Flagstaff, AZ · zone 5b · ~100 frost-free days
When to plant a garden in Flagstaff.
In Flagstaff, the typical last spring frost lands around Jun 14 and the first fall frost around Sep 22, giving you about 100 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 Flagstaff, keyed to your frost.
| Crop | Start indoors | Spring sow / set out | Fall sow |
|---|---|---|---|
| Tomato, slicing | May 10 to Jul 10 | Jun 21 to Aug 21 | — |
| Lettuce, leaf | — | May 7 to Jun 21 | Jul 9 to Sep 7 |
| Carrot | — | May 7 to Jun 9 | Jun 27 to Jul 23 |
| Bush Bean | — | Jun 14 to Aug 4 | Jun 8 to Jul 11 |
| Cucumber, slicing | — | Jun 21 to Sep 20 | May 22 to Jun 22 |
| Pepper, bell | May 19 to Jul 10 | Jun 30 to Aug 21 | — |
| Kale | Mar 26 to Apr 23 | May 7 to Jun 4 | Jun 22 to Aug 7 |
| Spinach | — | Apr 23 to Jun 4 | Jul 9 to Aug 27 |
Flagstaff sits in Zone 5b, 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 Flagstaff 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 86001 in about 60 seconds.