http://www.chicagotribune.com/features/home/chi-0212280312dec29,1,4685004.story
Tea and fertilitySome gardeners swear by a potion brewed to boost soil and banish bad bugs -- harmlesslyBy Adrian HigginsThe Washington Post December 29, 2002 In a Virginia field, 50 organic gardeners gather around Elaine Ingham for what is likely to be the weirdest cooking demonstration they have ever seen. Ingham's dark, bubbling brew is not from the garden but rather for the garden. Into a 35-gallon kettle of water she has thrown measured amounts of dried seaweed and an inky liquid called humic acid. "We have got loads of good stuff going into the mix," she says, filling a nylon sock with screened compost and earthworm castings. Soon, this "tea bag" is submerged in the water and bombarded by bubbles produced by an air pump. This is neither high cuisine nor dark sorcery, but the latest innovation in the world of organic gardening and farming. Liquid fertilizers made from manure and compost, simply soaked in a bucket of water for a few days, have been around for centuries. What's new are the bubbling technique and specific ingredients, which cause the growth of beneficial microbes that displace and even go after all the bad spores and germs that prey on and kill plants. Spray the tonic on the leaves and the bad bugs have nowhere to land, say advocates. Pour it on the soil, and you form a protective barrier for the root zones. Enthusiasts say that when used repeatedly, the tonic revitalizes soil and allows the cultivation of plants without the need for chemical fertilizers and pesticides. Among the testimonials: roses that never get black spot; thick, green turf grass; ornamentals of amazing vigor and health--all without the use of environmentally harmful chemical fertilizers and pesticides. Organic farmers are using the tea to repair strawberry fields rendered lifeless by toxic fumigants. Growers of crops such as potatoes have seen greater yields using no chemicals. Some are even spraying it from crop dusters, said Ingham, a soil scientist and consultant to organic farmers. She heads a laboratory named Soil Foodweb Inc., based in Corvallis, Ore. (www.soilfoodweb.com). An early pioneer of the technology, she is regarded as a leading light in organic gardening and farming circles. Scientists skeptical Not everybody is convinced. "I have a lot of colleagues rather concerned about the hype," said Linda Chalker-Scott, an associate professor at the Center for Urban Horticulture at the University of Washington. "We are all waiting for the science behind the claims." Ingham and other scientists who advocate the product say lab tests reveal three basic beneficial aspects of compost tea: plant nutrients; biostimulants such as enzymes and amino acids; and beneficial bacteria, fungi and nematodes (wormlike animals) that suppress disease and also may fight plant pests. Chalker-Scott said Ingham is "an extremely good soil scientist," but her data have not yet been subjected to sufficient review by other scientists. One of the problems, said Chalker-Scott, is that every batch of compost tea seems to produce different results, making it difficult to conduct more definitive studies that might isolate the merits of one microbe over another. Another concern is that the brewer might inadvertently create a brew containing E. coli bacteria. Ingham says this is a valid concern but only if correct steps are not observed. Any compost containing animal manures should be thoroughly composted at 130 degrees for 10 days. A soil thermometer can tell you if your pile gets hot enough. Alternatively, use compost not made with animal manures or use earthworm castings, she said. They are sold in bags at garden centers. Spreading the word If the scientists are squabbling, gardeners, farmers and manufacturers of equipment and supplies are forging ahead. "When it comes to things in organic farming, in general, the farmers tend to be quite a few years ahead of the scientists," said Steve Diver, an agricultural specialist with Appropriate Technology Transfer for Rural Areas, a non-profit funded by the U.S. Department of Agriculture that provides technical advice to small farmers. He said compost tea has yielded remarkable results. When it was used on a field of bell peppers succumbing to viral disease--usually a death knell in the vegetable garden--it not only stopped the virus in its tracks but also allowed infected plants to recover. "This is absolutely mind-boggling that an organic approach was able to arrest a virus and get the crop to grow out," he said. Diver said, if you were to look at a leaf through a microscopic hand lens, you would see hairs so thick that they resemble a jungle. By coating all those surfaces with compost tea, the good microbes provide a barrier to any bad ones that want to feed on the plant. "There's no room for them, there's no food for them, and they are knocked out of the loop," he said. Preparing the brew Gardeners prepared to make a trip to the pet store can make their own brewing kit using aquarium equipment. Ready-made versions, some costing in excess of $1,000 and geared to commercial customers, are also available. Some manufacturers are getting into the homeowner market. SoilSoup (www.soilsoup.com) makes a 6.5-gallon brewing kit priced at $329, plus shipping and handling, and has started selling commercial dispensers to garden centers, where customers can arrive with their own containers and fill up for a fee. Another company, Keep It Simple Inc. (www.simplici-tea.com), makes a 5-gallon kit for the home gardener for $99.50, plus shipping and handling. Mary Robson, an extension agent in Renton, Wash., said gardeners have made non-bubbly compost teas for thousands of years for their nutrient values alone. In the Pacific Northwest, where the brewed article has taken off among gardeners, "we all want it to work," said Robson. "We don't know exactly whether, or if, it does. At least, I don't." How to make your own Commercial brewing kits for compost tea can cost $99.50 to $8,000, depending on size and equipment. But soil scientist and compost tea guru Elaine Ingham says you can assemble your own kit. If you do not have a hot compost pile, you can use earthworm castings. These, along with powdered kelp and humic acid, are available from many garden centers. Equipment 5-gallon plastic bucket aeration pump for 70-gallon aquarium tubing, connectors and two or three air stone bubblers (these supplies are available at pet or aquarium stores) nylon knee sock Ingredients water 1/2 pound earthworm castings or screened compost from a hot pile 1 to 2 fluid ounces each: liquid molasses, dried kelp and liquid humic acid Directions 1. Place air stones in the bucket, but keep the air pump outside and dry. Fill the bucket with water. Run the pump for an hour to allow the chlorine in the water to bubble out. 2. Add the molasses, kelp and humic acid. Fill the sock with castings or compost, leaving enough space for the material to move around. Knot the sock. Either place the sock loose in the water or brace it with wire so that it hangs submersed and directly beneath the air stones. 3. Run the pump for 24 hours to allow the liquid to brew fully. Using the brew Pour the mixture into a garden sprayer and use as a spray on leaves. For the growing season, Ingham says, spray two weeks before plants start growing, at a rate of 10 gallons to the acre. Then spray at 5 gallons to the acre every 10 to 14 days for three months "or until you see no more disease." Then spray monthly. In the third year of doing this, she says, you need only spray three times annually. Or, apply the compost tea directly to the soil around plants. Safety considerations The equipment must be cleaned and disinfected between brewings to prevent the subsequent brewing of bad bacteria, which can damage plants and even create a health hazard. Foul odors from the finished mix signify a batch that contains unwanted bacteria. -- Adrian Higgins Copyright © 2002, Chicago Tribune To unsubscribe from this group, send an email to: compost_tea-unsubscribe@yahoogroups.com Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. |