Herbicide-resistant weeds are becoming a more and more common problem for farmers growing grain and vegetable crops. As a result, the farmers are looking for alternatives to herbicides to control weeds. One promising approach is the use of cover crops, which are planted in the off season to protect the soil. Thick cover crop growth can often compete well with weeds during the cover crop growth period, and can prevent most germinated weed seeds from completing their life cycle and reproducing.