Sow directly in the garden in late spring only after nights stay above 10C. Or, start indoors 2-3 weeks before planting outdoors. Small seedlings transplant best. Outdoors, plant in average, well-drained soil, spacing seeds 4 inches apart. Thin seedlings when they reach 3 inches tall to stand 1 feet apart. Sunflowers tolerate dry conditions, but bloom best when watered regularly throughout the season.