Abstract: Wildflower crops to produce biomass suitable to feed biogas plants are promoted in Germany. Flowering plants produce seeds. These seeds from wildflower crops can add to the seed bank, but can also be a food resource for seed predators. We examine the seed shed of wildflower crops and weeds in three field experiments in North-Eastern Germany. Seed traps were installed and emptied monthly. Seeds were counted species specific. Over the sites and throughout the time more weed species shed seeds into the traps than species of the wildflower crop. All three sites show that more seeds of the wildflower crop correlated negatively with weed seeds. Peak of seed shed was August for wildflower crops and weeds.