Montana · zones 4a–5b
When to plant garlic in Montana.
Montana's window for garlic runs on the fall side of the season. A second, fall sowing fits Aug 23 to Oct 8. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Garlic dates for a typical Montana season.
Fall round
Aug 23 to Oct 8
Counted back from the ~Sep 23 first frost.
Harvest
~240 days later
~0.2 lb per plant over ~1 weeks.
Montana spans more than one climate: Zone 4 is the most common zone, but the state runs 4a to 5b. That's why the planner works from your ZIP code's frost dates, not your zone — mountain and coastal gardens in the same state can be three weeks apart.