When to plant Onions in Wisconsin
In spring, from Mar 15 – Apr 10 in Caledonia to Apr 10 – May 1 in Wisconsin Rapids.
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 |
|---|---|
| Allouez | Apr 1 – May 1 |
| Appleton | Apr 1 – May 1 |
| Ashwaubenon | Apr 1 – May 1 |
| Baraboo | Apr 1 – May 1 |
| Beaver Dam | Apr 1 – May 1 |
| Bellevue | Apr 1 – May 1 |
| Beloit | Apr 1 – May 1 |
| Brookfield | Apr 1 – May 1 |
| Brown Deer | Apr 1 – May 1 |
| Burlington | Apr 1 – May 1 |
| Caledonia | Mar 15 – Apr 10 |
| Cedarburg | Mar 15 – Apr 10 |
| Chippewa Falls | Apr 10 – May 1 |
| Cudahy | Mar 15 – Apr 10 |
| De Pere | Apr 1 – May 1 |
| DeForest | Apr 1 – May 1 |
| Eau Claire | Mar 15 – Apr 10 |
| Elkhorn | Apr 1 – May 1 |
| Fitchburg | Apr 1 – May 1 |
| Fond du Lac | Apr 1 – May 1 |
| Fort Atkinson | Apr 1 – May 1 |
| Fox Crossing | Apr 1 – May 1 |
| Franklin | Apr 1 – May 1 |
| Germantown | Apr 10 – May 1 |
| Glendale | Apr 1 – May 1 |
| Grafton | Mar 15 – Apr 10 |
| Green Bay | Apr 10 – May 1 |
| Greendale | Apr 1 – May 1 |
| Greenfield | Apr 1 – May 1 |
| Greenville | Apr 1 – May 1 |
| Harrison | Apr 1 – May 1 |
| Hartford | Apr 10 – May 1 |
| Hartland | Apr 1 – May 1 |
| Hobart | Apr 1 – May 1 |
| Holmen | Mar 15 – Apr 10 |
| Howard | Apr 10 – May 1 |
| Hudson | Mar 15 – Apr 10 |
| Janesville | Apr 1 – May 1 |
| Kaukauna | Apr 1 – May 1 |
| Kenosha | Apr 1 – May 1 |
| La Crosse | Apr 1 – May 1 |
| Lisbon | Apr 1 – May 1 |
| Little Chute | Apr 1 – May 1 |
| Madison | Apr 1 – May 1 |
| Manitowoc | Apr 1 – May 1 |
| Marinette | Apr 1 – May 1 |
| Marshfield | Apr 1 – May 1 |
| Menasha | Apr 1 – May 1 |
| Menomonee Falls | Apr 10 – May 1 |
| Menomonie | Apr 10 – May 1 |
| Mequon | Apr 10 – May 1 |
| Middleton | Apr 1 – May 1 |
| Milwaukee | Apr 1 – May 1 |
| Monroe | Apr 1 – May 1 |
| Mount Pleasant | Mar 15 – Apr 10 |
| Muskego | Apr 1 – May 1 |
| Neenah | Apr 1 – May 1 |
| New Berlin | Apr 1 – May 1 |
| New Richmond | Mar 15 – Apr 10 |
| Oak Creek | Mar 15 – Apr 10 |
| Oconomowoc | Apr 1 – May 1 |
| Onalaska | Mar 15 – Apr 10 |
| Oregon | Apr 1 – May 1 |
| Oshkosh | Mar 15 – Apr 10 |
| Pewaukee | Apr 1 – May 1 |
| Platteville | Apr 1 – May 1 |
| Pleasant Prairie | Mar 15 – Apr 10 |
| Plover | Apr 1 – May 1 |
| Port Washington | Apr 1 – May 1 |
| Racine | Mar 15 – Apr 10 |
| Reedsburg | Apr 1 – May 1 |
| Richfield | Apr 1 – May 1 |
| River Falls | Apr 10 – May 1 |
| Salem Lakes | Apr 1 – May 1 |
| Sheboygan | Mar 15 – Apr 10 |
| Shorewood | Apr 1 – May 1 |
| South Milwaukee | Mar 15 – Apr 10 |
| Stevens Point | Apr 1 – May 1 |
| Stoughton | Apr 1 – May 1 |
| Suamico | Apr 10 – May 1 |
| Sun Prairie | Apr 1 – May 1 |
| Superior | Apr 10 – May 1 |
| Sussex | Apr 1 – May 1 |
| Two Rivers | Apr 1 – May 1 |
| Verona | Apr 1 – May 1 |
| Watertown | Apr 1 – May 1 |
| Waukesha | Apr 1 – May 1 |
| Waunakee | Apr 1 – May 1 |
| Waupun | Apr 1 – May 1 |
| Wausau | Apr 10 – May 1 |
| Wauwatosa | Apr 1 – May 1 |
| West Allis | Apr 1 – May 1 |
| West Bend | Apr 1 – May 1 |
| Weston | Apr 10 – May 1 |
| Whitefish Bay | Apr 1 – May 1 |
| Whitewater | Apr 1 – May 1 |
| Windsor | Apr 1 – May 1 |
| Wisconsin Rapids | Apr 10 – 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.