When to plant winter squash / pumpkin in Bismarck
Winter squash / Pumpkin is frost-tender, so every date keys off Bismarck's last spring frost of May 15.
Step 1 · Sow
Start seeds indoors
May 7 – May 28
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Jun 7 – Jun 28
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Aug 31 – Oct 5
Picking runs until conditions turn against the crop.
Window
Days to maturity
85 – 120 d
Bismarck's 132-day season leaves this much room.
Winter squash / Pumpkin on Bismarck'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 15
SEP 25
Common questions
When can I sow winter squash / pumpkin outdoors in Bismarck?
Direct-sow around early June (Jun 7–Jun 28) in Bismarck, based on its local frost dates. Confidence 86%.
When will winter squash / pumpkin be ready to harvest in Bismarck?
Expect to harvest from around late August (Aug 31–Oct 5) in Bismarck, based on its local frost dates. Confidence 80%.
When should I start winter squash / pumpkin seeds indoors in Bismarck?
Start seeds indoors around early May (May 7–May 28) in Bismarck, based on its local frost dates. Confidence 85%.
When can I transplant winter squash / pumpkin outdoors in Bismarck?
Transplant outdoors around early June (Jun 7–Jun 28) in Bismarck, based on its local frost dates. Confidence 86%.
How long is the growing season in Bismarck?
Bismarck has roughly 132 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 Bismarck's frost dates.
Confidence 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.