Cover crops can be useful tools to improve nutrient management and protect air, soil, and water quality. However, when using cover crops, producers need to determine the type of cover crop and details about the cover crop management to optimize use for site-specific conditions of soil and climate. There is a need to use the right cover crop or cover crop mixture, select the right time to plant and harvest (or kill) the cover crop, and apply the right cover crop management practices at the right location, to increase the benefits of cover crops (the 4Rs for cover crops).