When to plant kale in Ottawa

Kale 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
Jun 17 – Jul 7
Picking runs until conditions turn against the crop.
Step 4 · Second sowing
Autumn / second sowing
Jul 4 – Jul 18
A second window for a fall crop, timed to mature before the first frost.
Step 5 · Second harvest
Autumn crop harvest
Sep 4 – Sep 24
Maturity window for the second sowing.
Window
Days to maturity
55 – 75 d
Ottawa's 161-day season leaves this much room.
Kale 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
APR 29
OCT 8

Common questions

When can I sow kale outdoors in Ottawa?

Direct-sow around late April (Apr 23–May 14) in Ottawa, based on its local frost dates. Confidence 86%.

When will kale be ready to harvest in Ottawa?

Expect to harvest from around mid June (Jun 17–Jul 7) in Ottawa, based on its local frost dates. Confidence 80%.

When should I start kale 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 kale 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 kale in autumn in Ottawa?

Yes — Ottawa supports a second, autumn sowing of kale around early July (Jul 4–Jul 18), 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 kale to maturity outdoors.

The rule of thumb

Sow kale 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.