When to plant summer squash / zucchini in Cologne
Summer squash / Zucchini is frost-tender, so every date keys off Cologne's last spring frost of Mar 26.
Step 1 · Sow
Start seeds indoors
Apr 4 – Apr 25
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Jun 2 – Jun 23
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jul 17 – Aug 1
Picking runs until conditions turn against the crop.
Window
Days to maturity
45 – 60 d
Cologne's 238-day season leaves this much room.
Summer squash / Zucchini on Cologne'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 26
NOV 17
Common questions
When can I sow summer squash / zucchini outdoors in Cologne?
Direct-sow around early June (Jun 2–Jun 23) in Cologne, based on its local frost dates. Confidence 86%.
When will summer squash / zucchini be ready to harvest in Cologne?
Expect to harvest from around mid July (Jul 17–Aug 1) in Cologne, based on its local frost dates. Confidence 80%.
When should I start summer squash / zucchini seeds indoors in Cologne?
Start seeds indoors around early April (Apr 4–Apr 25) in Cologne, based on its local frost dates. Confidence 85%.
When can I transplant summer squash / zucchini outdoors in Cologne?
Transplant outdoors around early June (Jun 2–Jun 23) in Cologne, based on its local frost dates. Confidence 86%.
How long is the growing season in Cologne?
Cologne has roughly 238 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 Cologne's frost dates.
Confidence 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.