When to plant leek in Seattle
Leek is cold-hardy, so every date keys off Seattle's frost dates of Mar 17.
Step 1 · Sow
Start seeds indoors
Jan 6 – Jan 27
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Mar 3 – Mar 24
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jun 11 – Jul 1
Picking runs until conditions turn against the crop.
Window
Days to maturity
100 – 120 d
Seattle's 237-day season leaves this much room.
Leek on Seattle'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
MAR 17
NOV 13
Common questions
When will leek be ready to harvest in Seattle?
Expect to harvest from around mid June (Jun 11–Jul 1) in Seattle, based on its local frost dates. Confidence 75%.
When should I start leek seeds indoors in Seattle?
Start seeds indoors around early January (Jan 6–Jan 27) in Seattle, based on its local frost dates. Confidence 79%.
When can I transplant leek outdoors in Seattle?
Transplant outdoors around early March (Mar 3–Mar 24) in Seattle, based on its local frost dates. Confidence 83%.
How long is the growing season in Seattle?
Seattle has roughly 237 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 Seattle's frost dates.
Confidence 83/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.