Chemicals should be a last pest-control resort. Many pesticides are harmful to people, and though they do kill pests, they also kill soil nutrients and beneficial insects. If you must spray something on your plants, start with plain water -- it will kill some insects and force off many others. For a little more power, add an insecticidal soap to the water spray. Insecticidal soaps, made from the fatty acids of animals and plants, are both safe and effective in controlling soft-bodied insects.
Some pairs of plants just seem to grow well together, often because one helps repel pests from the other. Employed by gardeners for centuries, this concept is called companion planting. For example, planting onions or sage near carrots helps repel flies that can infest the carrots. Similarly, radishes planted among cucumbers help ward off cucumber beetles. Garden books can help you find good companions for your favorite plants. Certain plants are natural botanical bodyguards, protecting just about anything nearby. Marigolds, for example, boast a natural resistance to harmful nematodes and an odor that turns off pests large and small. Other pest-repelling plants include garlic, lovage, and catnip.
You don't have to take on garden pests by yourself. Nature provides an army of allies in the form of predators that feed on insects. Your friends include birds, bees, wasps, and spiders, as well as beneficial insects such as ladybugs, green lacewings, predator mites, mealybug destroyers, ground beetles, and the wickedly named assassin bug.
If buddy bugs are in short supply in your garden, you can buy them -- either by mail or from a garden center -- and store them in the refrigerator until you're ready to release them.
A birdbath and feeder will attract feathered predators to your garden, while nectar-producing flowers will draw beneficial insects. Early bloomers such as pansies and Alyssum are good choices, as are lavender, cosmos, coneflowers, and goldenrod.
Still need more ideas and strategies for dealing with your garden pests? Here are some more tips for eradicating unwanted visitors.
- Use old soap bars as a deer deterrent. Save soap remnants from your bathroom or hotel soap from your travels and place them in a pouch made out of pantyhose or cheesecloth. Hang the pouch near trees, shrubs, or other plants you want to protect.
- Spread diatomaceous earth, a dust or powder made from ground-up algae, on the ground around plants as a barrier to crawling pests such as caterpillars, slugs, snails, thrips, and earwigs. The powder's sharp edges kills these creatures. Wood ashes have a similar effect.
- Mix up your own organic sprays and dusts out of hot-to-the-taste or strong-smelling herbs, spices, and other edibles. Gardeners commonly use garlic, parsnip roots, bell peppers, onions, cayenne pepper, and pipe tobacco.
- Try dormant oil sprays as another nontoxic way to kill insect pests. A coating of dormant oil suffocates bugs without harming trees or plants.
- Use wire mesh to keep rabbits out of the garden, creating a barrier that extends at least 2 feet above the ground, plus at least 6 inches under the soil. The openings in the mesh should be no larger than 11 x 2 inches square.