Sowing: Direct sow in late fall, pressing into the surface of the soil since this plant needs light to germinate. For spring planting, mix the seeds with moist sand and store in the refrigerator for 30 days before planting. Keep the soil lightly moist until germination, which usually takes 14-30 days. The seeds can also be started indoors 6-8 weeks before planting in spring. Keep seedlings lightly moist, and transplant them as soon as they have developed several leaves.