Her method of fall-seeding collards for midwinter transplants can be tricky. If the plants are too small, they won't survive the cold. According to Doug Sanders, North Carolina State University Extension horticulturist, plants with more than six to eight leaves will vernalize. Into the Kitchen Collards and kale offer many pickings of fresh greens at a time of year when there's little else to harvest. Folks often say collards are sweeter after the first frost, but an actual 32oF frost isn't crucial.
Cool weather is enough.
The southern way to harvest is to break off the larger leaves, but not the lowest ones, which tend to be tough, dirty and somewhat yellowed. The rest of the plant continues to make more leaves for subsequent harvests. If I want a few leaves to chop into a winter salad, I take the tenderest few from the top. In Thelma Reaves's neighborhood, they begin to cut the whole central head of the cabbage-collard types when serious cold weather is expected, traditionally around Thanksgiving. Central heads are the main collard crop December through February in Ayden, whereas just the leaves are picked spring through late fall, according to Thelma.