Weeds are opportunists. Give them an inch and they take over the whole yard or garden. Like the old door-to-door salesmen, it's much easier to keep them from getting a foot in the door than to get rid of them once they're settled in. We have plenty of ideas to help you get rid of weeds. But first, here are a few tips to keep them from ever setting root in your landscape.

• Keep the grass on your lawn as thick and healthy as possible. A lush, thick lawn leaves no gaps for weeds to fill and effectively cuts off the light they need for germination. Certain turfgrasses, such as zoysia and bermudagrass, can crowd out weeds altogether with their dense, invasive growth.
• Seed or sod any bare spots as soon as possible. Never leave freshly cultivated soil vacant for long. If you're starting a new lawn from bare soil or establishing a flower bed or garden, be ready to plant or sow seed as soon as possible after tilling.
• Plant gardens and flower beds densely and mulch between plants. Choose plants that produce abundant foliage; plant them close together; and spread organic mulch around the plants.
• If you are sowing annuals from seed, seed liberally and plan on thinning the flower bed later.
• Eliminate emerging weeds before they have a chance to flower and set seed. Perennials that spread underground (such as tall nettles) should be pulled or treated the moment you see them, annuals and seed-bearing perennials such as dandelions  just as they begin to flower. For control and prevention, spring and fall are the key times to treat your lawn with an effective broadleaf herbicide. The spring treatment will kill this year's broadleaf weed crop, while the fall treatment will help prevent stubborn perennials from returning next year.
• Don't plant seeds too early. The seeds will either fail to germinate or take a long while to sprout. In the meantime, weeds better adapted to cool ground temperatures will rush to fill the void.
• Spread mulch around the base of trees and in the open spaces between plants and shrubs in landscaped areas.