This section is from the book "Commercial Gardening Vol2", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Not so very many years ago the only Cinerarias in general cultivation were the members of the florist's section, that is to say, those of short sturdy growth and massive heads of large flowers. Now there are many other types, particularly the "stellata" or "cruenta" class, with smaller flowers, and a looser habit of growth. This group is very popular in many private establishments, but from a commercial standpoint the others are preferable, as they meet with a more ready sale. In the case of plants that often pass from hand to hand before they are finally disposed of, freedom from injury under such conditions is an important consideration, and the shorter and stouter habit of the florist's varieties enables them to better resist continual changes than the taller and weaker-habited stellata varieties. Still, a certain number of these last may sometimes be grown to advantage.
Cinerarias may be readily raised from seed. This is usually sown in May and June, though for blooming before Christmas it may be sown in April. The seed is sown thinly in pots, pans, or boxes, using a compost of equal parts of loam and leaf mould, with a good sprinkling of silver sand. The seeds, being very minute, should be carefully attended to in the matter of watering, shading, etc. When the young plants are large enough to handle they are pricked off into pans or boxes, and when the second leaf appears the plants are potted singly into 2½ -in. (thumb) pots. A cold frame is then the best place for them, as they dislike draughts but need plenty of air. They must be shaded from the sun. Frequent sprinkling overhead is of great service during bright weather, and overcrowding is particularly harmful. For the final potting, equal parts of loam and leaf mould, with a sprinkling of bone meal and silver sand, form a very suitable compost. A light airy structure is the best place for the plants during the winter. As the pots get full of roots, give an occasional stimulant.
Aphides or Greenfly are sometimes very troublesome, and so are Thrips if the atmosphere is too dry. These can be kept under by vaporizing with nicotine. For mildew, dust with sulphur, and allow as free a circulation of air as possible. Slugs also must be looked after. A leaf-mining maggot is sometimes very troublesome, but may be checked by early fumigation. [w. t].