When to plant summer squash / zucchini in Tokyo
Summer squash / Zucchini is frost-tender, so every date keys off Tokyo's last spring frost of Mar 28.
Step 1 · Sow
Start seeds indoors
Mar 26 – Apr 16
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
May 11 – Jun 1
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jun 25 – Jul 10
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
Tokyo's 258-day season leaves this much room.
Summer squash / Zucchini on Tokyo'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 28
DEC 11
Common questions
When can I sow summer squash / zucchini outdoors in Tokyo?
Direct-sow around mid May (May 11–Jun 1) in Tokyo, based on its local frost dates. Confidence 44%.
When will summer squash / zucchini be ready to harvest in Tokyo?
Expect to harvest from around late June (Jun 25–Jul 10) in Tokyo, based on its local frost dates. Confidence 40%.
When should I start summer squash / zucchini seeds indoors in Tokyo?
Start seeds indoors around late March (Mar 26–Apr 16) in Tokyo, based on its local frost dates. Confidence 43%.
When can I transplant summer squash / zucchini outdoors in Tokyo?
Transplant outdoors around mid May (May 11–Jun 1) in Tokyo, based on its local frost dates. Confidence 44%.
How long is the growing season in Tokyo?
Tokyo 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 Tokyo's frost dates.
Confidence 45/100 · Curated · based on NASA POWER (modeled) 1991–2020 · frost dates are probabilities, not guarantees.