The large, thick leaves of sea kale require that this winter and spring vegetable shall have plenty of space in the garden, where it should be given a permanent site in the manner of rhubarb. It is not an economic plant for the allotment, but gives excellent returns over a number of years when a sunny position and rich soil can be spared for it in the home garden.
Parts eaten are the stems and leaf stalks, which require to be blanched as explained below.
Varieties: Lily White, Ivory White, Ordinary.
Roots can be purchased for planting in March, and a stock can easily be worked up from root cuttings. Raising from seed is a slow business, plants not being profitable until they are two years old; a small packet suffices, and germination takes about twenty days.
Ready for Use. The blanched stems are available from February to June outdoors; earlier in heat.
Soil Preparation. Sea kale in its wild form is a coastwise plant and accustomed to salty conditions. Seaweed is to its liking, buried thickly below the top 9 in., the soil below that depth being well broken up. Growers not within reach of free seaweed should enrich the ground with rotted manure or vegetable refuse well decayed. The soil needs to be well-drained, clay or other heavy ground being brought to that condition by the digging in of mortar rubble, sand, grit or ashes.
When and How to Sow.
Seed is scattered very thinly in 1 in. deep drills in March or April. Before the seedlings jostie one another they are thinned out to stand 6 in. apart.
A year from the date of sowing they are fit for planting in their final positions.
How to Plant.
Purchased roots, from 4 in. to 8 in. long, should be planted in March, 2 ft. apart, upright in the ground, the tops covered with about 1 in. of soil. Only one bud should be allowed to remain at each root-top, others being removed with a knife; theobject is to keep each plant single.
Root Cuttings. Side roots can be taken from the main roots (or crowns) of older plants when these are dug up for forcing in a temperature of about 50 degrees; or they can be taken from a plant lifted for the purpose of increasing the stock.
The thin side roots, which will be about in. thick, are cut away and divided into pieces about 5 in. long, for planting in March or April. Each is dropped upright into a hole of sufficient depth and diameter to take it comfortably, the tops to be covered 1 in. deep. Space them out 2 ft. apart, and when top growth appears reduce the shoots to one per plant.
As a guide to which is top and bottom of these root cuttings they should each be cut square across at the upper end when removed from the main root, the lower end being trimmed slantwise.
Cuttings taken from roots lifted for forcing should be buried flat in a heap of soil, to await planting time (March).
Every properly planted root cutting is pretty certain to grow; those not large enough (about 2 in. across the top) to give strong growths for blanching the following winter or spring will be well developed by the next season.
In the summer season the crop responds to generous watering, and the surface around the plants should be kept loose with the hoe. A big handful of agricultural salt per square yard should be hoed in during June and again four weeks later, the dressing to be followed by watering if it does not rain within a day or so.
White flowers are produced in early summer, on 18-in. stems – if allowed to. Seeding will weaken the plants, so the stems should be broken out at the base before they have a chance to lengthen.
The only really troublesome pests which affect young shoots are slugs, attracted by the young shoots on their first appearance. A broad circle of soot or lime around each plant will serve as protection, put down before the blanching operation begins.
To secure the blanched (whitened) stems and leaf stalks, each plant should be covered in winter, when it is leafless, with an inverted box or tub; or, as soon as the first growths are visible above ground, with a 3-in. deep mound of sifted fire ashes; or soil can be hoed up along both sides of a row of plants to cover the crowns to that depth. Before the growths push through the mound the depth of this should be increased to about 7 in. By the time the growths have reached that length they will be fit for cutting.
How to Force Sea Kale.
If plants can be covered, in November or December, with invertedboxes or tubs or large flower pots, and these in turn covered, a month later, with a mixture of fresh stable manure and dry leaves, production of blanched growths will be considerably hastened.
For forcing in a greenhouse with a temperature of 50 degrees or more, strong roots should be lifted any time between November and January and planted – after the removal of side roots – close together in a box about 1 ft. deep, with soil between and around them, the root-tops just covered. The box is then placed under the greenhouse bench, water of the same temperature as the greenhouse is given, and light is excluded by placing an inverted box on top.
Or prepared roots can be planted similarly in pots deep enough to hold them, with inverted pots of the same size placed on top, the drainage hole of each upper pot being covered with a flat stone or piece of wood to block out all light.
If watering is carefully attended to, blanched growths will be large enough for cutting in about four weeks. Plants forced in heat are of no further use, and the roots should be discarded. Those blanched outdoors are not affected, and the plants, watered and fed each summer, will yield good crops for years.
How to Cut Sea Kale.
Blanched growths are fit for cutting when from 7 in. to 9 in. long. They should be cut with a knife, together with a -1-in. thick slice of die root-top. When plants are blanched in the outdoor position with mounds of soil or ashes, this material should be removed carefully from all round before the knife is used, or stems may be snapped.
Preparing for Table.
Wash the sea kale thoroughly and remove any decayed or damaged parts, before cooking. As a food it is nutritious and easily digested.