Correction to This Article
The Green Scene column misspelled the name of a chemical that is increasingly being replaced by iron phosphate for slug control. It is metaldehyde.
Green Scene

Non-Toxic Alternatives to Keeping Pests Out of the Garden

Compost has a greater impact on plant health than any other single factor.
Compost has a greater impact on plant health than any other single factor.
By Joel M. Lerner
Saturday, March 28, 2009

Pest control doesn't have to be toxic.

Homeowners these days want to preserve their lawns and plantings, but not at the expense of the environment, especially the Chesapeake Bay watershed.

It may take some investigation to find environmentally friendly materials, but if you start early and plan properly, you can have a garden that is pest-free and full of thriving, blooming, buzzing, fluttering life from spring into fall.

There's a rapidly growing list of natural remedies for the garden and landscape -- a fix for everything from poor soil and weeds to insects and disease. Environmentally friendly materials are being developed from seaweed, soap, sand, gravel, garlic, corn, castor beans, canola oil, marigolds, trees, fish, eggs, expanded slate, landscape waste and other substances.

Before you apply any material to the garden, apply common sense to the gardening process. A healthy environment is the best protection your plants can have. Many amazingly simple actions can help your plants fend off pests and diseases.

Start with healthy soil. Good drainage, aeration and nutrients are the goals. Use soil amendments, especially in heavy clay, and consider composting. Compost has a greater impact on plant health than any other factor. It will condition the least hospitable clay soils and help them bind nutrients to deliver them to the plants instead of running off into the Chesapeake Bay. Composting is not difficult, and there are many types of bins and receptacles that make it more convenient. Most garden and home improvement centers sell compost and equipment. Books and Web sites can supply tips on how to make it. One site with excellent information is

Healthy soil is not the only prerequisite for a thriving garden. You need to start with plants that are going to grow in the conditions you have. Think about using more natives, plants that already like the growing conditions in your region. If you live in a dry area, use drought-tolerant perennial species such as gayfeather (Liatris spicata), hyssop (Agastache), lyre-leaf sage (Salvia lyrata) or woody plants such as glossy abelia and boxwood. If you have hot, humid summers, as we do in the Washington area, try perennials that enjoy these conditions such as evergreen wood fern (Dryopteris marginalis) or Louisiana iris and woodies such as swamp azalea and river birch.

Once you have the right plants, you need to place them where they can thrive. A shade-tolerant plant will generally wilt in the sun. Flora thrives when it doesn't have to compete with weeds for water and nutrients. Mulch and landscape fabric can help reduce weed problems. Pull weeds early and often, before they produce seeds.

Keeping the garden clean is another simple way to avoid disease and insect problems. Cut or pull diseased plants and don't put them in your compost. Get rid of debris in the yard, such as old lumber, which can harbor disease or provide havens for pests such as slugs and rodents.

Do research based on last year's gardening experiences and check with your local cooperative extension service on potential diseases and insects that might harm your plants. Then find out what kind of natural resources exist to fight them. Remember that each product should be evaluated on its own merits or dangers. They are chemicals and, in some cases, poisons. Don't use any product universally or haphazardly. Many are effective only at a particular life stage, and some are plant or pest specific.

Here are a few of the natural products on the market. They are available at many garden centers:

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