Denver, CO · zone 6a · ~164 frost-free days
When to plant a garden in Denver.
In Denver, the typical last spring frost lands around Apr 30 and the first fall frost around Oct 11, giving you about 164 frost-free days. Cool-season crops go out before the last frost; warm-season crops wait until after it.
The 2026 windows
Sow dates for Denver, keyed to your frost.
| Crop | Start indoors | Spring sow / set out | Fall sow |
|---|---|---|---|
| Tomato, slicing | Mar 26 to May 26 | May 7 to Jul 7 | — |
| Lettuce, leaf | — | Mar 23 to May 7 | Jul 28 to Sep 26 |
| Carrot | — | Mar 23 to Apr 25 | Jul 16 to Aug 11 |
| Bush Bean | — | Apr 30 to Jun 20 | Jun 27 to Jul 30 |
| Cucumber, slicing | — | May 7 to Aug 6 | Jun 10 to Jul 11 |
| Pepper, bell | Apr 4 to May 26 | May 16 to Jul 7 | — |
| Kale | Feb 9 to Mar 9 | Mar 23 to Apr 20 | Jul 11 to Aug 26 |
| Spinach | — | Mar 9 to Apr 20 | Jul 28 to Sep 15 |
Denver sits in Zone 6a, but two gardens in the same city can be a week or two apart. The planner works from your ZIP code's frost dates, not the zone, so the dates land right for your block, not the metro average.
Build your Denver garden plan.
Tell the free planner what you want to eat and who you're feeding. It returns plant counts, spacing, and frost-safe sow dates for ZIP 80202 in about 60 seconds.