When to plant summer squash / zucchini in Columbia
Summer squash / Zucchini is frost-tender, so every date keys off Columbia's last spring frost of Mar 11.
Step 1 · Sow
Start seeds indoors
Mar 17 – Apr 7
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Apr 7 – Apr 28
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
May 22 – Jun 6
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
Columbia's 248-day season leaves this much room.
Summer squash / Zucchini on Columbia'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
MAR 11
NOV 17
Common questions
When can I sow summer squash / zucchini outdoors in Columbia?
Direct-sow around early April (Apr 7–Apr 28) in Columbia, based on its local frost dates. Confidence 88%.
When will summer squash / zucchini be ready to harvest in Columbia?
Expect to harvest from around late May (May 22–Jun 6) in Columbia, based on its local frost dates. Confidence 79%.
When should I start summer squash / zucchini seeds indoors in Columbia?
Start seeds indoors around mid March (Mar 17–Apr 7) in Columbia, based on its local frost dates. Confidence 84%.
When can I transplant summer squash / zucchini outdoors in Columbia?
Transplant outdoors around early April (Apr 7–Apr 28) in Columbia, based on its local frost dates. Confidence 88%.
How long is the growing season in Columbia?
Columbia has roughly 248 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 Columbia's frost dates.
Confidence 88/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.