Sea Kale
(Crambe maritima). A hardy, herbaceous perennial, a native of Britain. It is very extensively cultivated in gardens as a vegetable for forcing, and for use in spring when the season's growth commences. The young shoots and leaf-stalks are the parts cooked when they are crisp and well blanched. The stronger these can be obtained, the better; the chief object is, therefore, to cultivate with a view to securing good, large roots and crowns previous to forcing them. Sea Kale may easily be raised from seed, which should be sown in an open situation at the end of March, or early in April, according to the state of the soil. Sow in drills 12in. apart, and thin the young plants to about 6in. asunder in the rows for the first year. Before the next spring, the roots must be lifted, and replanted in rows from 2ft to 2 1/2ft. apart, for growing into a size large enough for use. All the crowns and buds at the top must be cut off before replanting, and the roots inserted so that their tops are 1in., or even 2in., below the surface. Sometimes, Sea Kale is sown at wider distances than those above given, and the plants allowed to grow for two years without being transplanted, when the tops may be blanched and used; but when thus treated the tops of the crowns must be cut off, to prevent the plants seeding the second year. The greater part of the Sea Kale plants grown specially for forcing are raised from cuttings made from the roots. When a quantity of fully-developed crowns are lifted for forcing, there are plenty of pieces to be detached from the main root; these are sometimes called thongs, and any about 4in. in length will do for planting. They should be cleanly cut through with a knife, the upper end straight, and the lower or smaller end on an angle, in order that each may be readily distinguished at planting time, which will be in the following March, or early in April. Meanwhile, during winter, these prepared root-cuttings must be buried in a heap of sandy soil. All the larger roots that have been forced may also be cut over and replanted, but it is advisable to keep growing some young ones each year. The roots covered with soil will have been forming shoots by early spring all round the crowns; they should be planted about 1ft apart, in trenches, which require to be 2ft. asunder, to allow the leaves to develop. The crown portion of the cutting must be placed so as to be covered with soil. The numerous shoots which appear may, in due course, be reduced to one, the strongest; this will then grow rapidly, if the soil is rich and of good depth. After the leaves die away in autumn, the roots, if intended for forcing under glass, may be lifted, covered temporarily with soil, and protected until required for introducing into heat. During this process, any pieces of roots large enough for cuttings may be collected and treated for another year in the way above described. Root cuttings taken from plants that have not been forced are much stronger and superior to those saved from forced and, consequently, weakened stocks.
Forcing. Sea Kale is one of the easiest of plants to force, provided heat is very gradually applied: it will not withstand a high temperature at first. An easy method, where a supply of crowns has been prepared, is to place several nearly close together in large pots, and stand them in a temperature of about 45deg., turning an empty pot over the top, to exclude light. The floor of a mushroom-house is generally a good place, and, as this structure is usually kept dark, the shoots become blanched as they grow without being covered. They should be cut for use when at the stage represented, and detached at the crown as shown. Sea Kale may also be forced in the ground by inverting over it large pots specially made for the purpose, and covering with fermenting material. A gradual heat is necessary, a very little at first is sufficient to excite growth. Light must always be excluded during the forcing process, in order to insure thorough blanching.