Idaho Planting Calendar

Frost dates, growing zones, and planting dates for Idaho gardeners.

Zone 3b Zone 4a Zone 4b Zone 5a Zone 5b Zone 6a Zone 6b Zone 7a

The Short Answer

Idaho spans USDA zones 3b through 7a, which means planting dates vary significantly across the state. Northern Idaho has an average last frost around May 5 - May 25, while Eastern Idaho sees its last frost around May 20 - Jun 10. Use our homepage tool with your zip code for dates specific to your exact location.

Idaho Frost Dates by Region

Arid climate. Low humidity. Hot days and cool nights. Irrigation essential. Short season at higher elevations.

Region	Zones	Last Frost (Spring)	First Frost (Fall)
Northern Idaho	5a, 5b, 6a	May 5 - May 25	Sep 15 - Oct 5
Boise Area	6b, 7a	Apr 20 - May 5	Oct 5 - Oct 20
Eastern Idaho	3b, 4a, 4b, 5a	May 20 - Jun 10	Sep 1 - Sep 20

Soil & Growing Conditions

Volcanic ash soils in south — excellent for gardening. Rocky soils in mountains. Alkaline in many areas.

What to Plant in Idaho

Idaho's short growing season rewards strategic planning. Cold-hardy crops are your strength, and warm-season crops need indoor starting. These are the best performers for Idaho's climate:

Top Picks for Idaho

Kale Garlic Potatoes Peas Carrots Lettuce Broccoli Beets Radishes Spinach Beans (Green/Snap)Cabbage Daffodils

Worth the Effort

With indoor starting and season extension, Idaho gardeners also grow excellent tomatoes, peppers, cucumbers, and sunflowers. The long summer daylight hours drive faster growth than you'd expect:

Tomatoes Peppers Cucumbers Squash (Summer)Basil Sunflowers Zinnias Corn (Sweet)

Browse all 100 plants — or enter your zip code for personalized planting dates.

Neighboring States

Gardeners near state borders may find useful information in neighboring state guides:

Alabama Alaska Arizona Arkansas California Colorado Connecticut Delaware Florida Georgia Hawaii Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota Tennessee Texas Utah Vermont Virginia Washington West Virginia Wisconsin Wyoming

Note: Frost dates are based on NOAA 30-year Climate Normals and represent historical averages. Actual frost dates can vary significantly year to year. Zone data is from the USDA Plant Hardiness Zone Map.

Last reviewed: March 29, 2026