Any gardener who can maintain a temperature in his greenhouse in winter of at least 7°C. (45°F.), can grow cinerarias. Their brightly coloured daisyprovide a wonderful splash of colour in late winter and early spring. In small it is probably best to grow the Multiflora Nana strains, which grow about 15 in. tall. My favourites are the large-flowered Grandiflora hybrids which have great appeal and grow about 2 ft. tall. Even taller are the Stellata cinerarias which have a branching habit and bear masses of small flowers.
Seed can be sown in April, May and June to provide a succession of blooms. Plants from an April sowing should flower in December or January.
Seed compost should be used, and for the later sowings the seed pans or pots can be stood in a cold frame and covered with glass or paper. This should be removed as soon as the seedlings appear, and when the seedlings are large enough to handle they must be pricked out into boxes of John Innes No. 1 Potting Compost. The young plants should be kept in a light place but be given shade from strong sunshine.
Before the seedlings become overcrowded in the boxes, move them individually to 3-½ in. pots using John Innes No. 1 Potting Compost. Water the boxes thoroughly before disturbing the plants and, provided the potting compost is moist, give no more water for a few days after potting. The final potting is into 5- or 6-in. pots of John Innes No. 2 Potting Compost. Thelevel in the pot must be about 1 in. below the rim to allow for watering. Potting should be done as soon as the roots begin to fill the small pots. At all stages, adequate must be given as cinerarias will not tolerate soil. In the case of clay pots this can be provided by crocks, and with plastic pots extra sand can be added to the compost.
Cinerarias do not like high temperatures and for the summer they are best kept in a cold frame, preferably standing on or plunged in a bed of ashes to prevent rapid drying out. The plants must be given shade from the sun otherwise they will soon wilt, and watering must be attended to carefully. Greenfly and leaf miner can be a nuisance and at the first signs of these pests, spray with a suitable insecticide.
The tops of some of the plants can be pinched out – when they are in their final pots – if it is desired to delay flowering and so provide a longer display of flowers.
Feed with a liquid or soluble fertiliser throughout late summer and autumn until the flowers appear. Then in late September take the plants into the greenhouse allowing them plenty of space. Ventilate freely in suitable weather and water very carefully when temperatures are low.
Although cinerarias are perennials, they are best treated as annuals, raising new plants from seed each year.