When planting sunflower seeds, make sure the soil is warm and well-drained, as they thrive in full sun and temperatures above 60 degrees. Sow the seeds about an inch deep and six inches apart, and water them gently but thoroughly. You can also start them indoors in seed trays a few weeks before the last frost, then transplant them outside when they're a few inches tall. Keep the soil consistently moist during the first few weeks after planting, and once they're established, you can reduce watering to about an inch per week.