State growing guide
Idaho Planting Guide
USDA Zone 5a/5b · Last frost May 5 · First frost Oct 8 · 156 days
Zone-specific planting calendar, major city frost dates, top crops, and Duke's tips for growing food in Idaho.
Frost Dates by City — Idaho
Average frost dates for major Idaho cities. Use these to calculate your indoor start dates and transplant windows.
| City | USDA Zone | Last Spring Frost | First Fall Frost | Tomato Transplant Window |
|---|---|---|---|---|
| Boise | 6b | Apr 20 | Oct 20 | ~2 wks after (Apr 20) |
| Pocatello | 5b | May 10 | Sep 25 | ~2 wks after (May 10) |
| Idaho Falls | 5a | May 20 | Sep 20 | ~2 wks after (May 20) |
| Twin Falls | 6a | Apr 28 | Oct 12 | ~2 wks after (Apr 28) |
| Coeur d'Alene | 6a | Apr 26 | Oct 8 | ~2 wks after (Apr 26) |
Average dates based on 30-year NOAA climate normals. Individual years may vary ±2 weeks. Use the Zone Lookup Tool for ZIP-specific dates.
Duke's Top Tips for Idaho Gardeners
- Boise (Zone 6b) has the best growing conditions in Idaho
- Idaho Falls gardeners need short-season varieties — fewer than 80 days to maturity
- Potatoes are king in Idaho — plant when soil hits 45°F in late April
- Boise's Snake River Plain has warm summers and mild winters relative to elevation
Common Challenges in Idaho
- ⚠ Short growing season in most of Idaho (120–160 days)
- ⚠ Late spring and early fall frosts catch gardeners off guard
- ⚠ Water rights and irrigation are critical — drip irrigation strongly recommended
Best Crops for Idaho
Get exact dates for your ZIP code in Idaho
City averages are a starting point. Your actual microclimate matters — enter your ZIP for precise frost dates.
Frequently Asked Questions — Idaho Gardening
What zone is Idaho?
Idaho ranges from Zone 3 in the high wilderness to Zone 7a in the Snake River Canyon. Boise is Zone 6b, Pocatello is Zone 5b, and Idaho Falls is Zone 5a.
When to plant tomatoes in Idaho?
In Boise: transplant early to mid-May. In Pocatello and Idaho Falls: wait until late May. Use season extenders (Wall O' Waters, hoop tunnels) to add 3–4 weeks to your season.