Description

Here are the growing guidelines for sunflowers:

Sunflowers are cultivated from seeds directly planted in the garden after the last frost.

Plant seeds in average soil with full sun exposure once all frost risks have passed.
Choose a site with well-drained soil as sunflowers face the sun; ensure they are placed in an open area of the garden. Taller varieties should be planted at the north end to prevent shading other plants.
Prepare the soil by removing weeds and incorporating organic matter into the top 6-8 inches; then level and smooth the soil.
Most plants benefit from organic matter in the soil. Compost is ideal, providing nutrients and balancing pH. It can be added at any time. If compost isn’t available, top-dress the soil with 1-2 inches of organic mulch after planting; this will gradually break down into compost. Conduct a soil test after the growing season to determine necessary amendments for the next year.
Sow seeds ½ inch deep in groups of 2 or 3, spacing them 18-24 inches apart depending on the variety.
Gently firm the soil, water thoroughly, and maintain even moisture.
Seedlings typically emerge within 7-10 days. Thin to one plant per group when seedlings have two sets of leaves.
Control weeds throughout the season; they compete for water, space, and nutrients. Cultivate regularly or use mulch to prevent weed seeds from sprouting.
Mulches also help retain soil moisture and maintain consistent soil temperatures. Organic mulches like shredded leaves improve soil over time and should be kept away from plant stems to prevent potential rot.
Keep soil evenly moist but not saturated.
Established sunflowers are drought-tolerant and require no additional fertilizer unless the soil is poor; avoid over-fertilization.
Monitor for pests and diseases; consult your local Cooperative Extension Service for recommended controls.
Some varieties produce only one bloom; remove spent flowers to promote continuous blooming.
Remove plants after frost kills them in fall to prevent disease the following year.
Edible sunflowers mature in about 3 months after sowing. To harvest seeds, cut heads off when stalks are dry but before fall or winter rains. Check for maturity by observing shrunken florets in the center and yellowing backs of flower heads. Cut heads with a foot of stalk attached. Hang in a warm, dry, well-ventilated area to ripen and dry seeds fully. Use cheesecloth, netting, or a ventilated paper bag to protect and collect seeds.
Shorter varieties are suitable for containers; use commercial potting mix for best results.
Pollenless varieties are excellent choices for cut flower arrangements.