The bright and gay colours of the greenhouse calceolarias with their curious. Pouchedalways attract attention in the spring. Plants can be raised easily from seed sown from May to July, the earliest sowings providing plants for flowering in April, May and early June of the following year.
The seed should be sown on the surface of sifted seed compost, and because the seed is so fine, no covering of compost is required. The pots should be covered with a sheet of glass and stood in a cold frame until germination takes place, usually within ten days. The resulting seedlings should then be pricked out into boxes and, before they become too large, be moved again into 3-in. pots of John Innes No. 1 Potting Compost. In October another move into 5-in. pots can be given. Using a similar compost.
During the winter the plants are happy in a minimum temperature of 7°C. (45°F.) – they do not like high temperatures – but the air must be kept fairly dry by careful ventilation. Water should be given sparingly at all times, and during winter it must be kept off the leaves and crowns of the plants as much as possible, ormay occur.
I like to give the plants another move to 6-in. pots in February to obtain really good specimen plants. This is well worth doing if there is sufficient space available in the greenhouse. Plants measuring 2 ft. or more across can thus be obtained.
When I am aiming to grow very large specimens, 1 water the plants once with I oz. Of nitrate of soda dissolved in a gallon of water just when they are beginning to show their flower buds. From then onwards feeding the plants once a week with a liquid or soluble fertiliser until they begin to flower will benefit them considerably.
Greenfly are often a nuisance on calceolarias and as soon as the first signs of this pest are seen fumigate with nicotine shreds or BHC smoke pellets. Alternatively, use a systemic insecticide as a control.