Tuesday, February 22, 2005




Compost tea is ancient. You can find references to it in texts dating back to the Roman Empire (Cato's De Agricultura). So says a real doyenne of dirt, microbial ecologist Elaine Ingham, who wrote this to Ketzel Levine in a recent e-mail:

(Cato the Critic) describes a liquid extract of compost. He also describes adding slaves' blood to the liquid applied to the vines. We would add liquid fish today to get a similar effect.
In the 20th century, compost tea makers preferred the Sock Approach. The recipe went something like this: Fill old sock with compost or manure, immerse sock in pail of water, let steep. When color is sufficiently brown, apply to plants.

But that's way too simple for the 21st century. We now take a more microbially balanced view of things (and, wouldn't you know it, a more marketable one). The Sock Approach, after all, left many with nasty-smelling brews that contained as much bad bacteria as good. So, folks in the field applied themselves to compost tea mixes with just the right combination of microorganisms.

As Elaine Ingham puts it, "Tea works because of the biology in it. If you don't have the necessary biology, you can't get all the benefits."

The benefits are well worth the effort, advocates say. We're talking pest and disease control on leaves (compost tea as foliar spray), bigger and better vegetables (compost tea as muscle juice), compost tea for soil detoxification (to undo the damage you've already done with chemical-based pesticides and synthetic fertilizers), and ultimately, for enhancing soil structure.

Few would argue against the wisdom of adding yummy bacteria, fungi, protozoa and nematodes to the soil. Certainly, compost tea is one way to add them.

But Elaine Ingham does argue that there are charlatans in the biz.

Without naming names, she's not entirely thrilled with some of the commercial brewing kits on the market. She says the tea they make lacks the right mix of microorganisms, and are ineffective. She fears that people will abandon the whole idea of compost tea after sinking time and money into products that are duds.

I brewed up about six gallons of compost tea using the SoilSoup brew machine. I applied several cups of the stuff to strategic plants throughout my garden. I don't expect to see much of anything happen until next spring, and even then, since my soil isn't exactly dust to begin with, I'm not sure I'll see much of a difference.

Nevertheless, I have had my fair share of foliar diseases this year and just a few too many pests, so I'm willing to overcome my general reluctance to intervene (read: lazy gardener), and will continue to experiment with the brewer. No doubt, after the dew-good fades, I'll probably go buy some organic pre-mix and just follow directions. Bottom line, however good it is for me, I've always hated to cook.

Additional Resources:

SoilSoup is the manufacturer of the compost brewer we used in our demonstration. They offer a pretty lively (if decidedly commercial) Web site with useful links.

The Soil Food Web is the brainchild of microbial ecologist Elaine Ingham, author of The Compost Tea Brewing Manual (3rd Edition). You could dawdle here for hours. Skeptics rejoice, she is no-nonsense about her field, as evidenced by her reviews of microbe-brewers.

BBC Laboratories is another micronutrient-rich site and research lab. Love their summary guide for microbial analysis; amaze and impress your friends.

Woods End Research Laboratory is the oldest compost testing lab in the U.S. Stop here to learn about using compost to detoxify soil (a.k.a., bioremediation).

In the best name category, the makers of the Microb Brewer win hands down. Good links page, too.

Some of these links are a bit beyond the casual home-brewer and cater to professionals, but are worth visiting if you're interested in sustainable agriculture.

Alaska Giant: The slideshow will make you a little nuts, but John & Mary Evans clearly mean well with their mail-order compost kits for the home gardener. You can sample their brew at Landscape Supply in Palmer, Alaska. Honest!

Compost Tea: EPM Inc. manufactures both compost tea brewers and vermicomposting systems (remember the worms?).

Growing Solutions, Inc., another brewmaker. Need a 500-gallon tank?

Earthworks wins the good deed award for selling compost tea machines to dozens of U.S. golf courses. Feed your head? Way dated. Now it's Feed Your Soil.

If you've made it this far, here are a couple of articles:
Linda Chalker-Scott, from the Center for Urban Horticulture in Seattle, weighs in on the myths of compost tea.

Homemade compost tea instructions from Organic Gardening.
Here's a succinct article by Elaine Ingham about compost tea, published in the (now defunct) Kitchen Gardener.

[If you want to know more about compost tea, just visit Ketzel Levine's page at: who compiled this information]


At March 19, 2008 at 11:49 AM, Blogger Paz said...

People should learn more about energy alternatives like electric cars. The new ones coming out are way better than gas cars. One of the main electric car companies, Zap, has delivered more than 100,000 electric vehicles (source: EV’s cost 1 to 3 cents per mile to run, compare that to regular cars!


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