When to plant leek in Cologne
Leek is cold-hardy, so every date keys off Cologne's frost dates of Apr 20.
Step 1 · Sow
Start seeds indoors
Feb 9 – Mar 2
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Apr 6 – Apr 27
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jul 15 – Aug 4
Picking runs until conditions turn against the crop.
Window
Days to maturity
100 – 120 d
Cologne's 185-day season leaves this much room.
Leek on Cologne'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
APR 20
OCT 22
Common questions
When will leek be ready to harvest in Cologne?
Expect to harvest from around mid July (Jul 15–Aug 4) in Cologne, based on its local frost dates. Confidence 74%.
When should I start leek seeds indoors in Cologne?
Start seeds indoors around early February (Feb 9–Mar 2) in Cologne, based on its local frost dates. Confidence 78%.
When can I transplant leek outdoors in Cologne?
Transplant outdoors around early April (Apr 6–Apr 27) in Cologne, based on its local frost dates. Confidence 82%.
How long is the growing season in Cologne?
Cologne has roughly 185 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 Cologne's frost dates.
Confidence 82/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.