When to plant butternut squash in Colorado
Colorado spans USDA zones 5b–7a, so the right time to plant butternut squash shifts by weeks across the state. The window to sow seed directly 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 | Direct sow |
|---|---|---|---|---|
| Denver | 6a | May 4 | October 8 | May 11 – May 25 |
| Colorado Springs | 6a | May 3 | October 8 | May 10 – May 24 |
| Aurora | 6a | May 7 | October 8 | May 14 – May 28 |
| Fort Collins | 5b | May 2 | October 7 | May 9 – May 23 |
| Lakewood | 6a | May 3 | October 7 | May 10 – May 24 |
| Thornton | 6a | May 2 | October 11 | May 9 – May 23 |
| Arvada | 6a | May 5 | October 5 | May 12 – May 26 |
| Westminster | 6a | May 2 | October 11 | May 9 – May 23 |
Butternut Squash in Colorado: FAQ
When can I plant butternut squash in Colorado?
Across Colorado, the time to direct-sow butternut squash spans roughly April 21 in Grand Junction to June 28 in Edwards, each following that city's local frost dates.
Does the butternut squash planting date vary across Colorado?
Yes. Colorado publishes 70 cities with their own frost dates, so the right butternut squash 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 butternut squash take to grow in Colorado?
Butternut Squash takes about 90–110 days to reach harvest once planted — check that this fits inside your city's frost-free season on its place page.
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