When to plant watermelons in zone 5a
In zone 5a, where the last spring frost typically comes around May 3, start watermelons indoors April 18 to May 2 and plant out May 23 to June 6.
The zone 5a schedule for watermelons
- Start seeds indoors
- April 18 to May 2
- Plant out
- May 23 to June 6
- Sow outdoors
- May 23 to June 6
- Soil warm enough (60°F), about
- May 23
- First harvest, roughly
- July 22 to September 4
From the median frost dates of the NOAA stations assigned to the 2,200 ZIP codes in zone 5a, and the timing recommended by Cooperative Extension guides for watermelons.
Frost risk in zone 5a
Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 5a, the typical last frost ranges from about April 27 in the earliest tenth of ZIP codes to May 21 in the latest tenth, and the first fall frost from September 25 to October 13. For a typical place in the zone:
- April 20Risky: a later frost happens in 9 years out of 10
- May 3Typical: frost after this date in half of years
- May 17Safe: 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 5a cities
| City | Typical last frost | Start indoors | Plant out |
|---|---|---|---|
| Minneapolis, MN | Apr 23 | Apr 14 to 28 | May 19 to Jun 2 |
| St. Paul, MN | Apr 23 | Apr 14 to 28 | May 19 to Jun 2 |
| Anchorage, AK | May 5 | Apr 7 to 21 | May 12 to 26 |
| Sioux Falls, SD | May 1 | Apr 13 to 27 | May 18 to Jun 1 |
| Cedar Rapids, IA | Apr 28 | Apr 6 to 20 | May 11 to 25 |
| Billings, MT | May 10 | Apr 28 to May 12 | Jun 2 to 16 |
| Bloomington, MN | Apr 23 | Apr 12 to 26 | May 17 to 31 |
| Sioux City, IA | Apr 29 | Apr 10 to 24 | May 15 to 29 |
| Brooklyn Park, MN | Apr 30 | Apr 16 to 30 | May 21 to Jun 4 |
| Woodbury, MN | Apr 24 | Apr 14 to 28 | May 19 to Jun 2 |
| Plymouth, MN | Apr 29 | Apr 16 to 30 | May 21 to Jun 4 |
| Blaine, MN | Apr 30 | Apr 16 to 30 | May 21 to Jun 4 |
How to grow watermelonsAll zonesWatermelons in zone 4bWatermelons in zone 5bAbout zone 5a
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