When to plant cabbage in Ottawa
Cabbage is cold-hardy, so every date keys off Ottawa's frost dates of Apr 29.
Step 1 · Sow
Start seeds indoors
Mar 18 – Apr 8
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Apr 23 – May 14
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jul 2 – Aug 1
Picking runs until conditions turn against the crop.
Step 4 · Second sowing
Autumn / second sowing
Jun 9 – Jun 23
A second window for a fall crop, timed to mature before the first frost.
Step 5 · Second harvest
Autumn crop harvest
Aug 25 – Sep 24
Maturity window for the second sowing.
Window
Days to maturity
70 – 100 d
Ottawa's 161-day season leaves this much room.
Cabbage 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
APR 29
OCT 8
Common questions
When will cabbage be ready to harvest in Ottawa?
Expect to harvest from around early July (Jul 2–Aug 1) in Ottawa, based on its local frost dates. Confidence 80%.
When should I start cabbage seeds indoors in Ottawa?
Start seeds indoors around mid March (Mar 18–Apr 8) in Ottawa, based on its local frost dates. Confidence 85%.
When can I transplant cabbage outdoors in Ottawa?
Transplant outdoors around late April (Apr 23–May 14) in Ottawa, based on its local frost dates. Confidence 86%.
Can I plant cabbage in autumn in Ottawa?
Yes — Ottawa supports a second, autumn sowing of cabbage around early June (Jun 9–Jun 23), timed to mature before the first fall frost.
How long is the growing season in Ottawa?
Ottawa has roughly 161 frost-free days, which is enough time to grow cabbage to maturity outdoors.
The rule of thumb
Sow cabbage 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 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.