This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Next to Chinese Primroses, Cinerarias are perhaps the most useful winter and spring flowering greenhouse plants in general cultivation. By sowing the seeds at different times, they may be had in bloom all the year round, but from November to May is the time they display their greatest charms, and are of most value to the cultivator. They deserve better treatment than is generally bestowed upon them, and few plants better repay a little extra attention to their peculiar requirements.
Clean well-grown plants remain a considerable time in bloom; and where cut flowers are in request, they are very useful for cutting from. Nice little plants in 6-inch pots look very well in combination with Ferns, and are handy for filling large vases in entrance-halls, rooms, etc. The preservation of the foliage in a clean healthy condition is the only difficulty in their culture. If from any cause the foliage is destroyed, the plants are useless for decorative purposes. To preserve it in a healthy state, the plants must never be allowed to suffer for want of water; they must be kept clear of insect life, and never exposed to currents of dry hot air rising from hot-water pipes or flues.
Of insect life, thrip and greenfly are the most troublesome. Fumigation with tobacco is the best remedy for their destruction, and as soon as they are observed should at once be applied, taking care that the foliage is quite dry, and the atmosphere of the house, or whatever structure the plants are in, is in as dry a state as possible. If this is not attended to, the foliage is apt to suffer from the effects of the tobacco smoke.
The maggots alluded to by W. H. in the April number of the 'Gardener' are some years very troublesome, and, unless their ravages are stopped, soon destroy the beauty of the foliage. They are partial to the leaves of healthy, well-grown plants, and infest them in all stages of their growth. There is no remedy, so far as I know, for their destruction, but picking them out of the leaves with a common pin or point of a pen-knife. They are easily seen by turning up the leaves and examining the under sides of them, and if picked out soon after their first appearance, they do very little harm.
The common practice at present is to raise Cinerarias from seed, and some gardeners recommend the first sowing to be made in March; but if the plants are not wanted to flower until the New Year, the first week in May is time enough to sow the seeds. A second sowing in July will supply plants to bloom in March and April. In preparing the seed-pan, be careful to have it properly drained. Use loam and leaf-mould in equal parts, adding as much sand as will keep it from getting sour. Fill the pan to within ¾ of an inch of the top, pressing the soil rather firm, and make the surface quite smooth, on which sow the seeds as evenly as possible. Cover them not more than 1/8 of an inch deep with finely-sifted soil, over which spread a piece of muslin or blotting-paper, and give a good watering through a fine rose. When the water subsides, remove the muslin or paper, and place a square of glass over the pan. Set it in the propagating pit or frame, and keep it shaded until the seedlings are fairly up. As soon as they can be handled, prick them out 3 inches apart in boxes, using soil the same as for the seeds. Place the boxes in a cold frame, facing the north; keep close and shaded for a few days, after which time remove the shade and admit an abundance of air.
As soon as the leaves of the individual plants begin to touch each other, transfer them into 4-inch pots, using a compost of two parts loam, one part leaf-mould, and one part old cow-dung, adding as much sand as will keep it open.
After placing 3 or 4 inches of cinders at the bottom of the frame to stand the pots on, return the plants to their old quarters. As soon as they fill the pots with roots, shift into the sized pot you intend them to bloom in, using soil the same as before. Keep the plants as long in the cold frame or pit as you are certain you can keep frost out. Attend to watering and keeping insects at bay, and you will be rewarded with fine heads of bloom for your trouble. J. H.