Most people regard orchids as plants which require special cultivation and understanding. This is certainly the case, but even amongst the greenhouse orchids, there are wide differences in their needs, and some of the most decorative of the orchids that are grown under glass can be cultivated in an ordinary cool greenhouse. Among these are the Cypri-pediums or Slipper flowers.
One of the chief points to consider in the cultivation of orchids is the preparation of congenial soil. In nearly all cases the addition of sphagnum moss to the compost is advisable. This allows the soil to be kept moist without any danger of sourness.
In the case of opiphytal orchids the best soil is a mixture of fibrous loam, osmunda fibre, sphagnum moss and dried leaves, and this mixture can be taken as suitable for the majority of greenhouse orchids whether terrestrial or epiphytal. Apart from differences in temperature, most of the greenhouse orchids require somewhat similar treatment.
There are two classes – terrestrial and epiphytal – the first of which is grown in pots of soil, while the other class is grown in hanging baskets or on blocks of wood. When hanging baskets are used, they should be made of teak for durability. The moist atmosphere in which these orchids are grown will quickly cause decay if soft wood is used.
It is not possible to give full general instructions which are applicable to every class of orchids, but apart from the special soil already recommended, great care must be given over the ventilation and watering.
A moist, humid atmosphere is needed for most orchids and to maintain this the plants and the staging should be sprayed frequently. Most of the plants have a resting period after the flowers are over, during which a slightly lower temperature and less moisture may be given.
The amateur who is beginning the culti-vation of orchids will, however, find it best to ask the nurseryman who supplies the plants to give him some indication of the type of treatment they require. He should also remember that it is not always sufficient to have one separate house for orchids, but that if orchids of many different types are to be grown two or three houses, that can be kept at varying temperatures, are required.
For cool cultivation, where only one house is available, the best types of orchids to select are: Cypripedium insigne, Oclontoglossum crispum, and Masdemllias. In a slightly higher temperature Catlhyas and their hjbrids can be grown and will succeed with ordinary care.