When to plant summer squash / zucchini in Charleston

Summer squash / Zucchini is frost-tender, so every date keys off Charleston's last spring frost of Feb 8.
Step 1 · Sow
Start seeds indoors
Feb 18 – Mar 11
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Mar 30 – Apr 20
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
May 14 – May 29
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
Charleston's 310-day season leaves this much room.
Summer squash / Zucchini on Charleston'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
FEB 8
DEC 15

Common questions

When can I sow summer squash / zucchini outdoors in Charleston?

Direct-sow around late March (Mar 30–Apr 20) in Charleston, based on its local frost dates. Confidence 86%.

When will summer squash / zucchini be ready to harvest in Charleston?

Expect to harvest from around mid May (May 14–May 29) in Charleston, based on its local frost dates. Confidence 80%.

When should I start summer squash / zucchini seeds indoors in Charleston?

Start seeds indoors around mid February (Feb 18–Mar 11) in Charleston, based on its local frost dates. Confidence 85%.

When can I transplant summer squash / zucchini outdoors in Charleston?

Transplant outdoors around late March (Mar 30–Apr 20) in Charleston, based on its local frost dates. Confidence 86%.

How long is the growing season in Charleston?

Charleston has roughly 310 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 Charleston's frost dates.

Confidence 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.