Lewiston, Idaho is in USDA Hardiness Zones 7a and 7b.Click to see full answer. Herein, what planting zone is Idaho in?Idaho is in USDA plant hardiness zones 3-7. Idaho on average has approximately 145 days between the last and first frost. Using the planting schedules below will help you get the most out of your garden.Similarly, what planting zone is McCall Idaho? Zones 5a Then, what planting zone is Rathdrum Idaho? Rathdrum, Idaho is in USDA Hardiness Zones 6b.What planting zone is Meridian Idaho?Meridian, Idaho is in USDA Hardiness Zones 6b and 7a.