Parsing the Hope and Hype of Organics

Jeff Gillman's new book is an impartial look at organic vs. synthetic gardening practices.
Jeff Gillman's new book is an impartial look at organic vs. synthetic gardening practices. (Chad Gidlin)
By Adrian Higgins
Thursday, February 21, 2008

Imagine a political debate in which a moderator could take apart the campaign promises and reveal, with Solomonic wisdom, their true benefits, drawbacks and costs.

Enter Jeff Gillman, a professor of horticulture, who is passing judgment not on the current presidential race but on an even longer-running contest: the pros and cons of organic vs. chemical gardening.

Gillman has spent years poring over scientific data to scrutinize the claims of the organic gardening movement in an attempt to give objective assessments of hundreds of products and practices.

This is not ivory tower stuff; all gardeners are faced with this vexing choice. Plants need feeding; plants get sick or eaten.

Anyone who has haunted garden centers and mass merchandisers for many years, as I have, can see that there has been a profound shift in consumer demand away from the stinky chemical herbicides and pesticides that once monopolized the shelves and toward organic controls, fertilizers and soil mixes.

Trying to find definitive, impartial advice is hard. At its extreme, organic gardening isn't so much a practice as a religion, whose true believers view chemicals (and the people who make them) as devilish and assert that natural controls will keep plants healthy and the environment -- including you -- safe. On the other side, advocates point out that chemical, or more correctly, synthetic fertilizers and pesticides are as safe as they are effective.

Confusing the issue is the fact that eco-friendly claims are a huge part of every sales pitch these days. How do you separate the hype from the facts? Spending 13 bucks on Gillman's new book, "The Truth About Organic Gardening" (Timber Press), may go a long way.

But before we get into some of his findings, we need to take a step back. Gillman's fundamental argument -- to which I subscribe wholeheartedly -- is that if you are simply replacing synthetic products with organic ones, you are missing the point. The aim is to reduce the need for fertilizers and, especially, pesticides. How do you do that?

You build the soil with correct amounts of compost and mulch, choose plants that do well and place them in their optimum locations. "These are the true parts of organic gardening," says Gillman, a professor of horticultural science at the University of Minnesota.

Even seemingly tiny measures can make a big difference. I know that I can use a garden hose to wash the aphids from my roses, but know too that if I do that when I return from work instead of before leaving, I will increase the risk of the roses' getting black spot disease.

In writing the book, Gillman says, he wanted to point out something that is probably not well understood: that organic products can be as harmful as synthetics, or even more so.

Rotenone is an organic dust that gardeners place on potato plants, for example, to kill the destructive Colorado beetle. The plant-derived insecticide is highly toxic to aquatic life, and when low doses were injected into rats, they caused symptoms similar to those of Parkinson's disease. "Why would any sane person use this pesticide?" Gillman writes.

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