There are three essentials for the successful germination of seeds of all types - moisture, warmth and air. In addition, most seeds germinate best in darkness; there are a very few which respond best when exposed to light. The depth of sowing is governed by the size of the seed; as a general rule, seeds should be covered by a layer of soil that is equal to about twice their own depth. Some seeds, however, should be sown deeper because they have a tendency to push up to the surface as they germinate. Some beans, for example, should be sown 1 to 4 in. deep, and peas should be sown 2 to 3 in. deep. Most small seeds need only a very light covering of fine soil.

Outdoor sowing should be in properly prepared soil or seed-beds. It is useless to sow seeds in loose, freshly dug soil. Always firm the surface by treading or rolling, then rake it evenly to remove stones and create a fine tilth or surface covering of crumbs. On heavy, clay-like soils add sand, fine coal cinders or other gritty material-as well as peat moss, commercial humus, well-decayed compost or other suitable organic matter - to the surface to make it easily crumbled.

The actual times for sowing vary according to region, season and soil conditions, and no hard-and-fast rules can be laid down. Do not sow until the weather is right and is expected to remain reasonably favourable to the growth of the kinds of seeds
that are to be sown.

Once the seed-bed has been prepared, the seeddrills - little shallow trenches in which seeds are sown - should be drawn. Using a carpenter's rule graduated in feet and inches, measure off the prescribed distances between the rows on opposite sides of the plot, and place small stakes to mark the ends of the rows. Then stretch a good strong garden line (a plastic clothes-line is ideal) across the plot from stake to stake, and draw out the seed-drill along one side of the line to the correct depth.

For making shallow drills, use a stout stake or the handle of a broom, rake or hoe. The end of a pencil will make an ideal drill for smaller seeds such as cabbage and lettuce. For larger seeds a small draw, hoe or a triangular hoe can be used. Flat-bottomed drills should be drawn, particularly for the larger seeds, because they allow an even distribution. If the drills are V-shaped the seeds will run together at the base of the drill.

Water the soil well before sowing, using a very fine rose on the watering can or a fine mist spray. Watering along each drill before sowing is of advantage. If the soil is well moistened before planting, there is not the same need for frequent watering while the seeds are germinating.

The ultimate success of a crop depends on the thin sowing of the seeds. Thick sowing results in enfeebled seedlings because of overcrowding and lack of light; and much time and patience will be required to thin out the overcrowded young plants in order to leave the proper growing space for those that remain. There are usually far more seeds in a packet than are required, and it is a great mistake to sow them thickly in order to use all of them.

Successive sowings are an advantage with short-duration crops.

After sowing, cover the seeds by using the back of a rake, then gently firm the soil over the seeds along the lines of the drills. Label each kind distinctly and give the date of sowing and any other particulars that may be helpful.