When to plant summer squash / zucchini in Osaka
Summer squash / Zucchini is frost-tender, so every date keys off Osaka's last spring frost of Mar 22.
Step 1 · Sow
Start seeds indoors
Mar 8 – Mar 29
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Mar 29 – Apr 19
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
May 13 – May 28
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
Osaka's 258-day season leaves this much room.
Summer squash / Zucchini on Osaka'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
MAR 22
DEC 5
Common questions
When can I sow summer squash / zucchini outdoors in Osaka?
Direct-sow around late March (Mar 29–Apr 19) in Osaka, based on its local frost dates. Confidence 86%.
When will summer squash / zucchini be ready to harvest in Osaka?
Expect to harvest from around mid May (May 13–May 28) in Osaka, based on its local frost dates. Confidence 77%.
When should I start summer squash / zucchini seeds indoors in Osaka?
Start seeds indoors around early March (Mar 8–Mar 29) in Osaka, based on its local frost dates. Confidence 82%.
When can I transplant summer squash / zucchini outdoors in Osaka?
Transplant outdoors around late March (Mar 29–Apr 19) in Osaka, based on its local frost dates. Confidence 86%.
How long is the growing season in Osaka?
Osaka has roughly 258 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 Osaka's frost dates.
Confidence 86/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.