‘Compost tea’ allows gardeners to brew greener pastures

By Steve Hill
University Week

Rather than choosing their poison, UW gardeners will instead be reaching for a spot of tea starting this spring.

But it’s not the kind of tea one sips from a cup.

In an effort to reduce pesticide use on campus, the UW grounds crew is turning to “compost tea” to protect the landscape’s roses, rhododendrons and much more. The organic concoction was used on a limited basis with success last year. Now the gardeners are ready to take the method virtually campus-wide.

Gardener Mike Erickson fills a bottle with “compost tea” made in the apparatus behind him.

“It’s basically a way to improve whole-plant health,” Liesl Zappler, a UW gardener and strong proponent of the compost tea, said. “It improves the soil quality by providing more microorganisms for the soil and the plant.”

The tea is brewed with organic material from the UW composting facility near the Ceramic Metal Arts Building. The Grounds Maintenance division purchased and began using a large compost tea brewer last year. The machine yields a safe, chemical free organic tea - a water-based compost extract - that promotes the growth of beneficial microorganisms in the soil and on plants.

That leads to grass and flowers, shrubs and trees that are more resistant to disease as well as healthy soil capable of thwarting annoying weeds.

Last year the brew proved useful in preventing powdery mildew in the large rose beds near Drumheller Fountain. While it’s too early to call the method a complete success, officials are cautiously optimistic.

“The jury is still out over the long-term efficiency of it,” Bonnie Taylor, Grounds Crew supervisor said. “Last year we cut way back on our fungicide treatments for the roses and we’re pretty optimistic about that. We’re still not sure about the ornamental fruit trees and the quad cherries. We’re not ready to risk our collection. One season doesn’t totally make a case for it, but we’re very hopeful.”

Others are hopeful too. The method has grown in popularity in recent years as an organic alternative to gardening and farming with chemicals. Locally, gardeners at Seattle City Light, Seattle City Parks, Seattle University, Seattle Tilth and Snohomish County are increasingly using the compost tea. But according to Zappler, the UW ought to be a leader both in using and promoting the compost tea.

The rose gardens by Drumheller Fountain have been treated without chemicals so far this spring.

“As a university, we really need to be more cutting edge with our horticultural practices,” Zappler said. “Moving away from pesticides and using alternative techniques not only is a better gardening practice, but it also helps us educate the public so they can take these practices home with them.”

A large number of homeowners use chemicals that may help in the short term, but over the long haul they kill too many beneficial microorganisms and are bad for the environment, according to compost tea believers.

Good compost teas, on the other hand, increase the number of beneficial bacteria in soil and plants. The tea also includes protozoa that feed on the bacteria, as well as beneficial fungi and nematodes - the more diverse microbes in the brew, the better.

Benefits of using the brew include disease suppression, an increase of nutrients in soil and plants, improved plant growth and, of course, fewer dangerous chemicals ending up in the air and water. But none of this suggests that all pesticides will be eliminated in the near future.

The UW has decreased its reliance on insecticides and avicides in recent years from almost 3,500 ounces in 1996 to less than 500 ounces in 2000. That doesn’t include similar reductions in the use of herbicides and fungicides. Those numbers could continue to decrease if the compost tea continues to work, the short term will continue to involve chemicals. But in the future, Zappler hopes the UW can be a totally organic campus.

“Compost tea isn’t a miracle cure,” Zappler said. “It’s more like taking a vitamin-C supplement.”

The effort on campus to reduce the use of dangerous pesticides in favor of the compost tea has also been good for the gardening crew, according to Zappler.

“If you just look at this job as ‘Weed that bed again, time to prune again’ and all these repetitive tasks without connecting it to something intellectual and educational, it would be a really dead-end job. But with all these new techniques, we’re definitely going to be better gardeners because we’re educating ourselves on plant health and environmental health.”

Five tips for environmentally friendly gardening

A 100-gallon tea brewer can cost as much as $4,000. A 30-gallon system from SoilSoup, Inc., in Edmonds goes for about $500, still a significant expense for many homeowners. But a more environmentally friendly approach to home gardening can be downright dirt-cheap. Consider these tips from UW gardener Liesl Zappler: