Because Pennsylvania includes three U.S. Department of Agriculture plant hardiness zones and their subzones, the times for planting vegetables vary considerably from Philadelphia, which is in USDA zone 7a in the southeastern part of the state, to Bradford in USDA zone 5a in the northwest. The state’s coldest areas, in USDA zone 5a, are mostly concentrated in Warren and McKean counties. Because the requirements for gardening in USDA zone 5a differ from those in USDA zone 5b regions, the two subzones are listed separately. Always adapt seedlings started indoors gradually to the cooler and brighter conditions outdoors before you transplant them into a garden.
Hardy vegetables include those that can survive frosts, such as cabbage (Brassica oleracea, Capitata Group), broccoli (Brassica oleracea, Cymosa Group) and brussels sprouts (Brassica oleracea, Gemmifera Group