Kale, Brassica oleracea, is a seriously good versatile crop. It comes in lots of different leaf shapes, colours and textures, from the wonderfully indented, dark and tasty Calvo Nero/Nero di Tosacno (see left) to the lovely purple-veined and vigorous Red Russian and the very green and curly Pentland Brig.
It tolerates a lot of cold, yet grows fast in the summer too. Growers like it particularly because it keeps producing leaves up the stem. You just pick the older leaves lower down, leaving the newer younger leaves to carry on growing. It's not uncommon for a kale plant to be still cropping 8 months after the first picking!
There are fewer more nutritious crops than Brassicas. They contain a range of vitamins (E and B complexes), carotenes, vitamin C and some protein.