State growing guide
Arizona Planting Guide
USDA Zone 9a/9b · Last frost Feb 15 · First frost Dec 1 · 289 days
Zone-specific planting calendar, major city frost dates, top crops, and Duke's tips for growing food in Arizona.
Frost Dates by City — Arizona
Average frost dates for major Arizona cities. Use these to calculate your indoor start dates and transplant windows.
| City | USDA Zone | Last Spring Frost | First Fall Frost | Tomato Transplant Window |
|---|---|---|---|---|
| Phoenix | 9b | Jan 20 | Dec 15 | ~2 wks after (Jan 20) |
| Tucson | 9a | Feb 15 | Nov 25 | ~2 wks after (Feb 15) |
| Flagstaff | 6a | May 10 | Oct 1 | ~2 wks after (May 10) |
| Scottsdale | 9b | Jan 20 | Dec 15 | ~2 wks after (Jan 20) |
| Mesa | 9b | Jan 20 | Dec 15 | ~2 wks after (Jan 20) |
| Yuma | 10a | Jan 1 | Dec 31 | ~2 wks after (Jan 1) |
Average dates based on 30-year NOAA climate normals. Individual years may vary ±2 weeks. Use the Zone Lookup Tool for ZIP-specific dates.
Duke's Top Tips for Arizona Gardeners
- Phoenix has TWO growing seasons: spring (Jan–May) and fall (Aug–Nov)
- Summer temps above 110°F kill almost everything — rest the garden June–July
- Use drip irrigation — sprinklers waste water and promote fungal disease in desert heat
- Amend caliche soil with compost before planting anything
- Shade cloth (30–50%) extends spring season into late May
Common Challenges in Arizona
- ⚠ Extreme summer heat (110°F+) kills most crops June–August
- ⚠ Caliche clay soil has poor drainage and low organic matter
- ⚠ Very low humidity causes blossom drop in tomatoes
- ⚠ Whiteflies and aphids explode in spring — insecticidal soap weekly
Best Crops for Arizona
Get exact dates for your ZIP code in Arizona
City averages are a starting point. Your actual microclimate matters — enter your ZIP for precise frost dates.
Frequently Asked Questions — Arizona Gardening
What zone is Arizona?
Arizona spans multiple zones: Flagstaff is Zone 6a (cold winters), Tucson is Zone 9a, Phoenix and the Valley of the Sun are Zone 9b, and Yuma approaches Zone 10a.
When do I plant tomatoes in Arizona?
In Phoenix: start seeds indoors in late November, transplant in January–February. In Tucson: transplant in February–March. In Flagstaff: wait until late May after last frost.
Can I garden year-round in Phoenix?
Almost. Phoenix gardeners grow through spring (Jan–May) and fall (Aug–Nov), skipping the brutal June–August heat. That still gives you 8+ months of active growing.
What grows best in Arizona summer?
Not much in Phoenix — it's too hot. Exceptions: okra, Armenian cucumber, black-eyed peas, and sweet potatoes can tolerate extreme heat with heavy watering and mulch.