When to plant broccoli in Colorado
Colorado spans USDA zones 5b–7a, so the right time to plant broccoli shifts by weeks across the state. The window to transplant seedlings outdoors runs from about March 24 in Grand Junction to May 31 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 | April 13 – April 27 |
| Colorado Springs | 6a | May 3 | October 8 | April 12 – April 26 |
| Aurora | 6a | May 7 | October 8 | April 16 – April 30 |
| Fort Collins | 5b | May 2 | October 7 | April 11 – April 25 |
| Lakewood | 6a | May 3 | October 7 | April 12 – April 26 |
| Thornton | 6a | May 2 | October 11 | April 11 – April 25 |
| Arvada | 6a | May 5 | October 5 | April 14 – April 28 |
| Westminster | 6a | May 2 | October 11 | April 11 – April 25 |
Broccoli in Colorado: FAQ
When can I plant broccoli in Colorado?
Across Colorado, the time to transplant broccoli spans roughly March 24 in Grand Junction to May 31 in Edwards, each following that city's local frost dates.
Does the broccoli planting date vary across Colorado?
Yes. Colorado publishes 70 cities with their own frost dates, so the right broccoli 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 broccoli take to grow in Colorado?
Broccoli takes about 55–80 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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