The time to start the tubers into growth is late winter or early spring, but the point to bear in mind is that a temperature of 6 5 ° F (18°C) is initially required, and when the shoots appear a minimum temperature of 55°F (13°C) is needed for growth to continue. Tubers started in late winter will usually bloom in late summer and early autumn. Tubers started in spring will bloom in autumn. If you do not have the facilities to maintain a minimum temperature of 5 5 ° F (I3°C) during early spring it is better to delay potting until mid-spring so that the shoots do not appear until the weather is warmer.
Make sure the compost is moist but not wet and do not water until absolutely necessary, as too much moisture at this stage before any appreciable root growth has occurred can result in tuber rotting. Place the pots in a temperature of 6 5 ° F ( 1 8 ° C ) until shoots appear, after which the plants can be moved to a slightly cooler place. A temperature of 6 0 °F (15°C) is ideal.
The tuber should be placed on its side in the compost about in (13 mm) below the surface, using JI potting compost No.2 or compost E6. Pot four tubers in a 5 or 6-in (12.5 or 15-cm) half-pot, which is quite adequate for the root run, and gives a better balance of pot to flower.
Apart from watering as required, the plants do not require any further attention until they have flowered. When grown in a greenhouse they should be given light shading in the late spring and summer months. When the plants have finished flowering, they should be allowed to dry off gradually until the leaves begin to wither away, at which stage withhold water altogether, and allow the compost in the pots to become completely dry. The pots can be stored under the bench in the greenhouse (providing you can maintain a minimum temperature of 4 5 ° F / 7 °C on average), laying each pot on its side.
The tubers will not come to any harm with an occasional short spell at 4 0 ° F (4°C) if the pots are bone dry, but should not be kept in temperatures below 4 5 ° F (7°C) for weeks on end. At the end of the winter knock the soil out of the pots and carefully sort out the tubers, which should then be started into growth as already described.
