Winter rye (Secale cereale L.) is the predominant cover crop being planted by corn and soybean farmers in the upper Midwest. Winter rye is an excellent nitrogen scavenger, grows at a lower base temperature than most other potential cover crops, is very winter hardy, accumulates high levels of residue, and decreases soil erosion. In recent years, cover crop companies and different interest groups have been promoting the benefits of cover crop mixes and new cover crop species. Our study was designed to test new cover crop options and cover crop mixes for their performance in corn-soybean systems in the upper Midwest. Our objectives were to evaluate potential cover crops and cover crop mixes and their effects on 1) cover crop biomass; 2) weed community; 3) soil, water,and nutrient contents; and 4) corn health and yield.