Suitable cover crop species and reliable establishment methods need to be assessed to identify viable cover cropping strategies that provide environmental benefits while maintaining productivity in corn-soybean rotations. Successful establishment of cover crops depends on both the timing and method of planting. Cover crops interseeded prior to closure of the primary crop canopy must be planted early enough to establish roots while sufficient solar radiation is reaching the soil surface, yet late enough to avoid direct competition with the primary crop for water, nutrients, and solar radiation. The objectives were to gauge establishment of a range of cover crop species and planting methods, and to determine whether successfully interseeding cover crops into corn can provide ecological benefits through utilization of excess N and water without reducing cash crop yields.