When to plant scallion (green onion) in Colorado
Colorado spans USDA zones 5b–7a, so the right time to plant scallion (green onion) shifts by weeks across the state. The window to sow seed directly outdoors runs from about March 17 in Grand Junction to May 24 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 | April 6 – May 18 |
| Colorado Springs | 6a | May 3 | October 8 | April 5 – May 17 |
| Aurora | 6a | May 7 | October 8 | April 9 – May 21 |
| Fort Collins | 5b | May 2 | October 7 | April 4 – May 16 |
| Lakewood | 6a | May 3 | October 7 | April 5 – May 17 |
| Thornton | 6a | May 2 | October 11 | April 4 – May 16 |
| Arvada | 6a | May 5 | October 5 | April 7 – May 19 |
| Westminster | 6a | May 2 | October 11 | April 4 – May 16 |
Scallion (Green Onion) in Colorado: FAQ
When can I plant scallion (green onion) in Colorado?
Across Colorado, the time to direct-sow scallion (green onion) spans roughly March 17 in Grand Junction to May 24 in Edwards, each following that city's local frost dates.
Does the scallion (green onion) planting date vary across Colorado?
Yes. Colorado publishes 70 cities with their own frost dates, so the right scallion (green onion) 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 scallion (green onion) take to grow in Colorado?
Scallion (Green Onion) takes about 60–80 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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