When to plant lettuce in Osaka

Lettuce is cold-hardy, so every date keys off Osaka's frost dates of Apr 10.
Step 1 · Sow
Start seeds indoors
Mar 13 – Apr 3
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Mar 20 – Apr 10
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
May 4 – May 19
Picking runs until conditions turn against the crop.
Step 4 · Second sowing
Autumn / second sowing
Aug 26 – Sep 9
A second window for a fall crop, timed to mature before the first frost.
Step 5 · Second harvest
Autumn crop harvest
Oct 17 – Nov 1
Maturity window for the second sowing.
Window
Days to maturity
45 – 60 d
Osaka's 228-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
APR 10
NOV 22

Common questions

When can I sow lettuce outdoors in Osaka?

Direct-sow around mid March (Mar 13–Apr 3) in Osaka, based on its local frost dates. Confidence 45%.

When will lettuce be ready to harvest in Osaka?

Expect to harvest from around early May (May 4–May 19) in Osaka, based on its local frost dates. Confidence 40%.

When should I start lettuce seeds indoors in Osaka?

Start seeds indoors around mid March (Mar 13–Apr 3) in Osaka, based on its local frost dates. Confidence 43%.

When can I transplant lettuce outdoors in Osaka?

Transplant outdoors around mid March (Mar 20–Apr 10) in Osaka, based on its local frost dates. Confidence 45%.

Can I plant lettuce in autumn in Osaka?

Yes — Osaka supports a second, autumn sowing of lettuce around late August (Aug 26–Sep 9), timed to mature before the first fall frost.

How long is the growing season in Osaka?

Osaka has roughly 228 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 45/100 · Curated · based on NASA POWER (modeled) 1991–2020 · frost dates are probabilities, not guarantees.