Orchid Care Information
Orchid Care Information
The first orchid plants to arrive in Europe came from the West Indies in the mid-eighteenth century. These were of the species Bletia verecunda (purpurea), Epidendrum rigidum, various Vanilla species and Epidendrum fragrans. Later in the century came the first Asiatic orchids Cymbidium ensifolium and Phaius tancervilleae. Not until the beginning of the nineteenth century did orchids arrive from South America. Few orchids survived the long journey to Europe, but this only made them the more desirable. At first the cultural systems adopted contributed to the casualties. Irrespective of source, all orchids were kept in excessively hot, damp, humid conditions and poor light. It was a long time before it was realized that few orchids came from steaming jungles and that fresh air and cooler temperatures might bring more success.
Nowadays orchids are still imported but on nothing like the scale of the last century. This is due in part to nature conservancy and the restriction of exports, but even more to the production of hybrids. The first orchid hybrid, x Calanthe dominyi, between Calanthe masuca and Calanthe furcata, was made in the mid-nineteenth century by John Dominy of the firm of Veitch, and in 1859 he exhibited at a meeting of the Royal Horticultural Society in London five seedlings which were hybrids of Cattleya guttata and Cattleya loddigesii (x Cattleya hybrida). Gradually further hybrids involving other genera were made, frequently in a haphazard manner. In 1904 a breakthrough occurred. This was X Odontioda vuylstekeae, the result of crossing Cochlioda noetzliana with Odontoglossum pescatorei, the first bigeneric hybrid.
The production of hybrid orchids in quantity was limited by the symbiotic method of seed germination, which was the sowing of the seed on the surface of the compost of a healthy adult plant. Losses were heavy under this system. In 1922 Dr Lewis Knudson of Cornell University introduced an artificial medium, providing nutrition for the orchid seed chemically in a base of agar jelly (asymbiotic process), the seed sowing being done under laboratory conditions. This process revolutionized the raising of hybrid orchids, not only by enabling them to be produced in quantity, but because planned breeding programmes could be carried out. Knudson’s formula has been superseded by many variations of the original, particularly in the USA, Hawaii, S. Asia and Australia, where due to kinder climates most of the world’s orchid raising is now done.
Meristem propagation ()
When an orchid hybrid is registered, all the seedlings of the cross receive the same name, even though they may vary tremendously in many respects. Selected plants of the cross may then be given varietal names. Until the introduction of the meristem method of propagation, such plants could only be multiplied by division of the original plant, a slow business which kept prices high. Now, however, theprocess enables practically any number of identical plants to be brought to the flowering stage in 3-5 years, the time taken to produce a flowering seedling. Briefly this technique is as follows: a microscopic section of the growth tip of a young orchid shoot can be raised as if it were an orchid seed. If, however, the seed-raising medium is a liquid, ie without agar, and the medium constantly disturbed — the flasks containing the medium are placed on a rotating wheel — the original growth tip will proliferate. The proliferations are then sectioned and each section treated as the original growth tip. The process can be continued until the desired number of propagations is reached, the rotation is stopped and the sectioned proliferations will then develop into plantlets. These are then treated as orchid seedlings.
This method of propagation brings young plants identical to the world’s most illustrious orchids within the reach of everyone. Seed raising is of course still necessary, since only by this method can new and better orchids be raised. Tissue culture has not as yet been applied to all genera. It has, however, enabled commercial Cymbidium growers to upgrade their stock and amateurs to possess orchids which a few years ago would have been quite beyond their means.
Meristem or tissue propagation for amateurs is probably too difficult to carry out due to the equipment required, but in fact kits are available in America for this purpose though the original propagation is supplied ready for use. Seed raising is by no means beyond the careful amateur, since all the requirements for seed sowing are available in kit form both in Britain and in America and the simple equipment needed can readily be obtained. Raising the seedlings is more difficult than producing them, but temperature and light-controlled Wardian-type cases can be made or purchased.
