When to plant lettuce in Osaka
Lettuce is cold-hardy, so every date keys off Osaka's frost dates of Mar 22.
Step 1 · Sow
Start seeds indoors
Feb 22 – Mar 15
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Mar 1 – Mar 22
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Apr 15 – Apr 30
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
Osaka's 258-day season leaves this much room.
Lettuce 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 lettuce outdoors in Osaka?
Direct-sow around late February (Feb 22–Mar 15) in Osaka, based on its local frost dates. Confidence 86%.
When will lettuce be ready to harvest in Osaka?
Expect to harvest from around mid April (Apr 15–Apr 30) in Osaka, based on its local frost dates. Confidence 77%.
When should I start lettuce seeds indoors in Osaka?
Start seeds indoors around late February (Feb 22–Mar 15) in Osaka, based on its local frost dates. Confidence 82%.
When can I transplant lettuce outdoors in Osaka?
Transplant outdoors around early March (Mar 1–Mar 22) 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 lettuce to maturity outdoors.
The rule of thumb
Sow lettuce as soon as the soil is workable — it tolerates cool weather and light frost. 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.