When to plant summer squash / zucchini in Phoenix
Summer squash / Zucchini is frost-tender, so every date keys off Phoenix's last spring frost of Jan 27.
Step 1 · Sow
Start seeds indoors
Jan 27 – Feb 17
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Mar 14 – Apr 4
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Apr 28 – May 13
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
Phoenix's 314-day season leaves this much room.
Summer squash / Zucchini on Phoenix's growing year
Frost-bounded season with crops mapped onto the 12-month axis.
Frost risk Growing Harvest
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
JAN 27
DEC 7
Common questions
When can I sow summer squash / zucchini outdoors in Phoenix?
Direct-sow around mid March (Mar 14–Apr 4) in Phoenix, based on its local frost dates. Confidence 80%.
When will summer squash / zucchini be ready to harvest in Phoenix?
Expect to harvest from around late April (Apr 28–May 13) in Phoenix, based on its local frost dates. Confidence 74%.
When should I start summer squash / zucchini seeds indoors in Phoenix?
Start seeds indoors around late January (Jan 27–Feb 17) in Phoenix, based on its local frost dates. Confidence 78%.
When can I transplant summer squash / zucchini outdoors in Phoenix?
Transplant outdoors around mid March (Mar 14–Apr 4) in Phoenix, based on its local frost dates. Confidence 80%.
How long is the growing season in Phoenix?
Phoenix has roughly 314 frost-free days, which is enough time to grow summer squash / zucchini to maturity outdoors.
The rule of thumb
Sow summer squash / zucchini 6–8 weeks before your last spring frost; plant out 2–3 weeks after it. Every date on this page is derived from that rule and Phoenix's frost dates.
Confidence 82/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.