Starting a collection of orchids
Until fairly recently prospective orchid growers experienced some difficulty in obtaining information of any kind on this subject. Nowadays more orchid nurserymen are advertising in the general garden press, most public libraries contain at least one or two orchid books, and the British Orchid Council means that it is only necessary to write to the secretary of that body to receive a list of orchid nurseries and of the orchid socieities in Great Britain, with one of whom an early contact should be made for advice. A further and most useful source of advice is your local botanical garden, where at least some orchids will be grown.
Specially designed orchid houses are obtainable, but orchids may be grown in any kind of greenhouse if certain points are borne in mind. Glazed to the ground structures, due to their high heat loss, are only really suitable for growing Cymbidium in beds of compost at ground level. Any greenhouse, however, may be double glazed to help with the control of heat and humidity. Preferably this should be done with one of the transparent semi-rigid plastics. Concrete is better avoided for the floor surface unless the house is naturally a very wet one. Ash floors will retain water and provide humidity.
Which orchids to grow?
This depends not only on personal preference, but on the average temperature of one’s greenhouse, particularly the winter temperature. While an occasional drop in temperature during severe winter conditions will do no harm, particularly if the house is kept on the dry side, there is no point in attempting to grow orchids at temperatures consistently below the optimum. Of the commoner genera, Cymbidium will do well at winter temperatures of 10-12.8°C (50-55°F), Odontoglossum at similar temperatures, Cattleyas and Paphiopedilumn at 12.8-15.6°C (55-60°F) and Phalaenopsis and Vanda at 18.3-21.1°C (65-70°F). With one of these as the main crop there are innumerable species available for each temperature range to provide variety.
The conditions required for growing orchids may be summarized as follows: adequate heating; shading from April to September, the amount depending on which orchids are grown and preferably provided by blinds; adequate fresh air combined with air circulation such as may be provided by an electric fan; a relative humidity of from 65 to 85% day and night, provided by watering the greenhouse by watering can, hose, or automatic mist spray system.
Watering is the key success factor in orchid growing. Many orchids require much water during the growing season and infrequent watering during the rest of the year. Much water with any orchid means pouring water through the compost until it is wet, then no more water until the plants require it—this is largely a matter of experience. It does not mean dribbling water every day until the compost becomesand the orchid roots die. Since in fact orchids in a humid atmosphere require less frequent watering than most other plants, their culture lends itself particularly well to the automatic provision of heat, humidity and ventilation. Even automatic shading is available, although rather expensive.
Modern potting composts have done away with the principal chore of orchid cultivation. Economy composts were introduced to replace expensive osmunda fibre and have proved to be not only less expensive but easier and quicker to handle and frequently they produce better growth. Bark composts are often used for Cattleya and Vanda, particularly in the USA, and most genera will do well in equal parts by volume of fibrous, lumpy peat, Perlite or polystyrene granules and sphagnum moss, the aim being to provide a compost which will hold plenty of water but at the same time remain well drained. Where available locally, sphagnum moss alone is quite a useful compost, particularly for Dendrobium and newly imported orchids. As economy composts are generally lacking in nutrient, a slow-release fertilizer such as Magamp or Vitax Q4 is generally used. Due to the relatively poor light in Britain, few orchids will respond to as heavy a fertilizing programme as they would in the tropics. Rockwool has now been introduced for orchid culture.
In botanic gardens many orchids are grown on pieces of bark or logs or in open teak or cedar baskets. Orchids may be divided into epiphytic and terrestial plants, the former normally growing on trees, not usually on the bare bark but in association with mosses and other epiphytic plants. Terrestial orchids normally grow on the ground. Most of the popular genera of orchids are epiphytic, but in the open composts mentioned will grow perfectly well in pots and these, if desired, may be hung from the roof of the greenhouse or on the walls. It may seem natural to grow epiphytic orchids without pots but such do require a great deal of attention to watering and spraying.