Description

Growing Guidelines

Sunflowers are best grown from seeds directly sown in the garden after the threat of frost has passed.

Plant seeds in average soil with full sun exposure once all risk of frost has subsided.
Choose a site with well-drained soil as sunflowers thrive in open areas and face towards the sun. Taller varieties should be planted at the north end of your garden 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 afterward.
Organic matter like compost is beneficial for sunflowers, providing essential nutrients and maintaining an ideal pH level. 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 season.
Sow seeds ½ inch deep in groups of 2 or 3 seeds, spacing them 18-24 inches apart based on the variety.
Lightly firm the soil, water thoroughly, and ensure even moisture.
Seedlings typically emerge within 7-10 days. Once seedlings have two sets of leaves, thin them to one plant per group.
Control weeds throughout the growing season as they compete with sunflowers for water, space, and nutrients. Cultivate regularly or use mulch to prevent weed seeds from germinating.
Organic mulches such as shredded leaves not only retain soil moisture but also help maintain consistent soil temperatures. Ensure mulch is kept away from plant stems to prevent potential rot.
Maintain evenly moist soil conditions without overwatering.
Established sunflowers can withstand drought conditions.
Avoid over-fertilizing unless the soil is poor; sunflowers generally do not require additional fertilizer.
Monitor for pests and diseases; consult your local Cooperative Extension Service for recommended pest controls.
Some sunflower varieties produce only one bloom; remove spent blooms to encourage continuous flowering.
Remove plants after they are killed by frost in fall to prevent disease issues the following year.
Edible sunflowers typically mature within 3 months after sowing. Harvest seeds by cutting heads off when stalks are dry but before fall or winter rains begin. Ensure flower heads show signs of maturity such as shriveled florets in the center and yellowing backs. Hang heads in a warm, dry, well-ventilated area to allow seeds to fully ripen and dry. Use cheesecloth, netting, or a paper bag with ventilation holes to protect and collect seeds that may drop during drying.
Shorter sunflower varieties are suitable for container gardening; use a commercial potting mix for optimal growth.
Pollenless sunflower varieties are excellent choices for cut flower arrangements.