Denver Gardening Guide (2026)
High altitude; short season, intense sun.
USDA zone
6
Typical last frost
05/05
Typical first frost
10/05
Quick answer (Denver): Gardeners here work in about a 153-day frost-free window around zone 6. State context: Colorado (zones 3–7). Start warm crops indoors ~6 weeks before the last frost of 05/05.
Your Denver planting calendar
Pre-filled with Denver's frost dates. Choose a crop to print your plan.
In Colorado (typical zone 3–7, last frost ≈ May 5, first frost ≈ Oct 5, 153-day season), your Tomato plan:
Start seeds indoors
Mar 24
Sow / transplant outdoors
May 19
First harvest
Jul 28
Spacing / depth
24″ / 0.25″
Month-by-month (Colorado, 2026)
| Month | Action |
|---|---|
| Jan | — |
| Feb | — |
| Mar | Start indoors |
| Apr | — |
| May | Sow · Transplant |
| Jun | — |
| Jul | Harvest |
| Aug | — |
| Sep | — |
| Oct | — |
| Nov | — |
| Dec | — |
Start indoors 6 weeks before last frost; transplant after soil warms. Zones 3–13 suitable. Dates are typical; confirm with your county extension and watch the 10-day forecast.