Early seeding and good weed control are essential. Fertilizers Fertilizers usually are not required. If a soil test indicates a lack of phosphorus, potassium or sulphur a corrective application should be worked into the soil before seeding. Pollination Honey bees are effective, and one to one and one-quarter strong colonies per acre should be provided. Leafcutter bees are also effective pollinators.
Some growers allow the first growth to set seed.
Others get better results by clipping the stand in early to mid-June. This delays flowering and gives time for bee populations to build up. The growing season on the prairies is too short to permit clipping. Insect Control Insect control is rather unusual, but one should follow good field sanitation practices and remove or burn harvest residues. Harvesting Ripe pods pop open and shatter seed when dry.