Idaho · zones 5b–7b
When to plant basil in Idaho.
Sow or transplant between Jun 1 to Aug 17 in a typical year, keyed to Idaho's median last frost around May 11. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Basil dates for a typical Idaho season.
1 · Start indoors
Apr 20 to Jul 6
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
Jun 1 to Aug 17
Keyed to the ~May 11 last frost. Sow 0.25" deep, 8" apart.
Harvest
~40 days later
~0.5 lb per plant over ~12 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.