural systems such as woodland or prairie are healthy and productive without inputs of pesticides and fertilizer because their soil foodweb is intact. A healthy foodweb maintains good soil structure, decomposes plant residues and constantly recycles and stores nutrients while making them available to plants. It also makes growth factors, and can consume pollutants such as synthetic pesticides.
Unfortunately, modern agricultural methods disrupt the soil foodweb. After decades of conventional tillage, monoculture and pesticide use, the foodweb and the soil are so degraded that crops become ever more dependent upon the addition of fertilizers and pesticides. The good news, as Ingham and others are showing, is that soil health can be restored with the use of compost, and that recovery can be surprisingly quick if you use compost with just the right combination of organisms and the right nutrients to feed them.
Even more exciting, the benefits of high quality compost are magnified when it is used to brew compost tea. Compost tea has been used for thousands of years. What's new about compost tea today is that we are learning to control its qualities so that it will be more effective in specific situations, so effective that it may help to make sustainable methods viable in mainstream food production.
Compost teas are applied either to the soil or to foliage. Tea applied to the soil will move into the root-zone where its nutrients will be used by the plant as well as by microorganisms in the soil. The beneficial organisms in the compost tea may also become part of the soil foodweb. Applied to foliage, compost tea acts as a rapid fertilizer. It can also confer a remarkable degree of resistance to fungal and bacterial diseases.
Now, to the gardener making compost tea at home, a bit of variation from batch to batch is not a big concern. To commercial growers, however, consistency is a big deal. If compost tea is to replace synthetic fertilizers and pesticides, it has to work as well or better, and it has to work every time. What's more, large-scale production requires a consistent product that is almost "off the shelf;" few farmers are going to rely on their own expertise in making consistent, high quality tea.
This is where Eugene businessman Michael Alms enters the story. Alms grew ornamental plants commercially in Hawaii for 14 years. When he moved to the mainland he saw, in his words, "a need to help in the transition to sustainable methods." Specifically, he found a niche for commercial-grade compost brewing machines. Growing Solutions was incorporated in 1997 and now ships the Microb Brewer all over the world.
The Brewer, available in 12, 50 and 500 gallon sizes, consists of a basket suspended in a conical container that holds water and nutrients. Growing Solutions supplies the machine, the nutrients in pre-measured packets, and high quality compost manufactured by collaborating businesses. (It's the compost that provides the micro-organisms, so a brew is only as good as the compost you put in.)
Why is the Microb Brewer better than a sack and a bucket? A unique circulation mechanism keeps the system well-oxygenated and ensures a homogeneous mix so nutrients are available throughout the brewing process. The oxygenation and blending, and addition of some nutrients beyond what is in the compost, permits very rapid expansion of micro-organisms in a 18-24 hour period. This concentrated brew must be used within 15 hours, before the micro-organisms die from lack of oxygen.
It appears that tea from the Microb Brewer is effective. "It was used on 15,000 acres of potatoes in Idaho last year," Alms says, "and all sorts of wonderful things happened: increased yields and quality, reduced chemical input." The city of Seattle's Parks and Recreation department uses it on their landscaping. Locally, Territorial Seed Company has been testing it at the London farm with good results, according to Josh Kirschenbaum. "We used it in many tomato trials last year and saw a very nice amount of disease resistance," he says.
Want to try it in your garden? Territorial lists the small brewer in their catalog, but at 12 gallons it's too large and too expensive for most home gardeners. In any case, you can get fresh compost tea this spring, brewed every night in the Microb Brewer, at both Rexius and Lane Forest Products. Call ahead to make sure they've started the brewer, and take along a gallon container. That's enough for a quarter-acre garden. To learn more than you ever needed to know about soil biology and compost, visit www.soilfoodweb.com