When to plant winter squash / pumpkin in San Jose
Winter squash / Pumpkin is frost-tender, so every date keys off San Jose's last spring frost of Feb 12.
Step 1 · Sow
Start seeds indoors
Feb 17 – Mar 10
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
May 10 – May 31
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Aug 3 – Sep 7
Picking runs until conditions turn against the crop.
Window
Days to maturity
85 – 120 d
San Jose's 294-day season leaves this much room.
Winter squash / Pumpkin on San Jose'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
HARVEST
FEB 12
DEC 3
Common questions
When can I sow winter squash / pumpkin outdoors in San Jose?
Direct-sow around early May (May 10–May 31) in San Jose, based on its local frost dates. Confidence 80%.
When will winter squash / pumpkin be ready to harvest in San Jose?
Expect to harvest from around early August (Aug 3–Sep 7) in San Jose, based on its local frost dates. Confidence 74%.
When should I start winter squash / pumpkin seeds indoors in San Jose?
Start seeds indoors around mid February (Feb 17–Mar 10) in San Jose, based on its local frost dates. Confidence 78%.
When can I transplant winter squash / pumpkin outdoors in San Jose?
Transplant outdoors around early May (May 10–May 31) in San Jose, based on its local frost dates. Confidence 80%.
How long is the growing season in San Jose?
San Jose has roughly 294 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 San Jose's frost dates.
Confidence 82/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.