This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
It is only through careful study of the practical value and correlation of varietal differences, the exercise of great care in selection and growing of the plants, and in the saving of the seed, that this or any vegetable can be improved or even its present good qualities maintained. Under favorable conditions the plant is capable of producing abundant seed, a single plant having been known to yield thirty-five ounces, enough to plant 25 to 40 acres, but such yields are very exceptional, and one-half to four ounces a plant is much more common. Although botanically the plant is self-fertile, when isolated it seldom yields much and often no viable seed. It transmits very persistently through many generations any distinct variation, but often without expression, although such hitherto unexpressed variations are apt to appear in the seed of self-fertilized plants, so that such seed is frequently less uniform than that from a field of plants of the same ancestry. At least one of our popular varieties is made up of the descendents of a single isolated plant, but it is a curious fact that in the second and subsequent generations 90 per cent of the plants, although quite uniform, were very different in character from that of the selected individual from which they were descended.
The originator of one of our best varieties maintains that it is essential to the production of the best seed of that sort that seed-plants of very different types should be set together, and by crossing they will produce seed giving plants of the desired type. In spite of these facts, it is thought that the practice which will give the best results with other plants is equally desirable for the cabbage, and that first a distinct and well-defined conception of the varietal form desired must be formed and the stock started from the plant or plants whose seed most uniformly developed into plants of the desired character, rather than from those in which it was exceptionally well developed. Often even professional seed-growers have but a very vague and constantly changing conception of what a given variety should be. The greatest profit is not from the field that produces even a good many of the most perfect specimens, but from that in which the largest proportion of the plants are most uniformly of the desired character.
In order to produce seed which will give such results, one must first form a very clear conception of just what one wants in plant and head, and learn the relation between easily noted but economically unimportant qualities, and others not so easily seen but more important in determining value. Having selected a number of ideal plants, one should grow these either singly, or in groups of three or four that are nearest alike. Save and number the seed of each plant separately and plant a small sample of each number, carefully noting the numbers in which the product was most uniformly of the desired character. From the reserved seed of the numbers which most uniformly developed the desired form, one can start a stock for field planting. It is not safe, however, to rest there; one must start a new selection of the desired character so as to continually renew one's stock. In raising seed, plantings should be made a little later than one would for fall market cabbage. As the plants develop, each lot should be repeatedly looked over and not only those which show no disposition to form a head, or one in which the inclosing leaves do not pass over the center, but also those which show any departure (even if it be of itself a desirable one) from the desired form, should be removed.
The plants should be left in place until there is danger of the ground being closed by frost and should then be pulled, a few of the larger leaves removed and then packed into narrow trenches in sheltered and well-drained localities, taking pains to pack the earth closely about the roots and stems. Gradually, as necessary to prevent hard freezing, they should be covered with earth and with coarse litter, the aim being to keep them as cold as possible without actually freezing, and to prevent them starting into growth. As early in the spring as possible, they should be set for seeding, giving each plant about twice the space needed for market cabbage. In setting, the plants, should be more or less inclined, so that while the top of the head is but little above the surface, the roots are not buried in hard and cold subsoil. As they are set, the heads should be scarred across the top, not deep enough to injure the sprouting center, but so as to facilitate its pushing its way through the head. The seedstalks should not be cut until they begin to shed the seed, which turns black and seems ripe before it is fully mature.
The entire plant should be cut and stored until quite dry, when the seed can be easily threshed, cleaned, and spread not over 1/2 inch deep in full sunlight for a few days and then stored.
Figs. 710, 711.
Fig. 710. Wild cabbage plant in seed. Chalk cliffs of England.
Although one occasionally sees heavily seeded plants in all parts of the United States, cabbage seed rarely proves a profitable crop, except in very limited areas along Long Island Sound, the eastern shores of New Jersey, Maryland and Virginia, and in the Puget Sound region, where the yield commonly secured varies from 300 to 700 pounds to the acre, although exceptional crops sometimes reach 1,500 to 2,000 pounds. The common method of growing does not vary materially from that described, except that very often too little care is exercised in securing stock seed, and it is sowed or the plants set so late that they fail to develop sufficiently to enable one to do very effective rogueing out of inferior stock. In Holland, seed is often raised from much better matured heads than are commonly used in America and which are cut from the root, but leaving more stem than for market use, and planted so that the top is level with or slightly below the surface. Treated in this way, they root like a great cutting and form loose, well-branched plants which are not so liable to injury from wind, and are said to yield more seed than would be produced if the entire plant was used.
It is possible that this method might give good results in the Puget Sound region, but it would not in the East. W.W Tracy.
Fig. 711. Cultivated cabbage in seed.