These procedures give immediate results, are chemically safe and require little, if any, specialized equipment. Their main disadvantage is that they work only on growing weeds and may need to be repeated frequently. Remove weeds while they are small because it is quicker, easier and does less damage to crop plants. The deeper the soil is disturbed, the more weed seed will be brought to the surface where it will grow. Weed seed may survive many, many years in the soil.
Gardeners often quit weeding as a crop matures.
Weeds do not affect crop yields as much at this stage, but they will produce seed. A single weed of some species can produce hundreds of thousands of seed. Weed removal should continue until the vegetable crop is completely harvested. Gardens may then be kept tilled, mowed or heavily mulched while cops are not growing to prevent weeds from propagating. Frequent tillage has the additional advantages of turning organic material under where it will add to soil organic matter and mechanically destroying any insects present.