ONION (Fr. oignon, Lat. unio, liberally unity, oneness, applied to a large pearl and to a species of onion), Allium Cepa (nat. ord. Liliaceae), a hardy bulbous biennial, which has been cultivated in Britain from time immemorial, and is one of the earliest of cultivated species; it is represented on Egyptian monuments, and one variety cultivated in Egypt was accorded divine honours. It is commonly cultivated in India, China and Japan. A. de Candolle, arguing from its ancient cultivation and the antiquity of the Sanskrit and Hebrew names, regards it as a native of western Asia.
The onion should be grown in an open situation, and on a light, rich, well-worked soil, which has not been recently manured. In England the principal crop may be sown at any time from the middle of February to the middle of March, if the weather is fine and the ground sufficiently dry. The seed should be sown in shallow drills, 10 in. apart, the ground being made as level and firm as possible, and the plants should be regularly thinned, hoed and kept free from weeds. At the final thinning they should be set from 3 to 6 in. apart, the latter distance in very rich soil. About the beginning of September the crop is ripe, which is known by the withering of the leaves; the bulbs are then to be pulled, and exposed on the ground till well dried, and they are then to be put away in a store-room, or loft, where they may be perfectly secured from frost and damp.
About the end of August a crop is sown to afford a supply of young onions in the spring months. Those which are not required for the kitchen, if allowed to stand, and if the flower-bud is picked out on its first appearance, and the earth stirred about them, frequently produce bulbs equal in size and quality to the large ones that are imported from the Continent. A crop of very large bulbs may also be secured by sowing about the beginning of September, and transplanting early in spring to very rich soil. Another plan is to sow in May on dry poor soil, when a crop of small bulbs will be produced; these are to be stored in the usual way, and planted in rich soil about February, on ground made firm by treading, in rows about 1 ft. apart, the bulbs being set near the surface, and about 6 in. asunder. The White Spanish and Tripoli are good sorts for this purpose.
To obtain a crop of bulbs for pickling, seed should be sown thickly in March, in rather poor soil, the seeds being very thinly covered, and the surface well rolled; these are not to be thinned, but should be pulled and harvested when ripe. The best sorts for this crop are the Silver-skinned, Early Silver-skinned, Nocera and Queen.
Onions may be forced like mustard and cress if required for winter salads, the seeds being sown thickly in boxes which are to be placed in a warm house or frame. The young onions are of course pulled while quite small.
The Potato Onion, Allium Cepa var. aggregatum, is propagated by the lateral bulbs, which it throws out, under ground, in considerable numbers. This variety is very prolific, and is useful when other sorts do not keep well. It is sometimes planted about midwinter, and then ripens in summer, but for use during the spring and early summer it is best planted in spring. It is also known as the underground onion, from its habit of producing its bulbs beneath the surface.
The Tree Onion or Egyptian Onion, Allium Cepa var. proliferum, produces small bulbs instead of flowers, and a few offsets also underground. These small stem bulbs are excellent for pickling.
The Welsh Onion or Ciboule, Allium fistulosum, is a hardy perennial, native of Siberia. It was unknown to the ancients, and must have come into Europe through Russia in the middle ages or later. It forms no bulbs, but, on account of its extreme hardiness, is sown in July or early in August, to furnish a reliable supply of young onions for use in salads during the early spring. These bulbless onions are sometimes called Scallions, a name which is also applied to old onions which have stem and leaves but no bulbs.
The following are among the best varieties of onions for various purposes:-
For Summer and Autumn.—Queen; Early White Naples: these two sorts also excellent for sowing in autumn for spring salading. Silver-skinned; Tripoli, including Giant Rocca.
For Winter.—Brown Globe, including Magnum Bonum; White Globe; Yellow Danvers; White Spanish, in its several forms; Trebons, the finest variety for autumn sowing, attaining a large size early, ripening well, and keeping good till after Christmas; Ailsa Craig; Ronsham Park Hero; James’s Keeping; Cranston’s Excelsior; Blood Red, strong-flavoured.
For Pickling.—Queen, Early Silver-skinned, White Nocera, Egyptian.