When to plant sweet potato in Bismarck
Sweet potato is frost-tender, so every date keys off Bismarck's last spring frost of May 15.
Step 1 · Plant
Transplant outdoors
Jun 22 – Jul 13
Once frost risk has passed and nights stay mild.
Step 2 · Harvest
Harvest window
Sep 20 – Oct 20
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 120 d
Bismarck's 132-day season leaves this much room.
Sweet potato 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
MAY 15
SEP 25
Common questions
When will sweet potato be ready to harvest in Bismarck?
Expect to harvest from around mid September (Sep 20–Oct 20) in Bismarck, based on its local frost dates. Confidence 80%.
When can I transplant sweet potato outdoors in Bismarck?
Transplant outdoors around late June (Jun 22–Jul 13) 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 sweet potato to maturity outdoors.
The rule of thumb
Sow sweet potato 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.