Parsing the Hope and Hype of Organics

Jeff Gillman's new book is an impartial look at organic vs. synthetic gardening practices. (Chad Gidlin)

Neem oil is derived from a South American tree species. You pour a small amount of it into a gallon or two of water -- the liquid turns milky and smells a little acrid -- and you spray plants that are being attacked by such things as aphids, leaf hoppers and mites. It also doubles as a fungicide. It seems like the perfect alternative to synthetic and toxic rose sprays, for example. Gillman's verdict: effective as an insecticide, less so as a fungicide, and destructive to aquatic life. In addition, it has been linked to reproductive defects in rats and, if not processed correctly, may contain a carcinogen called aflatoxin. For those reasons, he writes, he is "somewhat hesitant about using it."

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In an interview, Gillman tells of coming across a woman with severe circulatory disorders in her hands. She was grossly overdosing indoor plants with neem oil, and he suspected a link. "Generally it's safe," he says. "But [as] with any pesticide, applying it again and again can have terrible effects on the human body."

Organic gardeners rail against synthetic fertilizers for the destructive effect of their salts on beneficial soil creatures and soil structure. Gillman says the only real problem occurs if the synthetics are applied too frequently. "For a garden [as opposed to a farm], I would rather use organic fertilizers, but if you're using synthetics once or twice a year, that's fine," he says. Four or five applications, however, would be "nuts."

One of the hottest things in organic gardening is compost tea, a soup you make by percolating water through a sock filled with natural nutrients and compost. The resulting liquid is teeming with beneficial bacteria and fungi that are then sprayed on plants to feed and protect them. Gillman says the soil is already full of such microbes. The apparent vigor of plants sprayed with compost tea is simply a response to the nutrients taken up by the leaves. There is also a risk of brewing dangerous E. coli germs. And given the time and labor involved, Gillman says, the gardener is better off making a basic foliar spray. You could use liquefied seaweed, for example.

His book touches briefly on lawn and yard care services, and after talking to him at more length, I wished he had devoted a whole chapter to them, given how popular they have become.

"I don't like yard care companies in general," he says. "They use too many chemicals too often." He urges consumers who use them to know exactly what is being applied and for what purpose, and to veto specific applications if necessary: "What's wrong with having a few dandelions in your yard?"

Gillman writes that by presenting various practices and chemicals in an objective light, he hopes he can help readers make up their own minds "without the extreme biases" on either side of the issue. Working against that result, perhaps, is the belief that organic gardening is a holistic enterprise in which you don't cross back and forth across the line of dogma. "I don't know whether it will change people's minds," he says. "I want the book to, at least, start the conversation."