Thumb not green enough for organic gardening? Challenge that thought. Not only is gardening without chemicals healthier for your family, your pets, and nearby ecosystems, but it isn't as complicated as it may seem, say the experts. It's all about smart preparation, says Vinnie Drzewucki, a horticulturist at Hick's Nurseries in Westbury, New York, and author of Flowerbeds and Borders in Deer Country (Brick Tower Press, 2005). "Your first job is to grow the healthiest plants possible. Learn how to do that, and you'll prevent a lot of problems down the line, such as insects, diseases, and poor yields," says Drzewucki. Here's how.

Know thy soil. Is it sandy, loamy, heavy with clay? And perhaps most important, what is your soil's pH level? Most vegetables and annuals prefer a pH level between 6 and 7. Anything above or below will limit the plant's ability to utilize nutrients, says Drzewucki. A good pH test kit costs about $15 at garden centers. After analyzing the soil's texture and testing for pH level, ask your local garden center to recommend the right organic soil amendments and incorporate these before planting. "Doing this can cut down on the need for synthetic fertilizers and pesticides later," says Drzewucki.

Use organic compost and worm castings. Instead of turning to chemical fertilizers, keep soil fertile and plants happy by adding organic compost or worm castings before planting and then periodically throughout the growing season. Compost and worm castings can be found at many garden centers; if you're more ambitious, you can learn to make your own. Compost significantly boosts the soil's nutrients, says Drzewucki, as do worm castings, says Steve Hofvendahl, nursery manager and fruit tree program coordinator at TreePeople in Beverly Hills, California.

Select plants wisely. "Go native," advises Hofvendahl. Plants that match the conditions in your region will more likely thrive. For natural pest control, ask your local garden center to recommend climate-appropriate plants that attract beneficial insects like ladybugs and ground beetles, he suggests.

Mulch. Mulching prevents weeds and disease, helps the soil retain moisture, and replenishes beneficial nutrients as the mulch breaks down, says Hofvendahl. For best results, Drzewucki says, remove existing weeds and put down a 3- to 4-inch layer of organic mulch—wood chips, bark, straw, or even leaves—just after planting.

Find nontoxic solutions. If you do have a diseased or insect-ridden plant, rest assured, "there are nonchemical solutions to every problem," says Drzewucki. For example, gardeners have used oils and soaps for hundreds of years to control insects. (For details, see the Pesticide Action Network North America's alternatives to conventional pesticides at www.panna.org/resources/advisor.dv.html.) And don't be afraid to remove an infected plant, he says. "Look at it as an opportunity to plant something that will do much better in your garden."