Incorporating cover crops into the two-year corn (Zea mays L.)--soybean (Glycine max L.) rotation can reduce soil erosion, increase soil organic matter, improve soil structure, and reduce nitrate (NO^sub 3^) leaching. However, it is often difficult to establish winter cover crops in the cooler climate and shorter growing season of the northern Corn Belt. Miguez and Bollero (2005) reported that grass cover crops in the north central US would only provide marginal benefits due to low biomass production. Through growth simulations, Baker and Griffis (2009) found that the main limitations are degree days and photosynthetically active radiation. Strock et al. (2004) suggested that based on average weather patterns in southwestern Minnesota, winter rye (Secale cereal L.) would only be a successful cover crop in one out of four years. Here, Wilson et al discuss some of the limitations of aerial seeding, future research that is needed to overcome several of the barriers, and alternative cover cropping practices.