When to plant sweet potato in Missoula
Sweet potato is frost-tender, so every date keys off Missoula's last spring frost of May 15.
Step 1 · Plant
Transplant outdoors
Jul 8 – Jul 29
Once frost risk has passed and nights stay mild.
Step 2 · Harvest
Harvest window
Oct 6 – Nov 5
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 120 d
Missoula's 138-day season leaves this much room.
Sweet potato on Missoula'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
OCT 4
Common questions
When will sweet potato be ready to harvest in Missoula?
Expect to harvest from around early October (Oct 6–Nov 5) in Missoula, based on its local frost dates. Confidence 75%.
When can I transplant sweet potato outdoors in Missoula?
Transplant outdoors around early July (Jul 8–Jul 29) in Missoula, based on its local frost dates. Confidence 81%.
How long is the growing season in Missoula?
Missoula has roughly 138 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 Missoula's frost dates.
Confidence 83/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.