Growing sea-kale | Site and soil | Varieties | Sowing | Planting | Forcing | General Care | Troubles
In a variety of ways, sea-kale is an unusual vegetable. It is one of the few vegetables that is a native plant, native to Ireland and northern coasts of Europe but it is a rare plant at this stage. It favours shingle and gravelly beaches and is normally found not far from the high tide mark where is benefits from masses of seaside and other sea-borne organic matter. A member of the cabbage family, Crambe maritima has thick blue green leaves, that are very robust and wind and salt-resistant, coated with protective wax. Its seeds are borne in a corky pod that can be carried on the tides and deposited with debris at new sites.
It is only grown as a vegetable in a limited way and it is also unusual in that it is one of a few vegetables, such as chicory, endive and rhubarb, that are blanched for use. These leaves would be far too coarse and bitter to use, but when blanched make an excellent and very tasty vegetable, cooked like fresh asparagus. It is an easily grown perennial vegetable and can be grown as a very attractive addition to a flower border, its superb large blue leaves being a good contrast for orange and white flowers. Its flowers, cabbage-like, are not unattractive though it is not worth growing the plant for these alone. The plant could be forced in situ in a flower border just as easily as in a kitchen garden.
Site and soil
Being a seaside native plant, sea-kale loves an open sunny position. The soil should be open and free-draining and sandy if possible, though rich with plenty of well-rotted organic material.
It is quite difficult to acquire seeds of sea-kale because it is such an uncommon vegetable, but vegetable specialist seed houses such as Marshall's stock it. The current Marshall's catalogue lists two varieties, one of which ‘Angers' is only available as thongs and is not sent to the Republic of Ireland but seeds of the standard variety ‘Lilywhite' is.
Sea-kale is very easy to raise from seeds, usually the packet contains only five or six seeds but that is as many plants as is generally needed. Sow the seeds singly in pots with some sand to keep it well drained. The seed germinates quickly and the young seedlings can be grown on in the pot. Plants sometimes self-sow in the garden.
Being a perennial vegetable, it will occupy the ground for several years, perhaps decades. Spacing is about 50 to 60 centimetres apart but old plants can be much wider.
The leaves die back in winter and rot away. The roots can be lifted for early forcing in winter in a heated place, or left until spring and forced in situ by covering with a large pot or other container that completely excludes light.
After the forced leaves and stems are cut, remove the cover and allow the plants to produce new shoots and grow away for the remainder of the summer. Mulching with some wll-rotted manure of compost will keep the plants growing well.
Generally trouble free, white butterfly caterpillars sometimes have a go and watch for slugs at the shoots when being forced.