Sow seeds directly in the garden in spring in well-worked, fertile soil. Space seeds 1/2″ deep and 2″ apart in rows 18″ apart. Thin seedlings, when large enough to handle, to a final spacing of 12-18″ apart so these vase-shaped plants have room to grow. Begin harvesting when plants have 6-8 stalks by snipping off outer stalks at plant base. New leaves grow back for a contiguous supply.