Prepare the surface earth well, to make a good seed-bed. Plant when the ground is moist, if possible, and preferably just before a rain if the soil is of such character that it will not bake. For shallow-planted seeds, firm the earth above them by walking over the row or by patting it down with a hoe. Special care should be exercised not to sow very small and slow-germinating seeds, as celery, carrot, onion, in poorly prepared soil or in ground that bakes. With such seeds it is well to sow seeds of radish or turnip, for these germinate quickly and break the crust, and also mark the row so that tillage may be begun before the regular-crop seeds are up.
Land may be prevented from baking over the seeds by scattering a very thin layer of fine litter, as chaff, or of sifted moss or mold, over the row. A board is sometimes laid on the row to retain the moisture, but it must be lifted gradually just as soon as the plants begin to break the ground, or the plants will be greatly injured. Whenever practicable, seed-beds of celery and other slow-germinating seeds should be shaded. If the beds are watered, be careful that the soil is not packed by the force of the water or baked by the sun. In thickly sown seed-beds, thin or transplant the plants as soon as they have made their first true leaves.
For most home-grounds, seeds may be sown by hand, but for large areas of one crop, one of the many kinds of seed-sowers may be used. The particular methods of sowing seeds are usually specified in the seed catalogues, if other than ordinary treatment is required. The sled-markers (already described, p. 108) open a furrow of sufficient depth for the planting of most seeds. If marker furrows are not available, a furrow may be opened with a hoe for such deep-planted seeds as peas and sweet peas, or by a trowel or end of a rakestale for smaller seeds. In narrow beds or boxes, a stick or ruler (Fig. 115) may be used for opening creases to receive the seeds.
The depth at which seeds are to be planted varies with the kind, the soil and its preparation, the season, and whether they are planted in the open or in the house. In boxes and under glass, it is a good rule that the seed be sown at a depth equal to twice its own diameter, but deeper sowing is usually necessary out of doors, particularly in hot and dry weather. Strong and hardy seeds, as peas, sweet peas, large fruit-tree seeds, may be planted three to six inches deep. Tender seeds, that are injured by cold and wet, may be planted after the ground is settled and warm at a greater depth than before that season. As a rule, nothing is gained by sowing tender seeds before the weather is thoroughly settled and the ground warm.