When to plant lettuce in San Bernardino

Lettuce is cold-hardy, so every date keys off San Bernardino's frost dates of Feb 23.
Step 1 · Sow
Start seeds indoors
Jan 26 – Feb 16
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Dec 26 – Jan 16
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Feb 9 – Feb 24
Picking runs until conditions turn against the crop.
Step 4 · Second sowing
Autumn / second sowing
Sep 5 – Sep 19
A second window for a fall crop, timed to mature before the first frost.
Step 5 · Second harvest
Autumn crop harvest
Oct 27 – Nov 11
Maturity window for the second sowing.
Window
Days to maturity
45 – 60 d
San Bernardino's 284-day season leaves this much room.
Lettuce on San Bernardino'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
FEB 23
DEC 9

Common questions

When can I sow lettuce outdoors in San Bernardino?

Direct-sow around late December (Dec 26–Jan 16) in San Bernardino, based on its local frost dates. Confidence 76%.

When will lettuce be ready to harvest in San Bernardino?

Expect to harvest from around early February (Feb 9–Feb 24) in San Bernardino, based on its local frost dates. Confidence 70%.

When should I start lettuce seeds indoors in San Bernardino?

Start seeds indoors around late January (Jan 26–Feb 16) in San Bernardino, based on its local frost dates. Confidence 74%.

When can I transplant lettuce outdoors in San Bernardino?

Transplant outdoors around late December (Dec 26–Jan 16) in San Bernardino, based on its local frost dates. Confidence 76%.

Can I plant lettuce in autumn in San Bernardino?

Yes — San Bernardino supports a second, autumn sowing of lettuce around early September (Sep 5–Sep 19), timed to mature before the first fall frost.

How long is the growing season in San Bernardino?

San Bernardino has roughly 284 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 San Bernardino's frost dates.

Confidence 78/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.