An ever-increasing number of greenhouse owners are taking an interest in succulent plants, especially cacti. These plants are both curious and unique in character, and many of them are particularly beautiful when in flower the closer they are studied the more fascinating they become. Small numbers of them may be kept among a miscellaneous collection of greenhouse plants, provided they are carefully watered and given a situation in full sun, but if it is intended to specialize and form a collection of succulents they will require a greenhouse to themselves. This also applies to a collection of orchids or ferns. To gain the maximum use and pleasure from a greenhouse, one or possibly two cold frames should be bought or constructed. Without adequate frame space it
is not possible to use a greenhouse to its full capacity. Some plants require a period in the cool atmosphere of a cold frame, either during the hottest summer months or when they are dormant and resting before being started into growth. When a greenhouse is used for raising young plants or producing summer bedding plants, frames will be invaluable for hardening them off, at the same time releasing space in the greenhouse for the cultivation of other plants. Another essential piece of equipment for the greenhouse is a propagating case for raising seedlings and rooting cuttings. Prototype propagation cases were glass-topped frames built over hot-water pipes and placed at the warmest end of the greenhouse. The introduction of electrical soil-warming cables has changed all this, and it is now possible to buy complete propagation cases with plastic domes to replace the glass, equipped with a thermostat and warming cables. Under these conditions, the correct degree of heat and humidity can be provided for the seedlings and young plants.
Some greenhouse plants are difficult for an amateur of limited experience to propagate, and in such cases it is recommended that young plants should be bought from specialist producers. The greenhouse space can then be devoted to raising seedlings and plants which can be grown successfully. A collection of choice alpines will add distinction to the greenhouse and bring untold joy to its owner. These plants do not require, nor will they tolerate artificial heat but, because many of them flower during the early months of the year, the fragile flowers appreciate the shelter of a glass roof. They do best in a greenhouse on their own one which has been specifically designed to give unrestricted access to all possible daylight and well equipped with ventilators to allow for the maximum amount of ventilation. Many gardeners prefer to use their greenhouses for growing fruit and vegetables.