Montana · zones 4a–5b
When to plant cucumbers in Montana.
Sow between May 22 to Aug 21 in a typical year, keyed to Montana's median last frost around May 15. A second, fall sowing fits May 23 to Jun 23. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Cucumbers dates for a typical Montana season.
Direct sow
May 22 to Aug 21
Keyed to the ~May 15 last frost. Sow 1" deep, 12" apart.
Fall round
May 23 to Jun 23
Counted back from the ~Sep 23 first frost.
Harvest
~60 days later
~5 lb per plant over ~5 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.