When to plant summer squash / zucchini in Milwaukee
Summer squash / Zucchini is frost-tender, so every date keys off Milwaukee's last spring frost of Apr 23.
Step 1 · Sow
Start seeds indoors
Apr 21 – May 12
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Jun 7 – Jun 28
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jul 22 – Aug 6
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
Milwaukee's 182-day season leaves this much room.
Summer squash / Zucchini on Milwaukee'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
FROST
FROST
APR 23
OCT 23
Common questions
When can I sow summer squash / zucchini outdoors in Milwaukee?
Direct-sow around early June (Jun 7–Jun 28) in Milwaukee, based on its local frost dates. Confidence 86%.
When will summer squash / zucchini be ready to harvest in Milwaukee?
Expect to harvest from around late July (Jul 22–Aug 6) in Milwaukee, based on its local frost dates. Confidence 80%.
When should I start summer squash / zucchini seeds indoors in Milwaukee?
Start seeds indoors around late April (Apr 21–May 12) in Milwaukee, based on its local frost dates. Confidence 85%.
When can I transplant summer squash / zucchini outdoors in Milwaukee?
Transplant outdoors around early June (Jun 7–Jun 28) in Milwaukee, based on its local frost dates. Confidence 86%.
How long is the growing season in Milwaukee?
Milwaukee has roughly 182 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 Milwaukee's frost dates.
Confidence 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.