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 Mar 1.
Step 1 · Sow
Start seeds indoors
Feb 24 – Mar 17
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Jul 30 – Aug 20
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Oct 13 – Nov 7
Picking runs until conditions turn against the crop.
Window
Days to maturity
75 – 100 d
Portland's 266-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
MAR 1
NOV 22

Common questions

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

Direct-sow around late July (Jul 30–Aug 20) in Portland, based on its local frost dates. Confidence 85%.

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

Expect to harvest from around mid October (Oct 13–Nov 7) in Portland, based on its local frost dates. Confidence 79%.

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

Start seeds indoors around late February (Feb 24–Mar 17) in Portland, based on its local frost dates. Confidence 84%.

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

Transplant outdoors around late July (Jul 30–Aug 20) in Portland, based on its local frost dates. Confidence 85%.

How long is the growing season in Portland?

Portland has roughly 266 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 88/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.