When to plant sweet potato in Sapporo
Sweet potato is frost-tender, so every date keys off Sapporo's last spring frost of May 5.
Step 1 · Plant
Transplant outdoors
May 26 – Jun 16
Once frost risk has passed and nights stay mild.
Step 2 · Harvest
Harvest window
Aug 24 – Sep 23
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 120 d
Sapporo's 173-day season leaves this much room.
Sweet potato on Sapporo'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 5
OCT 25
Common questions
When will sweet potato be ready to harvest in Sapporo?
Expect to harvest from around late August (Aug 24–Sep 23) in Sapporo, based on its local frost dates. Confidence 76%.
When can I transplant sweet potato outdoors in Sapporo?
Transplant outdoors around late May (May 26–Jun 16) in Sapporo, based on its local frost dates. Confidence 84%.
How long is the growing season in Sapporo?
Sapporo has roughly 173 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 Sapporo's frost dates.
Confidence 84/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.