If you've got the perfect area in your yard for a vegetable garden, but it's currently filled with tough lawn grass, you might think you'll never be able to turn it into a viable garden plot. Grass is especially tough to remove, because the roots beneath the surface come right back up through anything you plant. The only way to prepare a garden site is to completely remove any roots or seeds in the soil. Harsh chemicals will finish them off, but you'll have to deal with chemical residue in your edible plants. A safe and effective way to renovate any plot of land into garden space is by sterilizing the soil and killing the plants using the power of the sun. Solar sterilization will take a few months, but in the end you'll have clean soil with no viable seeds or bacteria to bother your growing garden.
Dig up the soil in your garden plot area, removing any grass plants that you can, as well as rocks, sticks and other foreign objects. Dig down to a depth of 8 inches. Rake the surface of the soil so the top is smooth.
Water the entire plot until the soil is very wet and muddy. Let the water soak in for an hour, then water the soil again.
Dig a trench around the outside of the garden plot that measures 3 inches deep and 3 inches wide.
Spread a sheet of clear plastic sheeting over the entire surface of the garden. If you have to use two or more sheets to cover the entire garden, overlap the edges at least 6 inches to make sure all the soil is covered.
Push the edges of the sheeting into the trench. Pull the sheeting tightly enough so that it touches the soil underneath. Hold the sheeting in place by covering the edges with large rocks, old bricks or a thick layer of soil.
Check the plot every few days to make sure the plastic sheeting stays in place and isn't blown around in the wind. Replace and improve any part of the trench system that doesn't hold the plastic in place.
Remove the plastic sheeting after eight weeks. Plant your garden seedlings or seeds, taking care not to disturb the soil beneath the original 8 inches you dug to prevent stray seeds from being pulled up into the sterilized soil.