Seakale is a salt-tolerant plant native to coastal regions of northern Europe, and it was in those regions that it was first moved into gardens for cultivation as a vegetable. Young shoots need to be blanched (grown in the dark) — by being covered with an upturned clay flowerpot, for example — to make them palatable. The blanched shoots are very tender, so you might never see them in markets. They should make a nice garden or farmden vegetable, though.
growth, longevity, flavor, hardiness, and nutrition. Seakale beet, as it is known in Britain; known as Swiss chard here. I plant chard just as I do kale, except less of it because it is less nutritious than kale (high oxalate concentration limits its availability of calcium), slightly less cold-hardy, and I happen not to like its flavor as much.