Growing notes
Iowa State Extension ↗Sunflowers prefer fertile, well-drained soils and are quite drought-tolerant once established, but should not experience serious water stress during flowering and seed formation for best seed quality. Avoid high-nitrogen fertilizers as they tend to promote vegetative growth and inhibit flowers.
Harvest signs
Iowa State Extension ↗Seed heads are ready to harvest when they face downward and the inner petals (flowers) can easily be rubbed off. By this time, the outer ring of colorful petals is spent, and the back of the seed head is a lemon-yellow color. Check a few seeds to make sure they are completely filled. Seeds reach maturity 70-100 days after planting.
▶Planting reference— Depth, spacing, pH, light
▶Pests & diseases— stink bugs, aphids, caterpillars, birds, +3 more
Companions & antagonists
Common questions
How much water does sunflower need?
Sunflower has middle-of-the-road water needs. Aim to keep soil moisture around 25–50%, letting the top inch dry slightly between waterings rather than staying soggy.
Can I grow sunflower in a raised bed or container?
Yes — sunflower does well in raised beds and is happy in a decent-sized container too, as long as drainage is good.
Does sunflower come back every year?
No — sunflower is an annual. It completes its life in one season, so you replant it each year.