Organic farmers in the northern US Great Plains are exploring ways to use cover crops to control weeds and improve soil health without tilling the soil. They are testing different cover crop species and termination methods to find the best way to kill the cover crops early in the season so that cash crops can be planted successfully. Challenges include excessive water use by cover crops, lack of nitrogen supply from legume cover crops, and difficulty in controlling perennial weeds. Despite these obstacles, using killed cover crop mulch can be a helpful tool for organic farmers, along with crop rotation, grazing strategies, and high-residue cultivation equipment. New crop rotation designs may lead to more efficient use of resources and better weed management on organic farms.