Grow dill in moderately rich, well-drained soild in full sun 2 to 3 weeks before the average date of the last frost in early spring. Fresh dill leaves can be harvested as needed once the plant is 8 inches; tall or more, though the leaves will have the best flavor for dry storage right before the flowers open or about 70 days after sowing. If you would like to harvest the dill seeds, collect the flower heads before the dried seeds start falling to the ground (about 90 days after sowing) by placing the plant in a paper bag and hanging it upside down in a warm, dry place. Dill, left to its own devices, will readily reseed itself the following year.