I am a zone and a half warmer than you and I start cabbage collards brussel sprouts brocoli, califlower now till mid July in trays.Plants recieve afternoon shade, I set out the plants in Mid Aug to Mid Sept begin harvest Mid OCt till Jan. Carrots peas beets I plant in ground first week in Aug.I use agribon light weight cloth to cover seed bed after I plant and water daily till seeds are up about 10-14 days then remove cloth but keep up daily watering til well extablished. In Sept after it cools I sow lettuce spinach turnips mustard kale. But again I am much further south. I would suggest checking out Southern Exposure seeds website they have some great info on fall crops for mid atlantic states. Rodger