When to plant lettuce in Calgary
Lettuce is cold-hardy, so every date keys off Calgary's frost dates of May 23.
Step 1 · Sow
Start seeds indoors
Apr 25 – May 16
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
May 2 – May 23
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jun 16 – Jul 1
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
Calgary's 115-day season leaves this much room.
Lettuce on Calgary'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
MAY 23
SEP 15
Common questions
When can I sow lettuce outdoors in Calgary?
Direct-sow around late April (Apr 25–May 16) in Calgary, based on its local frost dates. Confidence 82%.
When will lettuce be ready to harvest in Calgary?
Expect to harvest from around mid June (Jun 16–Jul 1) in Calgary, based on its local frost dates. Confidence 74%.
When should I start lettuce seeds indoors in Calgary?
Start seeds indoors around late April (Apr 25–May 16) in Calgary, based on its local frost dates. Confidence 78%.
When can I transplant lettuce outdoors in Calgary?
Transplant outdoors around early May (May 2–May 23) in Calgary, based on its local frost dates. Confidence 82%.
How long is the growing season in Calgary?
Calgary has roughly 115 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 Calgary's frost dates.
Confidence 82/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.