Vegetables & Sustainable
The chief methods of weed control are cultivation, mulching, and hand weeding. Proper cultivation includes scraping the soil surface or very shallow penetration of the soil with a hoe or other suitable tool to cut off and remove small weeds. Deep cultivation can prune crop roots, which can cause loss of yield.
Mulching offers a potentially more efficient means of weed control, and it also serves to conserve soil moisture. Organic mulches, such as weathered sawdust, straw, lawn clippings, or other such materials, should be applied 2 to 4 inches (5 to 10 cm) deep on the soil. These mulches can be tilled under periodically to improve the condition of the soil. Some of these materials will require nitrogen during the decaying process, so apply about 2 pounds (0.90 kg) of fertilizer per 100 square feet (9.3 sq m) to assure that adequate nitrogen is available to the mulch and crops.
Weed-block fabric, newspapers, and other such materials can also serve as mulches. They serve the same functions as organic mulches, but they do not offer the soil conditioning potential of organic mulches. Black plastic can be placed on the soil and properly anchored against wind immediately after the soil is prepared for planting. Transplants can then be set through the plastic by cutting holes just large enough for the plant to fit through.
Weed management in vegetable crops - UC IPM