The beet seed sold in the United States is produced in California, the Middle States, England and France. A small percentage of market gardeners grow their own seed. As the plant is biennial, in order to produce seed the roots must be preserved over winter (325) and planted in the spring as soon as the ground can be prepared. The seed plants grow to the height of about 4 feet and branch profusely; therefore the roots should be planted about 2x3 feet apart.
The seed of the beet is really not a seed, but a fruit, usually containing several seeds and surrounded by a corky pericarp. These characteristics of the seed should be well understood by planters in order to sow properly. As each so-called seed may produce several plants, care must be exercised to avoid sowing too thickly. The corky covering requires a liberal and constant supply of moisture to insure germination.
The early varieties are sown as soon in the spring as the ground can be prepared. From six to eight weeks are required for the roots to attain a marketable size. Under favorable conditions the early varieties are ready for market in the North by June 1. Succession plantings of oval and turnip-shaped beets may be made until the middle of August. Long and half-long varieties should be sown in May, as about five months are required for them to reach maturity. While the long types are used to a considerable extent, oval and turnip-shaped varieties are more popular as well as more profitable for the late crop, because they do not need to be sown until after the ground has produced one or two cash crops of other vegetables, and they are also preferred on the market.
The distance between rows will depend mainly upon whether the cultivating is to be done with a hand wheel hoe or a horse cultivator. Twelve inches between the rows is the standard distance for wheel hoe cultivation, although many prefer about 15 inches. When horses are to be used, the spacing varies from 24 to 30 inches. A very successful grower allows only 18 inches between rows and cultivates with a small mule.
The distance between plants in the row should be governed by the variety and the size of beets desired for market. In planting small-topped varieties, to be sold when the roots are 1 1/2 to 2 inches in diameter, 2 or 3 inches apart in the row will be sufficient space. The larger-rooted varieties which are permitted to grow to maturity should be spaced 5 or 6 inches apart.
Some growers prefer to sow thickly, especially in the early spring. This may be done for several purposes, viz., (1) to insure a good stand of plants, (2) to make certain of enough plants, even if the first to germinate should be killed by frost, (3) to provide a surplus for transplanting, (4) to provide a surplus for greens.
Thinning is very generally practiced in beet culture. The best plan is to attend to this work before the plants are injured by crowding. Many growers, however, prefer to wait until the plants are 6 to 8 inches high, when the ones removed are used for greens.
Ten seeds to the foot of furrow, or 1 ounce to 75 or 100 feet of drill (5 to 7 pounds an acre), should insure a perfect stand. One inch of covering is sufficient in moist soils. The seeds may be sown with a drill, although their angular form is not conducive to uniform distribution. Drills with effective agitators are best adapted to this seed. It is important that the soil be firmed well by the wheel of the drill or by other means. This is especially necessary when there is lack of soil moisture. Beet seeds do not germinate as promptly as many other garden seeds, and a few radish seeds are sometimes sown with them to mark the rows so cultivation may begin early.
Beets do not transplant as readily as many other vegetables, but it is common to reset the thinned plants and to sow under glass, and then set the plants in the open when conditions are favorable. If advantage is taken of a moist soil and of cool, cloudy weather, the operation will be satisfactory. When the work is properly managed there is a gain of possibly two weeks in time of maturity over sowings made in the open. The seed may be sown four or five weeks before the time of planting in the field.