When to plant Onions in Pennsylvania
In spring, from Feb 15 – Mar 15 in Chester to Apr 10 – May 1 in St. Marys.
In fall, from Sept 1 – Oct 15 in Darby to Oct 1 – Dec 31 in Philadelphia.
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 | Fall |
|---|---|---|
| Allentown | Mar 15 – Apr 10 | Spring-planted |
| Altoona | Mar 15 – Apr 10 | Spring-planted |
| Baldwin | Mar 15 – Apr 10 | Not listed |
| Berwick | Apr 1 – May 1 | Spring-planted |
| Bethel Park | Mar 15 – Apr 10 | Not listed |
| Bethlehem | Mar 15 – Apr 10 | Spring-planted |
| Bloomsburg | Apr 1 – May 1 | Spring-planted |
| Butler | Apr 10 – May 1 | Spring-planted |
| Carlisle | Mar 15 – Apr 10 | Spring-planted |
| Chambersburg | Mar 15 – Apr 10 | Spring-planted |
| Chester | Feb 15 – Mar 15 | Oct 1 – Dec 31Now |
| Coatesville | Mar 15 – Apr 10 | Spring-planted |
| Columbia | Apr 1 – May 1 | Spring-planted |
| Darby | Feb 15 – Mar 15 | Sept 1 – Oct 15 |
| Dunmore | Mar 15 – Apr 10 | Spring-planted |
| Easton | Mar 15 – Apr 10 | Spring-planted |
| Elizabethtown | Mar 1 – Apr 1 | Not listed |
| Emmaus | Mar 15 – Apr 10 | Spring-planted |
| Ephrata | Mar 15 – Apr 10 | Spring-planted |
| Erie | Apr 1 – May 1 | Not listed |
| Franklin Park | Mar 15 – Apr 10 | Not listed |
| Greensburg | Apr 1 – May 1 | Spring-planted |
| Hanover | Mar 15 – Apr 10 | Spring-planted |
| Harrisburg | Mar 1 – Apr 1 | Spring-planted |
| Hazleton | Apr 1 – May 1 | Spring-planted |
| Hermitage | Apr 10 – May 1 | Spring-planted |
| Indiana | Apr 10 – May 1 | Spring-planted |
| Jefferson Hills | Mar 15 – Apr 10 | Not listed |
| Johnstown | Apr 1 – May 1 | Spring-planted |
| Kingston | Mar 15 – Apr 10 | Spring-planted |
| Lancaster | Mar 15 – Apr 10 | Spring-planted |
| Lansdale | Mar 1 – Apr 1 | Not listed |
| Lansdowne | Feb 15 – Mar 15 | Sept 1 – Oct 15 |
| Lebanon | Mar 15 – Apr 10 | Spring-planted |
| Lower Burrell | Mar 15 – Apr 10 | Not listed |
| McKeesport | Apr 1 – May 1 | Spring-planted |
| Meadville | Apr 1 – May 1 | Spring-planted |
| Mechanicsburg | Mar 1 – Apr 1 | Not listed |
| Monroeville | Mar 15 – Apr 10 | Spring-planted |
| Munhall | Mar 1 – Apr 1 | Sept 1 – Oct 15 |
| Murrysville | Mar 15 – Apr 10 | Spring-planted |
| Nanticoke | Apr 10 – May 1 | Spring-planted |
| New Castle | Apr 1 – May 1 | Spring-planted |
| New Kensington | Mar 15 – Apr 10 | Not listed |
| Norristown | Mar 1 – Apr 1 | Not listed |
| Northampton | Mar 15 – Apr 10 | Spring-planted |
| Philadelphia | Feb 15 – Mar 15 | Oct 1 – Dec 31Now |
| Phoenixville | Mar 15 – Apr 10 | Not listed |
| Pittsburgh | Mar 15 – Apr 10 | Not listed |
| Plum | Mar 15 – Apr 10 | Not listed |
| Pottstown | Mar 15 – Apr 10 | Spring-planted |
| Pottsville | Apr 1 – May 1 | Spring-planted |
| Reading | Mar 1 – Apr 1 | Not listed |
| Scranton | Mar 15 – Apr 10 | Spring-planted |
| Sharon | Apr 1 – May 1 | Spring-planted |
| St. Marys | Apr 10 – May 1 | Spring-planted |
| State College | Mar 15 – Apr 10 | Not listed |
| Washington | Mar 15 – Apr 10 | Spring-planted |
| Waynesboro | Mar 15 – Apr 10 | Spring-planted |
| West Chester | Apr 1 – May 1 | Spring-planted |
| West Mifflin | Mar 15 – Apr 10 | Not listed |
| Whitehall | Mar 15 – Apr 10 | Not listed |
| Wilkes-Barre | Mar 15 – Apr 10 | Spring-planted |
| Wilkinsburg | Mar 1 – Apr 1 | Sept 1 – Oct 15 |
| Williamsport | Mar 15 – Apr 10 | Spring-planted |
| Wyomissing | Mar 1 – Apr 1 | Not listed |
| Yeadon | Feb 15 – Mar 15 | Sept 1 – Oct 15 |
| York | Apr 1 – May 1 | Spring-planted |
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.