Glass is not required in growing late plants. The common practice is to sow in the open, and transplant directly to field or garden. Many failures are due to the use of inferior plants. It is important that every possible effort be made to secure strong, stocky plants, ready for the field when all conditions are favorable for setting. It is an advantage to have the seed bed near the field to be cropped, so that the plants can be shifted without much loss of time or drying of the roots.
In selecting and preparing the seed bed, excessive fertility should be avoided, for very rich soils produce weak, succulent plants likely to succumb under field conditions.
The seed bed should be moderately fertile, fine, clear of stones or rubbish which would interfere with drilling, free from germs of diseases infecting the cabbage, and well supplied with moisture, particularly at the time of sowing. In order to have a full supply of moisture to insure germination, the soil should be plowed early in the spring and harrowed often enough to conserve the moisture. A special precaution may be taken by mulching the prepared soil with coarse litter from the stables.
The time of sowing depends upon locality, exposure, variety and purpose of the crop to be grown. For most localities in the North, sowings may be made any time during May; some growers prefer June 1 or later. The latest maturing varieties, as Houser and Danish Ball Head, should seldom be started later than May 15, and earlier sowing is an advantage where the growing season is short, as in the mountain regions of Pennsylvania. Early sowing is important from the standpoint of yield, while late sowing, resulting in retarded maturity, is favorable to a long period of storage.
Extensive growers use drills in sowing, making rows about 1 foot apart, thus providing ample space for tillage with hand wheel hoes. Too heavy sowings should be avoided, as thinning will then be necessary if the seed is good, in order to secure stocky plants. Eight to ten seeds an inch of drill should make a satisfactory stand. If the soil is fine and moist, 1/2 to 3/4 inch of covering will insure germination. Some successful growers prefer broadcasting rather thinly, to avoid crowding of plants. When this is done the bed should be in the finest condition and the seeds raked in lightly with a garden rake.
Some growers prefer sowing where the plants are to mature. The two main advantages are that the expense of transplanting is avoided and there is no checking of growth, which is incidental to this operation. On the other hand, several disadvantages are to be considered. It is more expensive to combat insects when the plants are scattered than when confined to a small area. The expense of tillage is increased, and the cost of thinning must be taken into account. If the soil is heavy, it will become compact before the roots have made any considerable growth. This may result in reduced yields. In light, friable loams the system may be used with "entire success, especially when the cost of labor is high and where transplanting machines are not available. Sowing is done most economically in this system by machines which drop and cover about half a dozen seeds at the required distances. Half a pound of seed is ample for an acre. The rows should be checked to facilitate thorough tillage. Sowing may be a week later than when transplanting is resorted to. When the plants are three or four weeks old they should be thinned, leaving the strongest at each place.
For early cabbage, fall plowing is generally desirable; heavy sods especially must be plowed down in the fall for best results. The vegetable matter will then be partly decayed by spring and of more immediate value to the crop; the soil will be filled with moisture, which should be conserved by harrowing as soon as the ground is dry enough. This tillage operation should be repeated as often as may be necessary to put the land in proper condition for planting and to retain plenty of moisture to make transplanting successful.
The most important factor in preparing soil for late cabbage is the question of moisture. Many failures are due to the late plowing of sods, followed by dry weather, which sometimes continues long after the proper time for transplanting. The only safe practice is to plow rather early in the spring, working down the land, as explained for the early crop.