When to plant cauliflower in Ottawa
Cauliflower is cold-hardy, so every date keys off Ottawa's frost dates of May 6.
Step 1 · Sow
Start seeds indoors
Mar 25 – Apr 15
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Apr 22 – May 13
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jun 21 – Jul 16
Picking runs until conditions turn against the crop.
Window
Days to maturity
60 – 85 d
Ottawa's 149-day season leaves this much room.
Cauliflower on Ottawa'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 6
OCT 2
Common questions
When will cauliflower be ready to harvest in Ottawa?
Expect to harvest from around late June (Jun 21–Jul 16) in Ottawa, based on its local frost dates. Confidence 76%.
When should I start cauliflower seeds indoors in Ottawa?
Start seeds indoors around late March (Mar 25–Apr 15) in Ottawa, based on its local frost dates. Confidence 80%.
When can I transplant cauliflower outdoors in Ottawa?
Transplant outdoors around late April (Apr 22–May 13) in Ottawa, based on its local frost dates. Confidence 84%.
How long is the growing season in Ottawa?
Ottawa has roughly 149 frost-free days, which is enough time to grow cauliflower to maturity outdoors.
The rule of thumb
Sow cauliflower as soon as the soil is workable — it tolerates cool weather and light frost. Every date on this page is derived from that rule and Ottawa's frost dates.
Confidence 84/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.