When to plant sunflowers

Planting dates for sunflowers at your ZIP code, from local frost records and extension advice.

Frost risk you'll accept

Historical frost averages plus extension guidance, not a forecast. Check the forecast and soil temperature before planting.

Sow sunflower seeds outdoors from your last spring frost date to about 4 weeks after it, once the soil has warmed to at least 50°F. Sow a few more every 2–3 weeks until midsummer for a longer run of flowers.

Frost tolerance
Tender: frost damages seedlings
Soil temperature
Sow at 50°F+ soil
Days to harvest
55–110 days, by variety

The rule we use

Sow them where they'll grow

Sunflowers grow a long taproot and don't like being moved, so sow them straight into the ground. Plant seeds 1 inch deep and 6 inches apart, then thin to about 12 inches for branching types and 18–24 inches for giant single-stem types.

Birds and squirrels dig up and eat the seed. Cover the row with netting or a bit of floating row cover until the seedlings are a few inches tall.

Stagger sowings for weeks of flowers

Single-stem sunflowers bloom once. For cut flowers all summer, sow a short row every 2–3 weeks from the last frost until about 10 weeks before your first fall frost, depending on the variety's days to bloom.

Branching varieties keep sending up side flowers for weeks, so they need fewer sowings.

Light, wind and harvest

Sunflowers need full sun, at least 6–8 hours a day. Tall types can blow over in summer storms; plant them by a fence or stake them.

For seeds to eat or feed birds, wait until the back of the head turns yellow-brown and the petals drop. Cover the heads with paper bags or netting to keep birds off, then cut and hang them to finish drying.

Seeds and supplies for sunflowers

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Questions about planting sunflowers

What month do you plant sunflowers?

Usually April in the South and May or early June farther north, after the last frost. Enter your ZIP above for dates.

Can I plant sunflowers in July?

Yes, fast varieties sown in early to mid-July usually bloom before fall frost in most areas. Check your days to first frost first.

Should I start sunflowers indoors?

There's little need. They sprout fast in warm soil, and their taproots dislike being moved.

Sources

More crop guides