Nothing is more exciting than planting a spring vegetable garden; nothing is more disappointing than having it overrun by weeds.

Although a 2- to 3-inch layer of loose mulch and hoeing are usually sufficient for most vegetable gardens, homeowners with large areas may need the help of herbicides to counter weeds. So, if you dug your way through the crabgrass to find that prize-winning tomato last year, here is what you can do to keep the weeds under control this year.

There is one pre-emergence and one post-emergence herbicide that can be used on home vegetable gardens. The pre-emergence herbicides is trifluralin. Pre-emergence herbicides kill weed seeds as they germinate. They usually have no effect on weeds that have emerged. So they must be applied either before weeds come up in the spring or after weeds have been physically removed. The pre-emergence herbicide trifluralin is sold under the trade names of Treflan, Preen, Miracle-Gro Garden Weed Preventer and Monterey Vegetable and Ornamental Weeder.

The post-emergence herbicide is sethoxydim. This product will only kill grasses; broadleaves are not affected. However, it can be sprayed directly over the top of many vegetables. Sethoxydim is sold as Poast, Monterey Grass Getter and Hi-Yield Grass Killer.