When to plant melon (cantaloupe/watermelon) in Portland

Melon (cantaloupe/watermelon) is frost-tender, so every date keys off Portland's last spring frost of May 1.
Step 1 · Sow
Start seeds indoors
Apr 20 – May 11
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Jul 24 – Aug 14
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Oct 7 – Nov 1
Picking runs until conditions turn against the crop.
Window
Days to maturity
75 – 100 d
Portland's 165-day season leaves this much room.
Melon (cantaloupe/watermelon) on Portland'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
MAY 1
OCT 10

Common questions

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

Direct-sow around late July (Jul 24–Aug 14) in Portland, based on its local frost dates. Confidence 86%.

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

Expect to harvest from around early October (Oct 7–Nov 1) in Portland, based on its local frost dates. Confidence 80%.

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

Start seeds indoors around mid April (Apr 20–May 11) in Portland, based on its local frost dates. Confidence 85%.

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

Transplant outdoors around late July (Jul 24–Aug 14) in Portland, based on its local frost dates. Confidence 86%.

How long is the growing season in Portland?

Portland has roughly 165 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 Portland's frost dates.

Confidence 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.