Description

Growing Sunflowers

Sunflowers thrive when grown from seeds directly sown into the garden after the last frost.

Plant seeds in average soil that receives full sun once all frost danger has passed.
Choose a site with well-drained soil. Since sunflowers face the sun, select an open area in your garden. Taller varieties should be planted at the north end to avoid shading other plants.
Prepare the soil by removing weeds and incorporating organic matter into the top 6-8 inches. Level and smooth the soil surface.
Most plants benefit from organic matter. Compost, rich in nutrients and with an ideal pH level, can be added to the planting area anytime. If compost isn’t available, apply 1-2 inches of organic mulch after planting; it will decompose into compost over time. Conduct a soil test after the growing season to determine necessary amendments for the next year.
Plant seeds ½ inch deep in groups of 2 or 3 seeds, spacing groups 18-24 inches apart depending on the variety.
Lightly firm the soil, water thoroughly, and keep it consistently moist.
Seedlings typically emerge within 7-10 days.
Thin seedlings to one plant per group once they develop two sets of leaves.
Control weeds throughout the growing season. Weeds compete for water, space, and nutrients; manage them by frequent cultivation or mulching to prevent seed germination.
Mulching helps retain soil moisture and regulates soil temperature. Organic mulches like shredded leaves enhance soil quality over time but should be kept away from plant stems to prevent rot.
Keep soil evenly moist but avoid overwatering.
Established sunflowers are drought-tolerant and do not require additional fertilizer unless the soil is deficient. Avoid excessive fertilization.
Monitor for pests and diseases; consult your local Cooperative Extension Service for recommended pest controls.
Some sunflower varieties produce only one bloom. Remove plants after flowering to prevent disease issues the following year.
Edible sunflowers mature approximately 3 months after sowing. Harvest seeds by cutting heads off after stalks dry but before fall or winter rains. Check flower heads for maturity signs like shriveled florets in the center and yellowing backs. Hang heads in a warm, dry, well-ventilated place; cover with cheesecloth, netting, or a paper bag with ventilation holes to protect and collect seeds as they dry.
Shorter sunflower varieties can be grown in containers using commercial potting mix.
Pollenless varieties are excellent choices for cut flowers.