When to plant kale in Boise

Kale is cold-hardy, so every date keys off Boise's frost dates of May 2.
Step 1 · Sow
Start seeds indoors
Mar 21 – Apr 11
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Apr 11 – May 2
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jun 5 – Jun 25
Picking runs until conditions turn against the crop.
Step 4 · Second sowing
Autumn / second sowing
Jul 13 – Jul 27
A second window for a fall crop, timed to mature before the first frost.
Step 5 · Second harvest
Autumn crop harvest
Sep 13 – Oct 3
Maturity window for the second sowing.
Window
Days to maturity
55 – 75 d
Boise's 168-day season leaves this much room.
Kale on Boise'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
MAY 2
OCT 17

Common questions

When can I sow kale outdoors in Boise?

Direct-sow around mid April (Apr 11–May 2) in Boise, based on its local frost dates. Confidence 89%.

When will kale be ready to harvest in Boise?

Expect to harvest from around early June (Jun 5–Jun 25) in Boise, based on its local frost dates. Confidence 80%.

When should I start kale seeds indoors in Boise?

Start seeds indoors around late March (Mar 21–Apr 11) in Boise, based on its local frost dates. Confidence 85%.

When can I transplant kale outdoors in Boise?

Transplant outdoors around mid April (Apr 11–May 2) in Boise, based on its local frost dates. Confidence 89%.

Can I plant kale in autumn in Boise?

Yes — Boise supports a second, autumn sowing of kale around mid July (Jul 13–Jul 27), timed to mature before the first fall frost.

How long is the growing season in Boise?

Boise has roughly 168 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 Boise's frost dates.

Confidence 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.