Weed management is often the most limiting factor in organic grain production. Producers in the Upper Midwest either include a wheat/red clover phase to help suppress weeds or a multiyear forage phase in the rotation. In this study, the weed seed bank was monitored since 1992 in two chemical-free, three-year rotations: 1) Organic Grain (OG, corn-soybean/wheat-wheat/red clover); and, 2) Organic Forage (OF, oats/peas/alfalfa-alfalfa-corn). Soil samples were taken in the spring in all plots with corn the previous year in March of 2004 and 2005 and seedlings were counted and identified as they germinated in the greenhouse. (2005 data will be completed in late August). Weed seed density from the 2004 samples remained high in the Organic Grain rotation (9,300 seeds/mē ), while in the Organic Forage rotation, weed seed numbers were lower (3,000 seeds/mē) and actually nearly equivalent to the no-till corn-soybean system (2,400 seeds/mē). The weed community also shifted in both rotations. In the OG rotation rotary hoeing, cultivation and a single season of wheat and frost seeded red clover were not particularly effective against grasses (especially foxtail). Grass weed seed populations increased over five fold to dominate the community (80% grasses). In the OF rotation grass seeds did not increase, and broadleaves remained the predominate group in the seed bank. These results suggest that if farmers can find a market for the forage they produce, it would be advantageous to expand grain rotations to include a full one- or two-year forage phase.