When weed, disease, or pest problems become bad, it may be time to try to “solarize” your soil.
This means to add a covering of clear plastic to your garden for several weeks. The longer the period of time the plastic stays in place, the better.
By covering the soil in this manner for at least six weeks during the hottest part of the summer, you can trap enough heat from the sun to destroy seeds of weeds. It will also keep soilborne fungal diseases such as verticillium, fusarium, and Southern blight in check for three years and restrain root-knot nematodes for at least 2 years.
Use clear plastic that contains ultraviolet inhibitors, which prevent the plastic from breaking down. A plastic with 2 to 4 mil thickness will be more durable.
Simply rake you garden bed until it is smooth. Then saturate the soil with water for several hours. Lay the plastic over the sight. Stretch it tightly and use rocks or other weights to keep the plastic in place.
Remove the plastic after a minimum of six weeks. Longer is better. Solarizing for an entire season would be most worthwhile.
Wait at least a month after solarizing to plant. Spread compost over the plot and begin planting. If you are going to till the soil, do so shallowly to avoid bringing up weed seeds that may still be viable.