When to plant summer squash / zucchini in Detroit
Summer squash / Zucchini is frost-tender, so every date keys off Detroit's last spring frost of Apr 15.
Step 1 · Sow
Start seeds indoors
Apr 15 – May 6
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
May 31 – Jun 21
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jul 15 – Jul 30
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
Detroit's 194-day season leaves this much room.
Summer squash / Zucchini on Detroit'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 15
OCT 31
Common questions
When can I sow summer squash / zucchini outdoors in Detroit?
Direct-sow around late May (May 31–Jun 21) in Detroit, based on its local frost dates. Confidence 85%.
When will summer squash / zucchini be ready to harvest in Detroit?
Expect to harvest from around mid July (Jul 15–Jul 30) in Detroit, based on its local frost dates. Confidence 79%.
When should I start summer squash / zucchini seeds indoors in Detroit?
Start seeds indoors around mid April (Apr 15–May 6) in Detroit, based on its local frost dates. Confidence 84%.
When can I transplant summer squash / zucchini outdoors in Detroit?
Transplant outdoors around late May (May 31–Jun 21) in Detroit, based on its local frost dates. Confidence 85%.
How long is the growing season in Detroit?
Detroit has roughly 194 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 Detroit's frost dates.
Confidence 88/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.