When to plant watermelons in zone 6a
In zone 6a, where the last spring frost typically comes around April 29, start watermelons indoors April 14 to 28 and plant out May 19 to June 2.
The zone 6a schedule for watermelons
- Start seeds indoors
- April 14 to 28
- Plant out
- May 19 to June 2
- Sow outdoors
- May 19 to June 2
- Soil warm enough (60°F), about
- May 19
- First harvest, roughly
- July 18 to August 31
From the median frost dates of the NOAA stations assigned to the 4,514 ZIP codes in zone 6a, and the timing recommended by Cooperative Extension guides for watermelons.
Frost risk in zone 6a
Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 6a, the typical last frost ranges from about April 16 in the earliest tenth of ZIP codes to May 11 in the latest tenth, and the first fall frost from October 4 to October 24. For a typical place in the zone:
- April 16Risky: a later frost happens in 9 years out of 10
- April 29Typical: frost after this date in half of years
- May 14Safe: 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 6a cities
| City | Typical last frost | Start indoors | Plant out |
|---|---|---|---|
| Chicago, IL | Apr 11 | Apr 7 to 21 | May 12 to 26 |
| Indianapolis city, IN | Apr 15 | Mar 31 to Apr 14 | May 5 to 19 |
| Denver, CO | May 4 | Apr 17 to May 1 | May 22 to Jun 5 |
| Colorado Springs, CO | May 3 | Apr 19 to May 3 | May 24 to Jun 7 |
| Omaha, NE | Apr 18 | Apr 2 to 16 | May 7 to 21 |
| Aurora, CO | May 4 | Apr 17 to May 1 | May 22 to Jun 5 |
| Lincoln, NE | Apr 24 | Apr 4 to 18 | May 9 to 23 |
| Fort Wayne, IN | Apr 24 | Apr 7 to 21 | May 12 to 26 |
| Grand Rapids, MI | Apr 29 | Apr 14 to 28 | May 19 to Jun 2 |
| Lakewood, CO | May 5 | Apr 20 to May 4 | May 25 to Jun 8 |
| Springfield, MA | May 3 | Apr 15 to 29 | May 20 to Jun 3 |
| Joliet, IL | Apr 19 | Apr 11 to 25 | May 16 to 30 |
How to grow watermelonsAll zonesWatermelons in zone 5bWatermelons in zone 6bAbout zone 6a
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