Nematodes are very small, unsegmented round worms. Many of them are beneficial, but some damage the root systems of plants by feeding on them. No effective insecticides can be used in small gardens to get rid of these pests. The solarization method, however, focuses the warmth of the sun on the soil. As the soil heats over a period of weeks, the nematodes are killed. An added benefit is that this method will also eliminate weeds and other pests.
Break up clods of earth with a hoe or tiller in the area you're treating for nematodes well in advance of the time you intend to plant. Rake out clumps, sticks and other debris.
Moisten the area with a garden hose. Do not soak it.
Cover the area with a sheet of clear plastic. Tuck the edges of the plastic into the soil and secure them with stakes.
Drape another sheet of plastic over the first. The stakes should hold the plastic a few inches above the first sheet. Make sure the edges of the second sheet reach the ground, and secure them with additional stakes.
Leave the clear plastic on the soil for at least four weeks or as long as six weeks.
Remove the plastic sheeting just before you plant.