Technical Abstract: The seed bank in pasture soils sometimes contributes useful plant species after a disturbance; however, it is often a reservoir of weedy plants. Knowledge of how land-use history affects the seed bank in pastures would be useful in anticipating potential weed management needs. We characterized the seed bank in pastures and hayfields with different management histories at the University of New Hampshire Organic Dairy. Three hay fields [two alfalfa (Medicago sativa L.) and one grass] and five pastures (3 to 50 years old) were sampled in August 2007. At each site, two soil cores (1.88 cm diameter by 5 cm deep) were taken at 27 georeferenced points within a 20- by 50-m Whitaker plot. Soil samples were placed in a greenhouse under natural light and controlled temperature for 5 months and germinated seedlings counted regularly. Seed banks in the hay fields had the fewest seeds (8 to 83 seeds per plot sample) and plant species (2 to 14 per plot sample) compared with pastures. Old permanent pastures had 98 to 277 seeds per plot sample and 12 to 25 plant species. Nearly 42% of the soil samples from the hay fields had no germinable seeds, whereas only 7% of soil samples from pastures had no germinable seeds. Agrostis spp. and Festuca rubra L. were most abundant seeds in the pastures and grass hayfield. Ambrosia artemisifolia L. and Juncus tenuis L. predominated in the alfalfa fields. Few noxious weed seeds were present in the soil. Further monitoring will examine how management alters the seed bank and vegetation.