Guru busts organic myths

Jeff Gillman, an associate horticulture professor at the University of Minnesota, caused a stir when he debunked some long-held, much-loved garden myths in his 2006 book, "The Truth About Garden Remedies."

In his new book, "The Truth About Organic Gardening," Gillman takes a hard look at some products and practices we consider organic -- from companion planting (which he considers a smart practice) to using manure to amend the soil.

Q Why did you write this book?

A I was personally concerned about some of the pesticides being used by back-yard gardeners. One of the most dangerous pesticides -- rotenone -- is organic.

Q If it's potentially unsafe, how could it be organic?

A Organic doesn't mean what people think it does. It doesn't mean pure or even pesticide-free. Hey, rattlesnake venom is organic. That doesn't mean it's safe to use.

Q Did you uncover other organic practices or products that concern you?

Q How did you research this book?

A For my book on garden myths, I did a lot of what I call "flyswatter research." I actually tested eggshells to see if they repelled slugs. (They didn't.) I added beer to my hydroponic tomatoes to see if they grew better. (They didn't.)

For this book, I distilled scientific literature. I didn't inject a rat with rotenone for several years to see if it developed Parkinson's. Someone has already done that.

Q Were you able to find solid research?

A The research is solid, but there are fewer studies on organic pesticides than on synthetics. Boy, on Roundup I could find all kinds of stuff - epidemiological studies, toxicology studies. But when I looked at pyrethrum [an organic pesticide derived from chrysanthemums], I had a harder time finding research.

A People tend to over-fertilize, over-medicate and over-water their gardens. And they're obsessed with the idea of a dandelion-free yard.

Q What should we do to battle bugs or diseases?

A Most back-yard gardeners are best off ignoring their pest problems or using a blast of water to get rid of them. They're really not going to do that much damage.

For diseases, the best way to go is to remove the diseased material from the garden as quickly as you can. If you're the type that simply has to do something, use a sulfur spray. Beyond that, you have to ask yourself serious questions about whether a product is safe to use.

Q Are you an organic gardener?

A After your first book, you got an earful. Are you worried about a backlash from the organic gardening community?

Q My biggest fear is that I'll get an anti-organic label. But what I want is for people to be aware of what they're doing and to do the safest thing for themselves and their gardens.

Connie Nelson • 612-673-7087