It has been found in the experiments of the Bureau of Plant Industry that the light seed is undesirable and in every case should be separated from the heavy seed and discarded. In order to make a thorough and complete separation, it is necessary to use some form of a wind-blast ma chine which will blow out the light seed without throwing out the heavy seed at the same time. In Fig. 873 is shown a satisfactory seed separate-, by the use of which the light seed can be from the heavy seed and discarded, and the heavy seed used for sowing the seed-beds. The heavy seed produces the most vigorous and uniform young plants in the seed-beds.
The Havana seed variety of tobacco is usually sown in the seed-bed from the middle of March to the middle of April, and the plants are ready for setting out from these beds May 10 to June 10. After sowing the seed, it is desirable to pack the surface of the bed carefully with a roller or heavy plank, in order to press the soil closely about the seed. A good method is to cover the seed by lightly raking the surface with an ordinary garden rake, a method preferred by many experienced growers.
One of the most important points in the raising of a successful crop of Havana tobacco is the care of the seed-bed. It is necessary to water the seed-bed frequently, usually once or twice every day during the early stages of growth. If the beds are artifi cially heated, warm water should be used for this watering process, as cold water cools the beds and checks the growth of the young plants. The surface of the seed-bed should not be allowed to become dry, as a few hours of dry surface will kill all of the young plants. The water should be supplied in the form of a light spray, in order not to disturb the seed or the young plants in the bed or to pack the soil so that in drying it will cake and injure the plants.
The temperature of the hotbeds should be care fully regulated, and in no case allowed to rise above 100° Fahr. during the day, or fall below 70° Fahr.
during the night. If it is possible to maintain an even temperature, the plants will make the most rapid growth, but it is a question whether they will be as hardy as when subjected to the fluctu ating temperatures corresponding to the natural changes between night and day. The beds can be cooled when necessary by raising the sash if the temperature rises, or the temperature can be raised at night by using lanterns set five or six feet apart in the seed-bed, and by covering the sash with heavy cloth, as ordinary blankets, in order to retain the heat. After the young plants reach the
proper size for setting out, usually five to six weeks after sowing in the seed-bed, the sash can be taken off most of the time during the day and the beds watered only when the plants begin to wilt. If the plants come up too quickly in any part of the seed-bed, they should be thinned out by using an ordinary garden rake, as for the Sumatra variety. It is necessary to keep out all weeds. Before pulling the weeds, the beds should be thoroughly watered. If flea-beetles or other biting insects attack the young plants in the seed -beds, apply the same treatment as with the Sumatra tobacco. If fungous diseases begin to grow in any part of the seed-bed, it should be thoroughly aired by rais ing the sash during the day. If this method does not check the growth of the fungus, the beds should be sprayed with a solution of formalin (one part of formalin to 2,000 parts of water). An application of lime dusted over the beds will assist in preventing the spread of fungous diseases.
The field crop.—The preparation of the field for the plants should be begun in the autumn, if possi ble, by plowing the land two or three inches deep and sowing a leguminous cover-crop. These legu minous cover-crops not only prevent washing and loss of fertility during the heavy rains of the fall and winter, but increase the fertility of the soil through the addition of the nitrogen in the tuber cles of these plants and by reason of their exten sive root development, which tends to break up and put the soil in the best possible tilth for the young plants. In the spring the land should be replowed, care being used to see that the cover-crop is thoroughly plowed under, with an application of well-rotted stable manure at the rate of twelve to fifteen tons to the acre. In addition to the use of stable manure, it has been found that the follow ing or a similar fertilizer should be used in order to secure the best results : One ton of cottonseed meal, 200 pounds of carbonate of potash, 500 pounds of starter and one barrel of lime to the acre. This should be sowed on the land after plowing and thoroughly worked into the soil with a disk-harrow or by some other means before the young plants are transplanted into the field.