Flagstaff, AZ · zone 5b · ~100 frost-free days
When to plant in Flagstaff: frost dates and zone 5b.
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 May 16 | Jun 21 to Jun 27 | — |
| 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 Jul 11 | — |
| Cucumber, slicing | — | Jun 21 to Jul 6 | — |
| 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.
Flagstaff planting questions
What planting zone is Flagstaff, AZ?+
Flagstaff is in USDA hardiness zone 5b. Growing zone, gardening zone, and planting zone all mean the same thing: the USDA number, 5b here. It tells you what survives winter, not when to plant. Frost dates set your planting time, and the free planner uses your exact ZIP code's frost dates, which can differ by weeks across one metro.
When is the last frost date in Flagstaff?+
The typical last spring frost in Flagstaff, AZ is around Jun 14. That is an average from local history, not a guarantee, so tender crops like tomatoes and peppers are safer with a week of buffer after it.
When is the first frost date in Flagstaff?+
The typical first fall frost in Flagstaff, AZ arrives around Sep 22, closing a growing season of roughly 100 frost-free days. Count backward from it to find the last date a fall crop can still finish.
What can I plant now in Flagstaff?+
It depends on the date. Cool-season crops like lettuce, kale, and spinach go out weeks before the last frost; warm-season crops like tomatoes and peppers wait until after Jun 14. The table above shows each crop's window; the free planner turns your ZIP into an exact, dated calendar.