When to plant Kale in Montana

In spring, from Apr 1 – 20 in Billings to May 15 – June 1 in Butte-Silver Bow (balance).

In fall, from May 15 – June 15 in Butte-Silver Bow (balance) to July 1 – Aug 1 in Billings.

USDA's earliest safe spring and latest safe fall planting dates, matched to each place's average frost dates.

Kale planting dates by place in Montana
PlaceSpringFall
BelgradeMay 1 – 30June 1 – July 1
BillingsApr 1 – 20July 1 – Aug 1
BozemanMay 1 – 30June 1 – July 1
Butte-Silver Bow (balance)May 15 – June 1May 15 – June 15
Great FallsApr 10 – May 1June 15 – July 15
HelenaApr 10 – May 1June 15 – July 15
KalispellMay 1 – 30May 15 – June 15
MissoulaApr 10 – May 1June 15 – July 15

Planting dates: USDA Home and Garden Bulletin No. 9 (1967), tables 4 and 5. Frost dates: NOAA U.S. Climate Normals 1991–2020. “—” means the place's frost date is outside the table. The full USDA table for kale.