After filling the trays with sifted soil, smooth off even with the top and slightly firm down the soil in the trays by means of a small piece of board. Use the edge of a ruler or strip of thin board ([fig. 6]) to form little grooves or furrows in the soil in which to plant the seeds. These little rows should be about 2 inches apart and one-fourth inch deep. Scatter the seeds of tomatoes, early cabbage, peppers, and eggplant, as shown in [figure 7], very thinly in the rows and cover them by sifting a small quantity of soil over the entire surface. Smooth the top of the soil gently and water very lightly.
The box should then be placed where the temperature will remain at about 70° F. If conditions are kept right, the seedlings will appear in five to eight days after the seed is planted. From this time on the plants will need constant care, especially as regards watering. Owing to the fact that the light from a window comes from one side only, the seedlings will draw toward the glass, and the box should be turned each day, so as to keep the plants from growing crooked. Just as soon as the little plants are large enough to handle they should be transplanted to other boxes and given 2 or 3 inches of space in each direction.
Fig. 7.—Starting early plants; sowing seed in the window box.
Where the required number of plants is too great for growing in window boxes, a hotbed or cold frame may be provided. The usual method of constructing a hotbed is to first dig a shallow pit 8 to 18 inches deep, according to locality, and pack it full of fermenting stable manure. The manure before being placed in the pit should be turned over once or twice in a pile, in order to insure even heating. It may then be packed into the hotbed pit and tramped uniformly. Standard hotbed sash are 3 feet in width and 6 feet in length, and the size of the bed should be made to suit the number of sash employed. A framework of boards 18 to 24 inches high at the back and about 12 inches high in front is placed over the manure-filled pit to support the sash. ([Fig. 8].)
About 3 or 4 inches of fine garden loam is spread evenly over the manure and the bed allowed to stand four or five days to warm up before any seed is sown. At first the temperature of the bed will run rather high, and it is best to delay planting the seeds in it until it begins to decline. This can best be determined by placing a cheap thermometer, with the bulb about 3 inches below the surface of the soil, and watching it until the temperature falls below 85° F. before planting the seeds.
If glazed sash are not available for covering the hotbed, heavy muslin may be used instead; the glass, however, makes the most desirable form of covering. Care must be taken to give the bed sufficient ventilation to prevent overheating; as it is liable to heat up rapidly when the sun shines full upon the glass. Watering should be done during the early part of the day and the bed given enough air so that the plants will dry off before night. The bed should be closed before evening, in order to conserve enough heat to carry it through the night in good condition. If the weather should turn severely cold, a covering of straw, blankets, or canvas may be thrown over the bed to protect it.
Fig. 8.—Preparation of a sash-covered frame for starting early plants.
A cold frame is constructed in exactly the same manner as a hotbed, with the exception that no manure is placed beneath it to supply heat.