Growing Sunflowers in Zone 3B

Sunflowers are easy, dramatic, and multi-purpose — they attract pollinators, provide seeds, and make great cut flowers.

Zone 3B has a short growing season — start seeds indoors when possible and use season-extending techniques like cold frames and row covers.

Top Growing Tips

• Direct sow after last frost — they grow fast and don’t need a head start
• Tall varieties need wind protection or staking
• Plant in succession for weeks of blooming
• Branching varieties produce many smaller flowers instead of one big head
• Leave seed heads for birds in fall or harvest for roasting

Companion Planting

Good companions: cucumbers, corn, beans, lettuce (shade from tall varieties)

Avoid planting near: potatoes (may inhibit growth), pole beans (compete for light)

Harvest Timeline

Flowering in 55-75 days; seeds ready when back of head turns brown

About Zone 3B

USDA Hardiness Zone 3B has an average last spring frost around May 15 and first fall frost around Sep 15. All planting dates above are calculated from these frost dates. Your specific location may vary — check with your local extension office for the most accurate dates.