When to plant watermelons in zone 9b
In zone 9b, where the last spring frost typically comes around January 31, start watermelons indoors February 1 to 15 and plant out March 8 to 22.
The zone 9b schedule for watermelons
- Start seeds indoors
- February 1 to 15
- Plant out
- March 8 to 22
- Sow outdoors
- March 8 to 22
- Soil warm enough (60°F), about
- March 8
- First harvest, roughly
- May 7 to June 20
From the median frost dates of the NOAA stations assigned to the 1,459 ZIP codes in zone 9b, and the timing recommended by Cooperative Extension guides for watermelons.
Frost risk in zone 9b
Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 9b, the typical last frost ranges from about January 12 in the earliest tenth of ZIP codes to March 1 in the latest tenth, and the first fall frost from January 8 to December 28. For a typical place in the zone:
- December 18Risky: a later frost happens in 9 years out of 10
- January 31Typical: frost after this date in half of years
- March 1Safe: a later frost only 1 year in 10
Watermelons 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 watermelons
Set your ZIP code at the top of the page and we will work out when to plant watermelons where you live, from the frost records of the nearest NOAA weather station. Your ZIP code is remembered on this device only.
Watermelons in zone 9b cities
| City | Typical last frost | Start indoors | Plant out |
|---|---|---|---|
| Houston, TX | Jan 30 | Jan 17 to 31 | Feb 21 to Mar 7 |
| Jacksonville, FL | Feb 1 | Jan 14 to 28 | Feb 18 to Mar 4 |
| San Jose, CA | Jan 12 | Mar 22 to Apr 5 | Apr 26 to May 10 |
| Fresno, CA | Jan 14 | Mar 1 to 15 | Apr 5 to 19 |
| Sacramento, CA | Jan 12 | Mar 5 to 19 | Apr 9 to 23 |
| Bakersfield, CA | Jan 17 | Feb 22 to Mar 8 | Mar 29 to Apr 12 |
| New Orleans, LA | Jan 24 | Jan 14 to 28 | Feb 18 to Mar 4 |
| Henderson, NV | Jan 20 | Feb 6 to 20 | Mar 13 to 27 |
How to grow watermelonsAll zonesWatermelons in zone 9aAbout zone 9b
Sources
- Growing Watermelon in the Home Garden · Iowa State University Extension and Outreach
- How to Grow Watermelon in Your Garden · Utah State University Extension
- Watermelon (HGIC factsheet) · Clemson Cooperative Extension Home & Garden Information Center
- Citrullus lanatus (Watermelon) · NC State Extension Gardener Plant Toolbox
- Florida Vegetable Gardening Guide (SP103/VH021) · University of Florida IFAS Extension
- Vegetable Planting Calendar for Maricopa County (AZ1005) · University of Arizona Cooperative Extension