When to plant Onions in Idaho
In spring, from Mar 1 – Apr 1 in Lewiston to Apr 20 – May 15 in Garden City.
In fall: USDA's 1967 table lists onion plants as generally spring-planted in every place here. Newer advice from your state's extension service may differ.
Dates are for setting out plants. USDA's earliest safe spring and latest safe fall planting dates, matched to each place's average frost dates.
| Place | Spring |
|---|---|
| Ammon | Apr 10 – May 1 |
| Blackfoot | Apr 1 – May 1 |
| Boise City | Mar 15 – Apr 10 |
| Burley | Apr 10 – May 1 |
| Caldwell | Apr 1 – May 1 |
| Chubbuck | Apr 20 – May 15 |
| Coeur d'Alene | Mar 15 – Apr 10 |
| Eagle | Apr 1 – May 1 |
| Garden City | Apr 20 – May 15 |
| Hayden | Mar 15 – Apr 10 |
| Idaho Falls | Apr 10 – May 1 |
| Jerome | Apr 1 – May 1 |
| Kuna | Mar 15 – Apr 10 |
| Lewiston | Mar 1 – Apr 1 |
| Meridian | Mar 15 – Apr 10 |
| Middleton | Apr 1 – May 1 |
| Moscow | Apr 1 – May 1 |
| Mountain Home | Apr 1 – May 1 |
| Nampa | Apr 1 – May 1 |
| Pocatello | Apr 1 – May 1 |
| Post Falls | Mar 15 – Apr 10 |
| Rathdrum | Mar 15 – Apr 10 |
| Rexburg | Apr 10 – May 1 |
| Sandpoint | Apr 10 – May 1 |
| Star | Apr 1 – May 1 |
| Twin Falls | Apr 1 – May 1 |
Planting dates: USDA Home and Garden Bulletin No. 9 (1967), tables 4 and 5. Frost dates: NOAA U.S. Climate Normals 1991–2020. “—” means the place's frost date is outside the table. The full USDA table for onion plants.