Idaho · zones 5b–7b
When to plant lettuce in Idaho.
Sow between Apr 3 to May 18 in a typical year, keyed to Idaho's median last frost around May 11. A second, fall sowing fits Jul 15 to Sep 13. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Lettuce dates for a typical Idaho season.
Direct sow
Apr 3 to May 18
Keyed to the ~May 11 last frost. Sow 0.25" deep, 6" apart.
Fall round
Jul 15 to Sep 13
Counted back from the ~Sep 28 first frost.
Harvest
~45 days later
~0.4 lb per plant over ~1 weeks.
Idaho spans more than one climate: Zone 6 is the most common zone, but the state runs 5b to 7b. 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.