When to plant melon (cantaloupe/watermelon) in Osaka
Melon (cantaloupe/watermelon) is frost-tender, so every date keys off Osaka's last spring frost of Apr 10.
Step 1 · Sow
Start seeds indoors
Apr 1 – Apr 22
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Jun 27 – Jul 18
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Sep 10 – Oct 5
Picking runs until conditions turn against the crop.
Window
Days to maturity
75 – 100 d
Osaka's 228-day season leaves this much room.
Melon (cantaloupe/watermelon) 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
FROST
APR 10
NOV 22
Common questions
When can I sow melon (cantaloupe/watermelon) outdoors in Osaka?
Direct-sow around late June (Jun 27–Jul 18) in Osaka, based on its local frost dates. Confidence 44%.
When will melon (cantaloupe/watermelon) be ready to harvest in Osaka?
Expect to harvest from around early September (Sep 10–Oct 5) in Osaka, based on its local frost dates. Confidence 40%.
When should I start melon (cantaloupe/watermelon) seeds indoors in Osaka?
Start seeds indoors around early April (Apr 1–Apr 22) in Osaka, based on its local frost dates. Confidence 43%.
When can I transplant melon (cantaloupe/watermelon) outdoors in Osaka?
Transplant outdoors around late June (Jun 27–Jul 18) in Osaka, based on its local frost dates. Confidence 44%.
How long is the growing season in Osaka?
Osaka has roughly 228 frost-free days, which is enough time to grow melon (cantaloupe/watermelon) to maturity outdoors.
The rule of thumb
Sow melon (cantaloupe/watermelon) 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 45/100 · Curated · based on NASA POWER (modeled) 1991–2020 · frost dates are probabilities, not guarantees.