When to plant leek in Calgary
Leek is cold-hardy, so every date keys off Calgary's frost dates of May 23.
Step 1 · Sow
Start seeds indoors
Mar 14 – Apr 4
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
May 9 – May 30
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Aug 17 – Sep 6
Picking runs until conditions turn against the crop.
Window
Days to maturity
100 – 120 d
Calgary's 115-day season leaves this much room.
Leek 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 will leek be ready to harvest in Calgary?
Expect to harvest from around mid August (Aug 17–Sep 6) in Calgary, based on its local frost dates. Confidence 74%.
When should I start leek seeds indoors in Calgary?
Start seeds indoors around mid March (Mar 14–Apr 4) in Calgary, based on its local frost dates. Confidence 78%.
When can I transplant leek outdoors in Calgary?
Transplant outdoors around early May (May 9–May 30) 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 leek to maturity outdoors.
The rule of thumb
Sow leek 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.