This past fall and winter I had an experiment going with 4 Season Gardening and much to my surprise I have successfully grown winter greens, a variety of  lettuce (corn salad-dutch, claytonia- miners lettuce), carrots, beets and onions, oh, and my beloved Kale. Our lowest temperature so far has been 14 degrees and the Kale has grown and supplied us with organic greens all winter. I consider Kale to be "King" of the garden and it also is a super nutritious food. It contains high levels of beta carotene, vitamin A and E. It also provides folate, iron and potassium.  Kale has protein and calcium, in fact just 1 cup of cooked Kale has 6.4g of protein and 270mg of calcium. Also Kale has bioflavonoids the help protect against cancer and like all greens it is high in fiber. Now when people ask me "where do you get your protein since you do not eat meat," I can say I get it from the "King" of the garden! Eat yours greens!