When to plant onions in Arizona

Onions
Plant out in Phoenix
Nov 27–Dec 18

Across Arizona the window opens between November 23 and April 23. Find your city below; the dates follow each town's own average last frost.

Start indoors, Phoenix
Oct 16–Nov 13
Plant out, Phoenix
Nov 27–Dec 18
Last frost, Phoenix
Jan 8

Start seeds indoors 8–12 weeks before the last frost; plant out 3–6 weeks before the last frost. Northern gardens need long-day varieties and southern gardens need short-day ones. A wrong pick gives small bulbs.

Onions planting dates by city

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
JanFebMarAprMayJunJulAugSepOctNovDec
PhoenixNov 27–Dec 18
TucsonDec 25–Jan 15
GilbertDec 21–Jan 11
ChandlerJan 2–Jan 23
GlendaleDec 9–Dec 30
ScottsdaleDec 16–Jan 6
TempeJan 2–Jan 23
GoodyearDec 3–Dec 24
San Tan ValleyDec 21–Jan 11
AvondaleDec 3–Dec 24
Queen CreekDec 21–Jan 11
MaricopaJan 12–Feb 2
FlagstaffApr 23–May 14
Casas AdobesJan 15–Feb 5
Casa GrandeDec 25–Jan 15
Lake Havasu CityNov 24–Dec 15
Prescott ValleyMar 19–Apr 9
Catalina FoothillsJan 9–Jan 30
PrescottMar 19–Apr 9
Sierra VistaFeb 22–Mar 15
Bullhead CityNov 23–Dec 14
Sun CityDec 9–Dec 30
KingmanFeb 19–Mar 12
El MirageDec 9–Dec 30
Fortuna FoothillsNov 23–Dec 14
Drexel HeightsDec 25–Jan 15
FlorenceDec 19–Jan 9
Rio RicoMar 5–Mar 26

Questions

When should I plant onions in Arizona?

In Phoenix, plant out from November 27 to December 18. Across Arizona the window opens between November 23 and April 23, depending on the local last frost.

How is this date worked out?

Start seeds indoors 8–12 weeks before the last frost; plant out 3–6 weeks before the last frost. Frost dates are NOAA 1991–2020 averages for the weather station nearest each city.

More for Arizona

Onions in other states

Frost dates for every city in Arizona