Testing old gardener's tales

"The Truth About Garden Remedies: What Works, What Doesn't & Why"
By Jeff Gillman
Timber Press, 2006, $19.95

When I first worked at the University of Washington's Center for Urban Horticulture 20 years ago, a goal of the new institution was to shed scientific light on garden myths.

Jeff Gillman, a professor of horticultural science at the University of Minnesota, has pretty much the same mission in his "The Truth About Garden Remedies." He turns his well-trained eye on a surprising variety of practices long passed down from one gardener to another.

It's not that Gillman is against household remedies or home-brewed tonics, it's just that he wants to understand if they work and, if so, why and how. This man doesn't like the unexplained, mysterious, or whimsical.

This book is the result of years of research into what really does and does not encourage plants to grow faster and what works to protect them from diseases and pests. Gillman is also very clear on what concoctions should be avoided.

Does music make plants grow more luxuriantly? Should you plant trees deeply so roots won't dry out? Do coffee grounds change soil pH?

Probably not, absolutely not, and not really.

Plants are subject to all kinds of noise, including human chatter and music, and Gillman sees little proof that any of it makes much difference, although music and conversation, even one-sided, may well be therapeutic for the gardener.

Planting deeply is more likely to smother or drown the tree than to help it, and other soil acidifiers are more effective than coffee. As coffee breaks down, though, it does provide nutrients that benefit some plants (lettuce) while harming others (tomatoes).

So be prepared to have some of your long-cherished gardening notions debunked. But you'll also learn how to spend your gardening time and money.

A warning: Compost-tea advocates won't like Gillman's conclusions. But he does advocate a saucer of beer for slug control and advises that homemade deer and rodent repellents are as effective as commercial ones.

Valerie Easton also writes about Plant Life in Sunday's Pacific Northwest Magazine. Write to her at P.O. Box 70, Seattle, WA 98111 or e-mail planttalk@seattletimes.com with your questions. Sorry, no personal replies.