When to plant in Colorado
Most of Colorado sees its last spring frost between Apr 30 and Jun 11, and its first fall frost between Sep 12 and Oct 12. The middle of the state is around May 7 and October 6: that's what the dates below use.
Hardiness zones in Colorado: 5a (12%), 5b (35%), 6a (43%), 6b (6%).
Planting dates for common crops
| Crop | Start indoors | Plant outside | Harvest | Plant for fall |
|---|---|---|---|---|
| Tomato | Apr 2 | May 21 – Jun 4 | Jul 30 – Oct 6 | — |
| Pepper | Mar 19 | May 21 – Jun 4 | Aug 4 – Oct 6 | — |
| Cucumber | — | May 21 – Jun 4 | Jul 15 – Sep 2 | — |
| Zucchini / Summer squash | — | May 21 – Jun 4 | Jul 10 – Sep 18 | — |
| Winter squash | — | May 21 – Jun 4 | Aug 24 – Sep 28 | — |
| Green beans (bush) | — | May 21 – Jun 4 | Jul 15 – Aug 26 | — |
| Peas | — | Mar 26 – Apr 9 | May 25 – Jun 29 | Jul 17 – Jul 31 |
| Sweet corn | — | May 21 – Jun 4 | Aug 4 – Sep 1 | — |
| Lettuce | — | Apr 9 – Apr 23 | May 24 – Jul 5 | Aug 8 – Aug 22 |
| Spinach | — | Mar 26 – Apr 9 | May 5 – Jun 16 | Aug 27 – Sep 10 |
| Kale | Feb 26 | Apr 9 – Apr 23 | Jun 3 – Aug 26 | Aug 26 – Sep 9 |
| Broccoli | Mar 5 | Apr 16 – Apr 30 | Jun 15 – Jul 20 | Jul 31 – Aug 14 |
| Cabbage | Feb 26 | Apr 9 – Apr 23 | Jun 18 – Jul 23 | Jul 28 – Aug 11 |
| Carrot | — | Apr 16 – Apr 30 | Jun 25 – Aug 6 | Jul 28 – Aug 11 |
| Beet | — | Apr 16 – Apr 30 | Jun 10 – Jul 22 | Aug 5 – Aug 19 |
| Radish | — | Apr 2 – Apr 16 | Apr 27 – May 25 | Aug 28 – Sep 11 |
| Onion (sets) | — | Apr 2 – Apr 16 | Jul 11 – Aug 15 | — |
| Garlic | — | Sep 29 – Oct 20 (fall) | Jul 2 – Jul 23 next year | — |
| Potato | — | Apr 16 – Apr 30 | Jul 15 – Aug 19 | — |
| Sweet potato | Apr 16 | May 28 – Jun 11 | Sep 5 – Oct 3 | — |
| Watermelon | — | May 28 – Jun 11 | Aug 21 – Sep 25 | — |
| Basil | Apr 9 | May 21 – Jun 4 | Jun 20 – Sep 26 | — |
| Strawberry (June-bearing) | — | Apr 16 – Apr 30 | Jun 4 – Jul 2 (once established) | — |
| Sunflower | — | May 21 – Jun 4 | Aug 9 – Sep 13 | — |
Dates for a typical spot in Colorado. Colder and higher places plant later, warmer ones earlier: enter your ZIP code for yours, or see the calendar for your zone.
Frost dates around Colorado
| Place | Zone | Last frost | First frost |
|---|---|---|---|
| Denver | 6a | May 2 | Oct 11 |
| Colorado Springs | 6a | May 3 | Oct 8 |
| Aurora | 6a | May 5 | Oct 8 |
| Littleton | 6a | May 5 | Oct 9 |
| Pueblo | 6a | Apr 30 | Oct 9 |
| Boulder | 6a | May 6 | Oct 5 |
| Fort Collins | 5b | May 3 | Oct 6 |
| Arvada | 6a | May 5 | Oct 5 |
| Englewood | 6a | May 5 | Oct 9 |
| Grand Junction | 7a | Apr 14 | Oct 23 |
Average dates from the nearest NOAA weather stations (1991–2020). Click a place for its full planting calendar.