Make Your Garden Less Inviting to Pests

By Ann Whitman, Suzanne DeJohn, and The National Gardening Association from Organic Gardening For Dummies, 2nd Edition

Organic gardening helps you make your garden less inviting to pests. Most pests are opportunists that take advantage of weak or stressed plants and take up residence where the eating is easy. Here are some simple strategies that will reduce the vulnerability of your garden plants:

Put plants in the right place: Choose the best location for each plant, taking into account its particular needs for water, sunlight, and nutrients. Plants emit a chemical signal when they are weakened, and pests get the message loud and clear.
Confuse pests with mixed plantings: Insects have chemical receptors that help them zero in on their favorite foods, making your 50-foot row of squash plants look like a giant billboard flashing the message "Squash plants here; come and get 'em!" So plant smaller patches of each crop and scatter the patches throughout the garden or yard.
Keep time on your side: Young plants, with their tender, succulent stems, are easy prey for pests. As plants mature, their tissues become more fibrous and less prone to damage. Use this to your advantage: Plant a crop so that it's growing strong by the time the predominant pest insect hatches.
Avoid opening wounds: Damaged bark or foliage provides an ideal entry point for diseases and insects. Even torn leaves caused by a thunderstorm provide an opening for invasion. Protect plants from mechanical damage caused by string trimmers and rotary tillers. Make sure that mower blades are sharp so that they make straight, clean cuts, rather than leaving ragged edges on grass blades.
Rotate crops: Moving each crop to a new location every year can help foil pests. At the end of the season, many insects leave eggs or pupae in the soil near their favorite host plants. Crop rotation is easy with annual flowers and vegetables that you replant each year.
Don't overfertilize: Excess nutrients are as harmful to plants as nutrient deficiency is. Excess nitrogen, for example, causes stems and leaves to grow rapidly, producing juicy growth that's a delicacy for aphids and spider mites because it's easy to puncture and consume. An imbalance of phosphorus encourages egg production in spider mites.
Clean up debris: Fallen leaves, dropped fruit, and other debris can harbor insects and diseases. Pick up fallen fruit and turn plant residues into the soil or add them to your compost pile. Dispose of diseased plants in the trash or add them to a compost pile that reaches 160 degrees F. Cultivate the soil to work in any debris that could shelter insects through the winter. Cultivating also exposes hiding pests to cold temperatures and predators.
Invite beneficial organisms: Spiders, birds, toads, and a whole host of insects prey on garden pests. Make your garden and landscape an attractive place for them, and they'll do much of your pest-control work for you.