As organic gardening becomes more common, there are many assumptions about its safety that get promoted by the media. It's hard to know which organic gardening techniques and products are effective and safe.
Jeff Gilman, horticulture professor at the University of Minnesota, has researched many of the claims about organic gardening, and he shares his findings in The Truth About Organic Gardening (Timber Press, 2008; $13). Gilman gives a thumbs-up or thumbs-down to many of the practices and products used in soil building and in weed, insect, disease, and animal control. He also includes a chapter on the claims made by the organic food industry.
Some of his findings confirm, and some contradict, conventional knowledge. For example, he found garlic is an effective repellent for a large number of insects. The organic pesticide rotenone is dangerous to beneficial insects, aquatic life, and humans, and is more toxic than many synthetic pesticides. Japanese beetle traps tend to attract more beetles than they trap. He found that a better solution for these beetles is beneficial nematodes, which can kill up to 80 percent of the Japanese beetle larvae in lawns where they are applied.
For more information about The Truth About Organic Gardening, go to: Timber Press