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In the Garden

Ditch the sprays


I READ A LETTER IN AN ADVICE COLUMN this weekend from a mail carrier. He was complaining about the presence of spiders in mailboxes along his rural route. His plea to the public was something along the lines of, "I know people regularly spray their homes and gardens for insects, but please remind your readers to spray the inside of their mailboxes, too."

His vision of responsible homeowners dutifully dousing their kitchens and lawns with pesticides left me a little stunned. I put my paper down and watched the trail of black ants marching across the kitchen table toward my toast. All right, maybe I'm a little more tolerant of bugs than most people. Still, I could not imagine my garden without its population of butterflies, bees, spiders and beetles. What is the point of planting something as alive, as diverse, as a garden, then banishing its six- and eight-legged inhabitants?photo of a bug

Concern over pesticides seems so widespread that it's hard for me to imagine that many Humboldt County residents routinely spray their home and garden anyway. The bad news about pesticides and herbicides is becoming common knowledge: The EPA is studying the potential effects of chemicals on the human endocrine system, and warns about the risk of pesticide drift into neighboring areas or contamination of drinking wells. The agency has stated that children are at particular risk of harm from pesticide exposure and now promotes lower-risk pesticides and organic pest control methods like integrated pest management, in which farmers use minimal chemicals and instead focus on techniques like crop rotation and releases of beneficial insects. In other words, organic approaches are going mainstream.

You can use the same techniques at home. Here are some suggestions for keeping chemicals out of your garden:

Maintain a balance of beneficial insects. Ladybugs aren't the only good bugs out there. Their larvae devour aphids, but there are plenty of other bugs that also do the job. Green lacewings, damsel bugs, beetles, wasps, and other insects can help keep an overpopulation of "bad" bugs in check. The trick is to plant what they like. Many beneficial insects are attracted to plants with tiny flowers, so try yarrow, alyssum, and tansy. Let a few herbs go to seed -- cilantro, dill, fennel, and carrots all lure beneficials. Then be prepared to put up with a little damage from the bad bugs -- after all, the point is to reach a balance and provide a small, but sustained, food source so that beneficials will stay around.

Use traps and lures. Most nurseries around town sell yellow sticky traps that will lure aphids and whiteflies to their death. Gardens Alive, an online purveyor of environmentally friendly garden products ( or 513-354-1482), sells traps designed to address particular insects, and lures that will attract beneficials. They also sell many of the other products I'll mention in this column, if you can't find them at your favorite nursery.

You can also use particular plants as a trap crop. For instance, plant mustard greens to lure flea beetles away from more valuable crops like cabbage or arugula. Nasturtiums can attract aphids away from roses. Lovage is a herb that tomato hornworms enjoy; plant some near tomato plants to lure the nasty green caterpillars away. Monitor the trap crop closely, and when it's fully infested, rip it out and throw it, and its inhabitants, away.

Enlist microbial creatures. Organic gardeners have learned to use the power of beneficial nematodes to combat soil-dwelling pests. These microscopic creatures exist naturally in your soil, and each species has its favorite food. You can get nematodes to combat cutworms, fleas, and even other nematodes, such as the one that causes root knot in carrots. They come suspended in a solution that is soaked into a sponge: to apply the nematodes, you just drop the sponge in a bucket of water and then spray the nematode-soaked water around the garden. You can even buy beneficial fungi that fight diseases: Gardens Alive's SoilGard contains a fungus that fights other, more destructive fungi to prevent common forms of rot and wilt diseases.

Try natural solutions. You can buy insecticidal soap (look for the Safer brand at nurseries) or mix up dishwashing liquid and water to spray on aphid-infested plants. Soap is very effective against soft-bodied insects but does not harm beetles and other good bugs. A spray made with water, garlic, and chili pepper is also effective against aphids and whitefly. A teaspoon each of baking soda and liquid dish soap, mixed with a quart of water, can help fight fungal infections like blackspot and powdery mildew.

For serious infestations, you can buy dormant oil to smother pests, or spray with rotenone/pyrethrin, a plant extract that targets potato beetles, or Bt, a bacteria that causes caterpillars to stop feeding and die. However, even organic gardeners use these products sparingly and only apply them after they have diagnosed the problem and made sure that the product will work against that particular pest. Knowledge is the organic gardener's best weapon; even a natural pesticide should never be applied in a "broad spectrum" manner that might upset the natural balance of insects in the garden.

Prevent, prevent, prevent. Pick off diseased foliage and throw it away. Use natural solutions early before serious infestations take hold. And use compost, mulch and organic fertilizers to grow strong, healthy plants that can tolerate a little damage. (Recent studies indicate that organically grown crops may be higher in beneficial antioxidants precisely because their natural defense system is used more often to combat minor attacks by pests and diseases.)

Kill weeds the old-fashioned way. There are plenty of natural alternatives to pesticides. The USDA recommends a solution of 5 to 10 percent vinegar mixed with water to kill weeds, and pouring boiling water on weeds growing between cracks in the pavement is another great "home remedy." Smother weeds with mulch and plant perennials close together to crowd out weeds. And if your garden does get overrun, as mine does every year around this time, just remember that pulling weeds is, after all, great exercise and an excuse to spend more time in the garden. And isn't that the whole point?

garden-related announcements and news to Amy Stewart.


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