When to plant Onions in Arizona
In spring, from Jan 1 – 15 in Apache Junction to May 1 – 30 in Flagstaff.
In fall, from Sept 1 – Oct 15 in Cottonwood to Oct 1 – Dec 31 in Yuma.
Dates are for setting out plants. USDA's earliest safe spring and latest safe fall planting dates, matched to each place's average frost dates.
| Place | Spring | Fall |
|---|---|---|
| Apache Junction | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Avondale | — | Oct 1 – Dec 31Now |
| Buckeye | — | Oct 1 – Dec 31Now |
| Bullhead City | — | Oct 1 – Dec 31Now |
| Camp Verde | Mar 15 – Apr 10 | Not listed |
| Casa Grande | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Chandler | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Chino Valley | Apr 1 – May 1 | Spring-planted |
| Coolidge | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Cottonwood | Feb 15 – Mar 15 | Sept 1 – Oct 15 |
| Douglas | Feb 10 – Mar 10 | Sept 1 – Oct 15 |
| El Mirage | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Eloy | Jan 1 – Feb 1 | Oct 1 – Dec 31Now |
| Flagstaff | May 1 – 30 | Spring-planted |
| Florence | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Fountain Hills | — | Oct 1 – Dec 31Now |
| Gilbert | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Glendale | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Goodyear | — | Oct 1 – Dec 31Now |
| Kingman | Feb 15 – Mar 15 | Sept 1 – Oct 15 |
| Lake Havasu City | — | Oct 1 – Dec 31Now |
| Marana | Feb 15 – Mar 15 | Sept 1 – Oct 15 |
| Maricopa | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Mesa | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Nogales | Feb 10 – Mar 10 | Oct 1 – Dec 31Now |
| Oro Valley | Feb 15 – Mar 15 | Sept 1 – Oct 15 |
| Paradise Valley | — | Oct 1 – Dec 31Now |
| Payson | Apr 1 – May 1 | Spring-planted |
| Peoria | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Phoenix | — | Oct 1 – Dec 31Now |
| Prescott | Apr 1 – May 1 | Spring-planted |
| Prescott Valley | Apr 1 – May 1 | Spring-planted |
| Queen Creek | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Safford | Feb 10 – Mar 10 | Sept 1 – Oct 15 |
| Sahuarita | Jan 1 – Feb 1 | Oct 1 – Dec 31Now |
| San Luis | — | Oct 1 – Dec 31Now |
| Scottsdale | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Show Low | Apr 1 – May 1 | Spring-planted |
| Sierra Vista | Mar 1 – Apr 1 | Sept 1 – Oct 15 |
| Somerton | — | Oct 1 – Dec 31Now |
| Surprise | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Tempe | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Tucson | Jan 1 – 15 | Oct 1 – Dec 31Now |
| Yuma | — | Oct 1 – Dec 31Now |
Planting dates: USDA Home and Garden Bulletin No. 9 (1967), tables 4 and 5. Frost dates: NOAA U.S. Climate Normals 1991–2020. “—” means the place's frost date is outside the table. The full USDA table for onion plants.