Kale is a robust, easy-going vegetable in cold weather. It doesn't like heat, but it can survive brief temperature dips as low as –10˚F. Frost actually makes kale taste better; it shouldn't be picked until after a hard frost and a few freezing-cold nights.
(Shown: 'Lacinato' kale, or dinosaur kale, a popular blue-gray variety with a heavy texture.)
In warm areas of the South, kale seeds can be sown in October. In cooler climates, seeds should be sown in July for a fall and winter harvest. If transplants are used, plant them up to their first set of leaves; this will promote better rooting and a sturdier plant. Kale will tolerate part shade, but full sun is best. It needs good drainage and prefers slightly alkaline soil. Kale is shallow rooted, so it should be mulched well to keep the soil cool and preserve moisture in the top few inches of soil, where feeder roots can access it. Mulching with compost will make nutrients readily available. Seaweed mulch is also very beneficial to kale.
When harvesting kale, cut several leaves at a time but avoid cutting into the bud at the center of the plant. This will keep the plant producing. To prepare kale for eating, soak it in cold water to clean it, then remove each leaf's tough central rib. Kale can be used as a substitute for spinach or Swiss chard. It works well as a simple side dish if steamed or briefly boiled in chicken or vegetable broth. It is a good addition to stir-fry dishes and to soups. Tear the leaves and add them at the last few minutes of cooking, until they are just wilted.