WHYY home



Guests and Research

Alphabetized Index of Garden Answers

Appearances & Events


Past Shows






  Mike's Gardening Tips

Supercharged Compost Tea: The ULTIMATE Disease-Fighting Plant Food?

I've been telling anybody who stood still long enough to listen over the past ten years that compost is the absolute best way to prevent or cure many of the nasty diseases that afflict plants. That's because compost is alive--and some of its helpful little organisms actually consume plant diseases directly. Compost is also the perfect fertilizer, and by providing all the nutrients your plants need, it helps to increase their overall health and vigor, making them much less attractive to pests and disease. And some of the organisms in compost even seem to boost the immune system of plants as well. That's three different ways compost prevents and fights dread plant disease!

And one of the easiest ways to get this great stuff right where its needed is to spray it onto your plants in the form of a 'tea'. Steep some high-quality compost in water for 24 hours, spray the resulting 'compost tea' on your plants early in the morning, and they'll get all the benefit of those disease-fighting little guys, AND absorb the nutrients in the tea right thru their leaves. (And any that runs off will be 'eaten' by the plants roots!)

Several years ago, researchers discovered that you could enhance the number and power of disease-fighting microorganisms in compost by fermenting the tea. Seems that the fermentation process produces lots of sugars and other nutrients that feed the microorganisms, creating super-powered disease fighters that can defeat REALLY bad actors, like black spot on roses.

Well, now there's a new kid on the block: Aerated compost tea. Word got around that if you let 'regular' compost tea sit after the fermentation had stopped, some of the microorganisms would begin to die from lack of oxygen. So West Coast gardeners began experimenting with pumping air into their brews with aquarium bubblers to keep more of those helpful little guys alive.

Then Ed Neff came along. Working in Seattle, Ed perfected this process, creating what he calls "Soil Soup" using a motorized blender to continually keep the steeping tea in motion as air is forced into the mixture. The science behind this is pretty strong: Keeping the little good guys who live in compost well-aerated can lead to amazing increases in their numbers (10,000 to 50,000 times as many as in the same size batch of non-aerated tea) and abilities. To feed and fortify all those garden helpers rapidly-multiplying in his beneficial brew, Ed also created a specialized 'bacterial nutrient solution'--a blend of high-nitrogen seabird and bat guanos with some other nutrients in a base of molasses.

I've been testing a home-sized Soil Soup machine this summer. The blender hangs on the side of a six-gallon bucket, reaching almost all the way down to the bottom; it really keeps that liquid moving and bubbling. You fill the 'tea bag' holder with two cups of high-quality compost (they supply a starter bag of worm compost), add six ounces of nutrient solution (also supplied), start 'er up, let it run for a day or two, and then spray the supercharged 'Soup' on your plants (or just water them with it). I fed three tomato plants a couple batches as a test, and have to admit they DO look bigger, happier and healthier than many of my others.

The home unit costs $329. A 25 gallon version, designed for large landscapes or small organic farms, costs $500. But Ed's pride and joy are the BIG machines: 175 and 500 gallon behemoths that he sells to nurseries, who brew up huge batches that they sell to local gardeners at $5 a gallon. Sorry--most are on the West Coast so far; the closest ones to us are in New York. But maybe some smart and savvy area nursery will see this, get in touch with Ed, and start 'making soup' next summer!

For more info, visit their web site: www.soilsoup.com, or call toll-free: 877-711-7687.

©2005 WHYY