Strasburg (Philadelphia Yellow Dutch) produces a somewhat flattened bulb. The variety is widely grown for sets.
Silver Skin (White Portugal) is a well-known white variety grown extensively for sets.
Southport White Globe produces a large globular bulb from seed sown in field or garden.
Silver King is an excellent variety for sowing in the open. The bulbs are large and possess good keeping qualities.
White Pearl is a very early variety. Bulbs are medium sized, mild, pure white and very attractive. They do not keep well, but are valuable for the early market.
White Queen, an extremely early onion, produces small, pure white, very mild bulbs, largely used for pickling.
Early Red is valued as a red, early-maturing variety.
White Barletta is an extra early white onion, which keeps well and is excellent for pickling.
White and Yellow Multipliers (potato onions) are planted extensively for bunching. (544.)
The Egyptian (Perennial Tree Onion) is a perfectly hardy variety of medium quality, valued for fall planting in the North to produce early spring bunching onions. (544.)
The bulbs of Bermuda, Spanish and Italian onions are much larger than those of the American class. They also require a longer season to mature and are not so hardy. The flesh is more tender, and milder, but the bulbs do not keep as well as those of American onions. They are nearly always started under glass in this country, even in southern districts.
Prizetaker seed was first grown in California from a shipment of Spanish bulbs. The variety has become very popular in the United States, especially for the transplanting system of culture. The bulbs are very large, often weighing more than a pound; bright yellow, thin skin; flesh white, fine-grained, mild, with a delicate flavor. They possess only fair keeping qualities.
White Italian Tripoli produces very large, white, flattened bulbs.
Gigantic Gibraltar and Denia produce bulbs similar to those of the Prizetaker, but require more time to mature. They are also milder in flavor.
Fortunately, it is possible to select varieties suitable to a wide range of climatic conditions. The most tender sorts of the foreign types, as the Bermuda onions, thrive in some parts of Texas, Florida and Southern California, and do well at the North when started under glass. They often, too, produce excellent crops when sown in the open, under the most favorable conditions. All the American varieties thrive in the northern states, and with proper culture generally do well in the South. The multipliers or potato onions are thoroughly at home throughout the South, and with some winter protection may be grown for early bunching in the North. The Egyptian or Perennial Tree onion is hardy in the North, even without protection.
While this vegetable may be grown successfully under a wide range of climatic conditions, it succeeds best in temperate regions without great extremes of heat and cold. When grown in the far South, as in Texas, advantage is taken of fall and winter. The crop is planted in September and harvested in March and April. From 130 to 150 days are required to mature bulbs of the various varieties. A bountiful supply of soil moisture is necessary early in the season, when the plants make very rapid growth. A dry soil and low humidity are important for ripening, harvesting and curing the bulbs.
Land to be used in growing onions should be practically level to prevent damage from washing. The seeds, sets, or young, shallow-rooted plants are easily washed out on sloping lands. The soil should be retentive of moisture and yet well drained, friable, easily worked, fertile and free from stones and rubbish which would interfere with the proper use of drills, hand and wheel hoes.
Vast areas of muck and peat soils are devoted to the culture of onions. The crop is doubtless grown at less expense in these soils, which abound in vegetable matter, than in other types requiring more manure and fertilizer and a greater expenditure of labor. Their dark color causes them to warm up rapidly in the spring, and thus they favor early planting, which is universally regarded as important. These soils, rich in organic remains, retain moisture, so that drouth seldom curtails the crop to any great extent.
Sandy loams, when properly enriched with humus and plant food, furnish excellent conditions for onions. They are easily worked and produce solid, heavy bulbs of superior keeping quality.
Clay soils should be avoided. They become too hard and compact for best results. Clay and alluvial loams, when properly "handled, yield profitable crops, but the supply of humus must be liberal to prevent serious baking. Incrustation is especially damaging when it occurs before the plants are up or large enough to permit thorough tillage.
Inferior seed is the source of heavy and frequent losses in onion culture. Onion seed must be fresh, never more than a year old and produced from bulbs of a superior character. Some seed firms have established reputations for selling high-grade seed of this vegetable, and growers should exercise extreme care in ascertaining the best sources of supply.
While it is less difficult at present to procure good seed than formerly, a large number of gardeners and onion specialists raise their own seed. The bulbs are best selected at harvest. They should be of the desired size and form. A short neck is considered an advantage. Uniformity in all of the essential characteristics is exceedingly important in choosing bulbs for seed purposes. Seed bulbs should be stored as directed in this chapter (541) and planted as early as possible in the spring. (Some growers prefer fall planting.) The ground should be only moderately fertile, especially in nitrogen. Furrows are made 4 or 5 inches deep and 14 to 30 inches apart, depending upon the method of cultivation. After placing the bulbs about 6 inches apart in the bottom of the furrow, they are covered with a hoe or a small plow. The long, slender seed stalks should have some support, which may be provided in two ways: (1) By ridging with soil to the height of 7 or 8 inches, the usual plan, and (2) by driving stakes at the ends of the rows and at frequent intervals and then stretching cheap twine on either side. When mature or ripe the heads turn yellow. At this stage they should be removed promptly with 6 to 8 inches of the stalk before any seed is lost. As the tops do not ripen at the same time, it is necessary to make several cuttings to prevent loss. A tight vessel, or basket with a cloth lining, should be used in collecting the seed. The tops are spread in an airy room with a tight floor until dry enough to separate with a flail or by other means. Winnowing will remove most of the chaff. The seeds may then be placed, a few pounds at a time, in a vessel of water. The heavy seeds, which sink, are saved, while the light ones and the remaining chaff are poured off. After thorough drying and curing, the seeds may be stored in any dry room.