When to plant summer squash / zucchini in San Jose
Summer squash / Zucchini is frost-tender, so every date keys off San Jose's last spring frost of Feb 12.
Step 1 · Sow
Start seeds indoors
Feb 24 – Mar 17
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
Jun 24 – Jul 9
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
San Jose's 294-day season leaves this much room.
Summer squash / Zucchini 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
FEB 12
DEC 3
Common questions
When can I sow summer squash / zucchini 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 summer squash / zucchini be ready to harvest in San Jose?
Expect to harvest from around late June (Jun 24–Jul 9) in San Jose, based on its local frost dates. Confidence 74%.
When should I start summer squash / zucchini seeds indoors in San Jose?
Start seeds indoors around late February (Feb 24–Mar 17) in San Jose, based on its local frost dates. Confidence 78%.
When can I transplant summer squash / zucchini 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 summer squash / zucchini to maturity outdoors.
The rule of thumb
Sow summer squash / zucchini 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.