When to plant tomato in Seattle
Tomato is frost-tender, so every date keys off Seattle's last spring frost of Mar 17.
Step 1 · Sow
Start seeds indoors
Mar 2 – Mar 23
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Jun 6 – Jun 27
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Aug 5 – Aug 30
Picking runs until conditions turn against the crop.
Window
Days to maturity
60 – 85 d
Seattle's 237-day season leaves this much room.
Tomato 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 tomato be ready to harvest in Seattle?
Expect to harvest from around early August (Aug 5–Aug 30) in Seattle, based on its local frost dates. Confidence 75%.
When should I start tomato seeds indoors in Seattle?
Start seeds indoors around early March (Mar 2–Mar 23) in Seattle, based on its local frost dates. Confidence 79%.
When can I transplant tomato outdoors in Seattle?
Transplant outdoors around early June (Jun 6–Jun 27) in Seattle, based on its local frost dates. Confidence 81%.
How long is the growing season in Seattle?
Seattle has roughly 237 frost-free days, which is enough time to grow tomato to maturity outdoors.
The rule of thumb
Sow tomato 6–8 weeks before your last spring frost; plant out 2–3 weeks after it. 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.