When to plant sweet potato in Modesto
Sweet potato is frost-tender, so every date keys off Modesto's last spring frost of Jan 27.
Step 1 · Plant
Transplant outdoors
May 6 – May 27
Once frost risk has passed and nights stay mild.
Step 2 · Harvest
Harvest window
Aug 4 – Sep 3
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 120 d
Modesto's 310-day season leaves this much room.
Sweet potato on Modesto'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
JAN 27
DEC 3
Common questions
When will sweet potato be ready to harvest in Modesto?
Expect to harvest from around early August (Aug 4–Sep 3) in Modesto, based on its local frost dates. Confidence 78%.
When can I transplant sweet potato outdoors in Modesto?
Transplant outdoors around early May (May 6–May 27) in Modesto, based on its local frost dates. Confidence 84%.
How long is the growing season in Modesto?
Modesto has roughly 310 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 Modesto's frost dates.
Confidence 87/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.