Sunflower
Helianthus annuus
Sow outdoors 1 week after your last spring frost. Space plants 12 in (30 cm) apart.
Photo: Adarsh Patel, CC BY-SA 4.0 · source
When to plant
Timed from your frost dates, so it holds wherever you garden. Give yours and every step below becomes a date.
Optimal Direct Sow
From seedRecommended- Sow outdoors1 week after your last spring frost
- First harvestabout 85 days after sowing
Optimal Indoor Start
From seed- Start indoors2 weeks before your last spring frost
- Begin hardening offaround your last spring frost
- Plant out1 week after your last spring frost
- First harvestabout 85 days after sowing
Growing sunflower
- Spacing in the row
- 12 in (30 cm)
- Between rows
- 30 in (76 cm)
- Planting depth
- 1 inch
- Sun
- Full Sun
- Soil
- Well-drained, average to rich loam with good organic matter content.
- Germination
- 7-14 days at 65-75°F
- Harvest season
- Late Summer to Early Fall
- Mature height
- 5-10 feet
- Support
- Staking may be required for tall varieties in windy conditions.
- Life cycle
- Annual
Direct sow after the last spring frost when soil temperature consistently reaches 60°F.
Watering. Maintain consistent moisture until established, then tolerate moderate drought. Deep watering is preferred.
Corn
Squash
Pole Bean
Cucumber
PotatoFeeding
- Seedlings
- Generally not required if soil is adequately prepared with compost or balanced amendments.
- Growing
- Apply a balanced fertilizer or one slightly higher in phosphorus and potassium once plants are established.
- Flowering and fruiting
- Continue with a phosphorus/potassium-rich fertilizer to support robust flowering and seed development.
- How often
- At planting, then once before flowering begins.
- Note
- Avoid excessive nitrogen application after initial establishment to promote flower and seed production over lush foliage.
Your sunflower, planned to the day.
Canopy turns these timings into dates from your own frost data, places every plant at its spacing on your garden map, and tracks it all the way to harvest.