When to plant summer squash / zucchini in Toronto
Summer squash / Zucchini is frost-tender, so every date keys off Toronto's last spring frost of May 9.
Step 1 · Sow
Start seeds indoors
Apr 25 – May 16
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
May 16 – Jun 6
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jun 30 – Jul 15
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
Toronto's 150-day season leaves this much room.
Summer squash / Zucchini on Toronto'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
MAY 9
OCT 6
Common questions
When can I sow summer squash / zucchini outdoors in Toronto?
Direct-sow around mid May (May 16–Jun 6) in Toronto, based on its local frost dates. Confidence 88%.
When will summer squash / zucchini be ready to harvest in Toronto?
Expect to harvest from around late June (Jun 30–Jul 15) in Toronto, based on its local frost dates. Confidence 79%.
When should I start summer squash / zucchini seeds indoors in Toronto?
Start seeds indoors around late April (Apr 25–May 16) in Toronto, based on its local frost dates. Confidence 84%.
When can I transplant summer squash / zucchini outdoors in Toronto?
Transplant outdoors around mid May (May 16–Jun 6) in Toronto, based on its local frost dates. Confidence 88%.
How long is the growing season in Toronto?
Toronto has roughly 150 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 Toronto's frost dates.
Confidence 88/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.