Wayne McLaurin has three words for gardeners fighting weeds: "Mulch, mulch, mulch!"

McLaurin, professor of horticulture with the University of Georgia College of Agricultural and Environmental Sciences, said the best way to fight weeds is to start early in the season.

"Once the weeds come up," he said, "you're behind the game. If you start with a clean garden, it's easier to keep them down."

Weeds take up and use water and nutrients more efficiently than many garden plants. "So if the weeds are flourishing," McLaurin said, "They're doing so at your vegetables' expense."

McLaurin tells gardeners to put down mulch as soon as the soil warms up. "If you touch the soil and it feels cool, it's too early," he said. "As soon as the soil feels warm to your palm, mulch it."

McLaurin said mulches act as a barrier to weeds, heat and moisture. "They keep the weeds down, the heat out and the moisture in," he said.

Using waste from around your home as mulch also keeps it out of the landfill. Good mulches include newspapers, grass clippings, ground-up yard waste (small limbs, leaves, needles or bark) and even carpet scraps.

And McLaurin said the more varied the size of the pieces, the better. "A good mix of mulch allows good air flow around the plant roots," he said.

Apply 2 to 3 inches of mulch around the plants. But keep it 3 to 4 inches away from all plant stems. "As much as mulch helps plants, it can also create a problem," he said.

Mulch right against a plant stem can encourage a damp place where disease organisms can grow. The plant could also grow roots in the mulch, and when the mulch dries out, it can kill the roots.

If you want a "prettier" mulch, add a thin top layer of pine straw.

But if you don't want to mulch, use other ways to control weeds in your garden. A hoe works well, McLaurin said, if you use it carefully.

"You have to be careful to not chop up the plant roots along with the weeds," he said. Many plant roots are in the top 2 inches of soil and are easily damaged. "So just scrape with the hoe to kill weeds. Don't chop at them."

And if you choose to use chemical herbicides, McLaurin said, read the label carefully. "Very few herbicides are legal to use on vegetables," he said. "And remember, vegetables are either broadleaf plants or grasses, and that's what herbicides kill. So you have to be careful when using herbicides anywhere near your garden."

The old saying is that if one year's plants go to seed, you'll have seven years of weeds. And that's about right, McLaurin said. Every time you turn the soil, new seeds will turn up and grow -- and take the water and nutrients you put down for your tomatoes.

"If you start by controlling the weeds," he said, "they won't control you later in the season."