When to Plant Sunflowers
flower · half-hardy · ~80 days to harvest
Planting time for sunflowers is set by your frost dates, not by the calendar month. Sow directly in the garden around your last frost, once the soil has warmed. From there it takes roughly 80 days to the first harvest. Sunflowers is a half-hardy crop, and a single light frost ends it, so both ends of its season are hard boundaries. Pick your zone below for exact dates, or find your zone by ZIP if you are not sure which one you are in.
When to plant sunflowers by zone
| Zone | Last frost | Sow | In the ground | Spring harvest | Fall sow-by |
|---|---|---|---|---|---|
| Zone 3a | May 15 | May 22 | May 22 | Aug 10 | — |
| Zone 3b | May 13 | May 20 | May 20 | Aug 8 | — |
| Zone 4a | May 10 | May 17 | May 17 | Aug 5 | — |
| Zone 4b | May 5 | May 12 | May 12 | Jul 31 | — |
| Zone 5a | Apr 30 | May 7 | May 7 | Jul 26 | — |
| Zone 5b | Apr 25 | May 2 | May 2 | Jul 21 | — |
| Zone 6a | Apr 20 | Apr 27 | Apr 27 | Jul 16 | — |
| Zone 6b | Apr 15 | Apr 22 | Apr 22 | Jul 11 | — |
| Zone 7a | Apr 10 | Apr 17 | Apr 17 | Jul 6 | — |
| Zone 7b | Apr 3 | Apr 10 | Apr 10 | Jun 29 | — |
| Zone 8a | Mar 25 | Apr 1 | Apr 1 | Jun 20 | — |
| Zone 8b | Mar 15 | Mar 22 | Mar 22 | Jun 10 | — |
| Zone 9a | Mar 1 | Mar 8 | Mar 8 | May 27 | — |
| Zone 9b | Feb 15 | Feb 22 | Feb 22 | May 13 | — |
| Zone 10a | Jan 31 | Feb 7 | Feb 7 | Apr 28 | — |
| Zone 10b | Jan 15 | Jan 22 | Jan 22 | Apr 12 | — |
| Zone 11a | none | Feb 1 | Feb 1 | Apr 22 | Oct onward |
| Zone 11b | none | Feb 1 | Feb 1 | Apr 22 | Oct onward |
| Zone 12a | none | Feb 1 | Feb 1 | Apr 22 | Oct onward |
| Zone 12b | none | Feb 1 | Feb 1 | Apr 22 | Oct onward |
| Zone 13a | none | Feb 1 | Feb 1 | Apr 22 | Oct onward |
| Zone 13b | none | Feb 1 | Feb 1 | Apr 22 | Oct onward |
Dates use the representative frost window for each zone. Your own ZIP will differ by a week or two: look it up here.
Planting sunflowers in fall
Sunflowers need a long run of warm, long days and will not finish from a late-summer sowing outside frost-free zones.
For the whole-garden version of this arithmetic, see the fall planting calendar by zone, and how to read and stretch your first frost date.
When to plant sunflowers in 12 US cities
These use each city's own NOAA frost dates rather than its zone average, which is why two cities in the same zone can differ by a week or more. Texas alone spans a wide range: in Houston (Zone 9a) sunflowers go in around Feb 20 in spring; in Dallas (Zone 8a) sunflowers go in around Mar 15 in spring.
| City | Zone | Last frost | In the ground (spring) | Fall sow-by |
|---|---|---|---|---|
| New York, NY | 7b | Mar 30 | Apr 6 | — |
| Los Angeles, CA | 10b | none | Oct to Feb (cool season) | — |
| Chicago, IL | 6a | Apr 16 | Apr 23 | — |
| Houston, TX | 9a | Feb 13 | Feb 20 | — |
| Phoenix, AZ | 9b | none | Oct to Feb (cool season) | — |
| Philadelphia, PA | 7b | Apr 2 | Apr 9 | — |
| Atlanta, GA | 8a | Mar 15 | Mar 22 | — |
| Dallas, TX | 8a | Mar 8 | Mar 15 | — |
| Denver, CO | 6a | May 5 | May 12 | — |
| Seattle, WA | 8b | Mar 2 | Mar 9 | — |
| Minneapolis, MN | 4b | Apr 23 | Apr 30 | — |
| Miami, FL | 11a | none | Oct to Feb (cool season) | — |
What to plant with sunflowers
Sunflowers grow well next to corn and cucumbers. Keep them away from potatoes and beans (bush). Roots release compounds documented to suppress growth in potatoes and beans planted too close. The full grid for all 24 crops is in the companion planting chart.
Sunflowers zone pages
More on growing sunflowers
- Last frost date and what to plant before it
Why sunflowers can go out before your last frost, and how far before.
- Companion planting chart
What to plant with sunflowers and what to keep away from it.
Frequently asked questions
When can I plant sunflowers?
As soon as your zone's soil can be worked, a few weeks before the last frost. Zone 5b: May 2; Zone 6b: Apr 22; Zone 7b: Apr 10; Zone 8b: Mar 22. Direct sow; it does not transplant well.
How long does sunflowers take to grow?
About 80 days from transplant or sowing to harvest.
Is sunflowers frost-hardy?
Sunflowers is a half-hardy crop. It handles light frost but not a hard freeze.
Can you plant sunflowers in the fall?
No. Sunflowers need a long run of warm, long days and will not finish from a late-summer sowing outside frost-free zones.
What is the latest I can plant sunflowers?
Sunflowers has to go in early enough to finish before your first frost, so the last useful planting is the spring or early summer one for your zone.