When to plant sunflowers in zone 9a
In zone 9a, where the last spring frost typically comes around March 2, sow outdoors March 2 to 23.
The zone 9a schedule for sunflowers
- Sow outdoors
- March 2 to 23
- Safest planting date (10% frost risk)
- March 25
- First harvest, roughly
- April 21 to June 21
From the median frost dates of the NOAA stations assigned to the 1,736 ZIP codes in zone 9a, and the timing recommended by Cooperative Extension guides for sunflowers.
Frost risk in zone 9a
Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 9a, the typical last frost ranges from about February 13 in the earliest tenth of ZIP codes to March 21 in the latest tenth, and the first fall frost from November 14 to December 9. For a typical place in the zone:
- February 4Risky: a later frost happens in 9 years out of 10
- March 2Typical: frost after this date in half of years
- March 25Safe: a later frost only 1 year in 10
Sunflowers are killed by frost, so if you want to be safe, plant out after the safe date rather than the typical one, or be ready to cover plants on a cold night.
Your dates for sunflowers
Set your ZIP code at the top of the page and we will work out when to plant sunflowers where you live, from the frost records of the nearest NOAA weather station. Your ZIP code is remembered on this device only.
Sunflowers in zone 9a cities
| City | Typical last frost | Plant | Fall |
|---|---|---|---|
| Austin, TX | Feb 20 | Feb 20 to Mar 13 | — |
| Seattle, WA | Mar 8 | Apr 12 to May 3 | — |
| Portland, OR | Mar 13 | Mar 29 to Apr 19 | — |
| Tucson, AZ | Feb 5 | Feb 5 to 26 | — |
| North Las Vegas, NV | Jan 20 | Jan 21 to Feb 11 | — |
| Baton Rouge, LA | Feb 25 | Feb 25 to Mar 18 | — |
| Tallahassee, FL | Mar 11 | Mar 11 to Apr 1 | — |
| Mobile, AL | Feb 21 | Feb 21 to Mar 14 | — |
| Palmdale, CA | Mar 10 | Mar 10 to 31 | — |
| Charleston, SC | Feb 4 | Feb 4 to 25 | — |
| Savannah, GA | Mar 2 | Mar 2 to 23 | — |
| Gainesville, FL | Mar 3 | Mar 3 to 24 | — |
How to grow sunflowersAll zonesSunflowers in zone 8bSunflowers in zone 9bAbout zone 9a
Sources
- Dakota Gardener: Grow a bouquet in 60 days · NDSU Extension (North Dakota State University)
- Growing Sunflowers in the Home Garden (Circular 1121) · University of Georgia Cooperative Extension
- Let's Grow Sunflowers · Clemson Cooperative Extension Home & Garden Information Center
- How to sow sunflowers in successful succession · Mississippi State University Extension
- How to Grow Sunflowers (Garden Notes GN 166) · UC ANR Cooperative Extension Sacramento County Master Gardeners
- Sunflowers · UF/IFAS Extension Gardening Solutions
- Flowers to Plant in Florida: Text (month-by-month calendar for North, Central and South Florida) · UF/IFAS Extension Gardening Solutions
- Flower Planting Guide for the Low Desert (AZ1100) · University of Arizona Cooperative Extension, Maricopa County
- Sowing Annual Seeds · Penn State Extension
- May 21, 2005 Timely Tips (Bexar County gardening calendar) · Texas A&M AgriLife Extension, Bexar County