Botanical Name: Helianthus annuus
Native: North America
Plant Dimensions: 6'–10' tall
Variety Information: Up to 12"-wide flower with yellow petals and a brown center. Single type.
Exposure: Full sun
Bloom Period: Summer to frost
Attributes: Attracts Pollinators, Cut Flower, Drought Tolerant, Heat Tolerant
When to Sow Outside: RECOMMENDED. 1 to 2 weeks after your average last frost date.
When to Start Inside: 2 to 4 weeks before your average last frost date. Sunflowers are senstive to root disturbance; sow in biodegradable pots that can be planted directly in the ground.
Days to Emerge: 10–15 days
Seed Depth: ¼"–½"
Seed Spacing: A group of 3 seeds every 24"
Thinning: When 3" tall, thin to 1 every 24"
Harvesting: Seeds are ready to harvest when the back of the head has dried and turned brown, about 4 weeks after the flowers have been pollinated. Petals will have wilted and fallen off, and the seeds will be plump, and colored white with gray/black stripes. Seeds ripen around the outside of the flower first; the ones in the center will ripen last. Average yield is approximately 1 pound per head.
Mammoth Russian Sunflower Seeds Reviews