When to plant watermelon in Colorado
Colorado spans USDA zones 5b–7a, so the right time to plant watermelon shifts by weeks across the state. The window to transplant seedlings outdoors runs from about April 21 in Grand Junction to June 28 in Edwards — below are local dates for 70 cities, each computed from its own frost dates.
| City | Zone | Last frost | First frost | Transplant out |
|---|---|---|---|---|
| Denver | 6a | May 4 | October 8 | May 11 – May 18 |
| Colorado Springs | 6a | May 3 | October 8 | May 10 – May 17 |
| Aurora | 6a | May 7 | October 8 | May 14 – May 21 |
| Fort Collins | 5b | May 2 | October 7 | May 9 – May 16 |
| Lakewood | 6a | May 3 | October 7 | May 10 – May 17 |
| Thornton | 6a | May 2 | October 11 | May 9 – May 16 |
| Arvada | 6a | May 5 | October 5 | May 12 – May 19 |
| Westminster | 6a | May 2 | October 11 | May 9 – May 16 |
Watermelon in Colorado: FAQ
When can I plant watermelon in Colorado?
Across Colorado, the time to transplant watermelon spans roughly April 21 in Grand Junction to June 28 in Edwards, each following that city's local frost dates.
Does the watermelon planting date vary across Colorado?
Yes. Colorado publishes 70 cities with their own frost dates, so the right watermelon planting window shifts by weeks between the warmest and coldest parts of the state — use your city's page for the exact dates.
How long does watermelon take to grow in Colorado?
Watermelon takes about 75–95 days to reach harvest once planted — check that this fits inside your city's frost-free season on its place page.
Never miss a window in your area
An email when it’s time to start seeds, transplant, and sow — timed to your frost dates. Double opt-in, one-click unsubscribe, no spam.