Cyclamen: Growing Conditions
Cyclamen give a wonderful display of colour from autumn until spring, and they are one of my favourite pot plants. To grow well, the plants need a minimum temperature in winter of 10°C. (50°F.). Plants are raised from seed and there are strains available with pink, red, white, violet and crimson. There are also types that have frilled edges to their petals and these make charming companions for the usual kinds.
I sow cyclamen seed in June but sowing can also be done in August to provide plants for flowering at the end of the following year. Some gardeners also sow in January but at that time of year it is often difficult to provide sufficiently high temperatures to germinate the seed.
The seed should be spaced out evenly on the surface of a pan of seed compost, and covered lightly with sifted compost which is then firmed. The pan should be covered with a pane of glass and a sheet of newspaper to prevent rapid drying out of the compost. Wipe the condensation from the glass daily and remove the coverings as soon as the seed germinates. The pan is then stood in a warm, shaded part of the greenhouse.
When the seedlings are large enough to handle, lift them carefully with a dibber and prick them out into boxes of John Innes No. 1 Potting Compost. This must be done before the seedlings have too many roots. Some seeds take several weeks longer than others to germinate so the seed pan should not be discarded until the required number of seedlings has appeared. Hold the seedlings by their seed leaves to avoid bruising the delicate stems. Space the seedlings about 1-1/2 in. apart.
The First Potting
New growth is soon made in warm, moist conditions with shade from the sun. Before the seedlings become overcrowded pot them singly in 3-in. pots, using John Innes No. 2 Potting Compost to which extra coarse sand has been added to give the plants really good. Firm the around the roots with the fingers and be careful not to set the plants too deeply. Leave a space between compost and pot rim for watering. A winter temperature of 10 to 13°C. (50 to 55°F.) is adequate and the pots can be stood on a greenhouse shelf so that they get the maximum amount of light available.
The Final Potting
As the plants fill their pots with roots they should be transferred to their flowering pots, the strongest going into 6-in. pots and the weaker ones into 5-in. Use John Innes No. 2 Potting Compost, making it moderately firm, and keep the top of thejust above soil level to prevent it from rotting off.
Cyclamen like cool conditions in summer and the best place for them is a cold frame with shade being provided from the sun. Sinking the pots in a bed of ashes reduces the frequency of watering. Overhead sprays of water are beneficial and the frame lights can be removed entirely at night. Allow plenty of space between the plants, and as the roots fill the pots, feed the plants each week with a suitable fertiliser.
Towards the end of September and before hard frosts arrive the plants must be returned to a frost-free greenhouse. At this time remove any dead leaves and green slime from the pots. Free ventilation is needed, and on warm days damp the floor and staging with water to maintain a humid atmosphere.
If aphids are seen spray the plants thoroughly with a suitable insecticide. Small cream-coloured grubs are often found feeding on the roots of cyclamen. These are the grubs of the vine weevil (which also attack begonias). The use of BHC insecticide will destroy them and where this pest is troublesome. Dust the potting compost with BHC.
As the weather becomes cooler and there is less heat from the sun pay particular attention to ventilation to avoid conditions becoming damp and stuffy. Sufficient heat should be provided to keep a steady temperature of at least 10°C. (50°F.) at night. Should signs of the grey mould fungus (botrytis) appear, which is common when conditions are too damp, a fungicidal dust can be applied with a small puffer. Any leaves that shrivel must be removed as botrytis often starts to develop on a damaged leaf.
The first flowers appear in early autumn but I remove these until the main ‘flush’ of flowers develop. The way to remove a flower is to hold the stem between the thumb and first finger and give a sharp tug. The stem should then come away cleanly without leaving a piece at the base which could rot and cause trouble later on.
Watering and Feeding
This must be done very carefully in winter. The compost must not be kept too wet otherwise the flower and leaf stalks will rot. When applying liquid fertilisers take care to sec that none of the liquid touches the leaves or scorching will occur.
As the flowers fade they should be removed – by giving the stems a sharp tug – so that the plant does not waste energy on producing seed.
The best plants can be kept for another year and once flowering has finished they should be put to one side in the greenhouse where they can continue to grow for a while.
During the summer the corms should be allowed to rest by withholding water, although I do not think it is wise to dry them off completely as it is very often difficult to start dry corms into growth again.
In July watering can begin again and if plants are sprayed overhead with water it will help to encourage new growth.
As young leaves appear the plants should be repotted. All the old leaves should be cleared away and the plants tapped out of their pots. Some of the old soil can be scraped away so that the plant can be put in a clean pot of the same size: 5- or 6-in. Fresh John Innes No. 2 Potting Compost should be used. Keep the corm slightly above the level of the compost.
The plants soon make progress if stood in a shaded cold frame and given similar treatment to younger plants. Water sparingly after repotting but give more water once roots have formed. The plants should flower at about the same time as those raised from seed. Plants more than two years old lose vigour and are not worth keeping, in my opinion.