When to plant melon (cantaloupe/watermelon) in Seattle

Melon (cantaloupe/watermelon) is frost-tender, so every date keys off Seattle's last spring frost of Mar 17.
Step 1 · Sow
Start seeds indoors
Mar 23 – Apr 13
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Aug 9 – Aug 30
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Oct 23 – Nov 17
Picking runs until conditions turn against the crop.
Window
Days to maturity
75 – 100 d
Seattle's 237-day season leaves this much room.
Melon (cantaloupe/watermelon) 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
MAR 17
NOV 13

Common questions

When can I sow melon (cantaloupe/watermelon) outdoors in Seattle?

Direct-sow around early August (Aug 9–Aug 30) in Seattle, based on its local frost dates. Confidence 81%.

When will melon (cantaloupe/watermelon) be ready to harvest in Seattle?

Expect to harvest from around late October (Oct 23–Nov 17) in Seattle, based on its local frost dates. Confidence 75%.

When should I start melon (cantaloupe/watermelon) seeds indoors in Seattle?

Start seeds indoors around late March (Mar 23–Apr 13) in Seattle, based on its local frost dates. Confidence 79%.

When can I transplant melon (cantaloupe/watermelon) outdoors in Seattle?

Transplant outdoors around early August (Aug 9–Aug 30) 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 melon (cantaloupe/watermelon) to maturity outdoors.

The rule of thumb

Sow melon (cantaloupe/watermelon) 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.