When to plant Onions in South Dakota
In spring, from Apr 1 – May 1 in Brandon to Apr 10 – May 1 in Watertown.
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 |
|---|---|
| Aberdeen | Apr 10 – May 1 |
| Box Elder | Apr 10 – May 1 |
| Brandon | Apr 1 – May 1 |
| Brookings | Apr 10 – May 1 |
| Harrisburg | Apr 1 – May 1 |
| Huron | Apr 10 – May 1 |
| Mitchell | Apr 1 – May 1 |
| Pierre | Apr 10 – May 1 |
| Rapid City | Apr 1 – May 1 |
| Sioux Falls | Apr 1 – May 1 |
| Spearfish | Apr 10 – May 1 |
| Vermillion | Apr 1 – May 1 |
| Watertown | Apr 10 – May 1 |
| Yankton | 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. The full USDA table for onion plants.