Start by removing any visible weeds from the vegetable garden. When possible, pull them up by their roots to ensure that they do not grow back.
Clear away other unwanted items from your vegetable garden, such as rocks, trash or large clumps of dirt.
Dampen the topsoil of your garden by using a hose to spray it lightly with water. The goal is to moisten the top 12 inches or so of soil.
Place a clear plastic sheet over the entire length and width of the vegetable garden. Ensure that the edges do not move by placing heavy rocks, bricks or other items on the corners and sides of the plastic sheet.
Allow the plastic sheet to stay in place for approximately four to six weeks. During this time, the sun will heat the soil, killing any weeds that may be growing underneath.