When to plant summer squash / zucchini in London
Summer squash / Zucchini is frost-tender, so every date keys off London's last spring frost of Apr 6.
Step 1 · Sow
Start seeds indoors
Apr 6 – Apr 27
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Jun 27 – Jul 18
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Aug 11 – Aug 26
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
London's 234-day season leaves this much room.
Summer squash / Zucchini on London'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
APR 6
NOV 16
Common questions
When can I sow summer squash / zucchini outdoors in London?
Direct-sow around late June (Jun 27–Jul 18) in London, based on its local frost dates. Confidence 80%.
When will summer squash / zucchini be ready to harvest in London?
Expect to harvest from around mid August (Aug 11–Aug 26) in London, based on its local frost dates. Confidence 74%.
When should I start summer squash / zucchini seeds indoors in London?
Start seeds indoors around early April (Apr 6–Apr 27) in London, based on its local frost dates. Confidence 78%.
When can I transplant summer squash / zucchini outdoors in London?
Transplant outdoors around late June (Jun 27–Jul 18) in London, based on its local frost dates. Confidence 80%.
How long is the growing season in London?
London has roughly 234 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 London's frost dates.
Confidence 82/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.