Black Oil Sunflower Seed
Helianthus annuus • Asteraceae
🌱 Seed Category
Flower
🌍 Origin Region
North America, widely cultivated globally
📅 Days to Maturity
80 to 120 days from planting to seed harvest or flower bloom.
🌡️ Hardiness Zones
USDA Hardiness Zones 2 through 11, grown primarily as a summer annual.
About This Seed
The seed is teardrop-shaped, plump, smooth, and uniformly dark black with a hard hull. The resulting plant is a tall, erect annual with coarse, hairy leaves and large, bright yellow flower heads that track the sun.
Growing Information
Growing Season
Spring and Summer, direct sow after last frost
Germination
Germinates in 7 to 10 days at soil temperatures between 70°F and 85°F. High germination rate, requires no pre-treatment, and can be covered lightly with soil.
Planting Instructions
Plant 1 inch deep, spaced 6 inches apart, with 24 to 30 inches between rows. Prefers well-draining loamy soil with a neutral pH between 6.0 and 7.5.
Sunlight & Water Needs
Requires full sun (6 to 8+ hours daily). Water regularly until established, highly drought-tolerant once mature.
Companion Plants
Beneficial companions include cucumbers, corn, and squash. Avoid planting near potatoes and pole beans.
Special Characteristics
Highly attractive to pollinators, birds, and beneficial insects. Exhibits strong heat tolerance and allelopathic properties that inhibit weed growth.