When to plant winter squash / pumpkin in Portland
Winter squash / Pumpkin 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
Jun 11 – Jul 2
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Sep 4 – Oct 9
Picking runs until conditions turn against the crop.
Window
Days to maturity
85 – 120 d
Portland's 165-day season leaves this much room.
Winter squash / Pumpkin 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
FROST
FROST
HARVEST
MAY 1
OCT 10
Common questions
When can I sow winter squash / pumpkin outdoors in Portland?
Direct-sow around mid June (Jun 11–Jul 2) in Portland, based on its local frost dates. Confidence 86%.
When will winter squash / pumpkin be ready to harvest in Portland?
Expect to harvest from around early September (Sep 4–Oct 9) in Portland, based on its local frost dates. Confidence 80%.
When should I start winter squash / pumpkin 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 winter squash / pumpkin outdoors in Portland?
Transplant outdoors around mid June (Jun 11–Jul 2) 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 winter squash / pumpkin to maturity outdoors.
The rule of thumb
Sow winter squash / pumpkin 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.