Flower · Asteraceae
When to sow sunflowers
Direct sow after the frost date. Sunflowers grow too fast to benefit from an early indoor start.
Sow direct
1 week after
Counted from your last spring frost.
Days to maturity
70-100
From sowing to a first picking.
Frost tolerance
Tender
How much cold the plant itself will take.
Those weeks become real dates once you name a place.
Timing, in frost-relative terms
Seed packets rarely give calendar dates, because a date that suits one latitude is wrong at another. They give offsets from the last spring frost instead, and those offsets are what make sunflowers plantable anywhere.
- Sow direct 1 week after the last frost.
- Expect 70–100 days to maturity, counted from sowing.
- Sow again every 14 days for a continuous supply.
Getting the timing right
Sow a short row every two weeks until ten weeks before first frost for continuous cut flowers rather than one brief spectacle.
Frost tolerance
Seedlings are killed by frost. Once flowering, stems tolerate a light autumn frost without damage.
Classified as tender, with damage expected below 0°C (32°F)32°F (0°C).