This section is from the book "Commercial Gardening Vol1", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Seeds are sown in the open air either "broadcast" or in " drills ", and under glass in pots, pans, or boxes of varying sizes. In the latter case the gardener mixes his compost beforehand, and drains his seed pans or pots more or less carefully and elaborately according to the class of seeds he intends to sow. Special pains are taken with minute seeds such as those of Begonias, Gloxinias, Rhododendrons, etc, and with the spores of Ferns. The gritty surface soil is rendered very fine by passing through sieves of small mesh, and when pressed down firmly makes a fairly solid rooting medium for the plantlets, and also prevents the seeds from dropping down too far from the light. In the case of Orchids, which are now raised from seeds in thousands, the dust-like seeds are sown on the surface of the mossy or fibrous compost in which the parent plant is growing, the little plants being transferred to thimble-like pots when large enough for the purpose.
In the open air, market gardeners and farmers prepare their soil also in accordance with the nature of the seeds. For small seeds the ground, after being ploughed or dug, is well harrowed or raked, and rolled if necessary to secure sufficient firmness. When large quantities of seed are being sown it is more economical and quicker to use a drilling machine. The seeds are put in a box, and drop through a slot at regular intervals in the drills that are made as the machine is drawn or pulled over the surface. The depth of the drills and the distance apart are regulated beforehand. Generally speaking, however, seeds are sown far too thickly, and in the case of such crops as Carrots, Parsnips, Turnips, Beet, Mangels, Peas, and Beans about 95 per cent of the seedlings have to be destroyed to make room for the others to grow. The waste is not so great with crops that are to be transplanted, as every plant almost may be utilized.
When large areas are to be sown broadcast a sowing fiddle (tig. 61) is sometimes used. This contrivance takes its name from the fiddling action of the operator when distributing the seeds. It consists of a light canvas-covered box frame, which is suspended by a strap from the right shoulder, and is carried under the left arm. At the base of the box is a neck with a controlling slide through which the seed passes, its flow being made continuous by a jigger action from an eccentric from a spindle which carries at its bottom a distributing disk. This disk, which has four radiating ribs, is actuated by means of a thong which forms the string of the bow, and which is passed once round the spindle. When reciprocated, as in fiddling, the bow causes the disk to revolve rapidly in alternate directions, thus giving the seeds a throw of 15 to 30 ft. Where Radishes are grown extensively under glass the sowing fiddle is often used for sowing the seeds. Generally speaking, however, it is more of a farmer's than a gardener's implement.