When to Plant and Harvest Sunflower
Tall, cheerful flowers that produce edible seeds
Pets: Not on the ASPCA list. The ASPCA Sunflower entry is swamp sunflower (Helianthus angustifolius), listed as non-toxic. Common sunflower is not listed by species. Pet-Safe Garden Finder
Best Time and Place to Plant Sunflower
In USDA zone 7, the typical spring window is April 1 to May 20. Cooler zones usually plant later; warmer zones plant earlier.
Plant Sunflower in a spot with 8+ hours of direct sun, soil warmed to 55F to 75F, and enough room for 6 inches between plants and 30 inches between rows.
Related Planting Guides
Planting Windows by Zone
| Zone | Spring | Fall |
|---|---|---|
| Zone 1 | May 20 to June 15 | Spring only |
| Zone 2 | May 10 to June 10 | Spring only |
| Zone 3 | May 1 to June 5 | Spring only |
| Zone 4 | April 20 to June 1 | Spring only |
| Zone 5 | April 15 to May 30 | Spring only |
| Zone 6 | April 10 to May 25 | Spring only |
| Zone 7 | April 1 to May 20 | Spring only |
| Zone 8 | March 20 to May 15 | Spring only |
| Zone 9 | March 10 to May 10 | Spring only |
| Zone 10 | March 1 to May 1 | Spring only |
| Zone 11 | February 15 to April 20 | Spring only |
| Zone 12 | February 1 to April 10 | Spring only |
| Zone 13 | January 15 to March 30 | Spring only |
Spacing and Care
- Planting depth: 1 inches deep
- Spacing: 6 inches apart, 30 inches between rows
- Soil temperature: 55F to 75F
- Sunlight: 8+ hours
- Watering: Water deeply but infrequently once established
- Days to harvest: 80
Fertilization
- Low-nitrogen 5-10-10 synthetic: 3 lbs per 100 sq ft
- Compost organic: 2 inches worked into soil
Companion Plants
- Corn
- Cucumbers
- Squash
Avoid Planting Near
- Potatoes
Check any pair, and see which pairings have research behind them, on the Companion Planting Desk.
Harvest Signs
- Back of flower head turns yellow-brown
- Seeds appear plump and developed
- Petals begin to wilt and fall
- Cover heads with netting to protect from birds
Track picks and rate the season on the Harvest Log.
Major Varieties
- Mammoth Sunflower: Tall single-stem sunflower grown for giant heads, edible seeds, and dramatic garden structure
FAQs
When should I plant Sunflower?
Sunflower planting depends on your USDA hardiness zone. In USDA zone 7, the typical spring window is April 1 to May 20. Cooler zones usually plant later; warmer zones plant earlier.
What is the best time of year to plant Sunflower?
The best time of year to plant Sunflower is when your zone planting window is open and soil temperatures are around 55F to 75F. In USDA zone 7, the typical spring window is April 1 to May 20. Cooler zones usually plant later; warmer zones plant earlier.
Where is the best place to plant Sunflower?
Plant Sunflower in a spot with 8+ hours of direct sun, soil warmed to 55F to 75F, and enough room for 6 inches between plants and 30 inches between rows.
How far apart should I plant Sunflower?
Plant Sunflower about 6 inches apart, with rows around 30 inches apart.
What grows well with Sunflower?
Sunflower is commonly paired with Corn, Cucumbers, Squash.
How long does Sunflower take to grow?
Sunflower is typically ready to harvest in about 80 days under good conditions. Use the harvest signs below rather than the calendar alone.
How do I know when to harvest Sunflower?
Harvest Sunflower when back of flower head turns yellow-brown. Seeds appear plump and developed Petals begin to wilt and fall