The tropicalwhich are cultivated in artificial conditions in greenhouses all over the world require, for their well-being, growing conditions approximate to those in their natural habitat. The three most important factors are heat, light and . For nearly as long as have been grown in greenhouses, since the beginning of the nineteenth century, many have also been successfully cultivated as houseplants. There were early Victorian growers all over the British Isles, and later many highly successful growers in northern Europe, including Finland, Sweden and Germany and, of course, many more in the warmer parts of southern Europe and in the USA. All these enthusiasts had succeeded in producing growing conditions good enough to enable the plants to thrive and to flower, in living rooms.
It was naturally found that some orchids were easier than others to grow in a living room, just as some are easier than others to grow in a, and over the years the ‘difficult’ subjects have given way to the easy. The local climate has a great bearing on the types of orchids to grow; for instance, the varied and glamorous types cultivated in Singapore, with its high day and night temperatures and its very high , could be grown in the temperate zones only at great cost but would be found easy in, say, Florida. The dice, however, are not entirely loaded in favour of Singapore and Florida, for there the orchid fans find it difficult to grow and flower some of the orchids so in Europe and the northern part of the US.
With the coming into general use of central heating of the different types, the control of temperatures has become more precise. In addition to being able to adjust the day-time temperature by setting a thermostat, the night time temperature can be, and usually is, lowered for the sake of economy.
This lower temperature during the hours of darkness is exactly what most orchid plants need to function properly. It was achieved automatically in the old days by the simple fact that solid fuel fires were allowed to die down or to go out altogether at night, to be re-lit in the morning. Heating during these days is the most expensive overhead of a greenhouse, but orchids grown in a living room cost nothing extra, for most orchids suitable for home growing like the same temperatures as are appreciated by humans. With a little ingenuity the question of humidity sufficient for the plants can be answered, and this humidity need not create mould on the fabrics, the curtains, carpets and upholstery or upset the fine tuning of a piano. The aim is to create a little local climate for the plants while at the same time allowing the rest of the air to be healthy and dry for the people living in the room.
The simplest method for a single plant, or two or three small plants, is to find a wide and fairly shallowsuch as a bowl. Inside this is spread a layer of shingle (gravel), sand or some other substance which will retain moisture. The depth may be 2.5-5cm/1-2in and the material is thoroughly moistened. An inverted flower pot is then put on this, the orchid is set on the inverted pot and the bowl is then sited in a convenient place, near, for instance, a radiator. The effect of the warm air from the radiator on the moist shingle in the bowl is to vaporize it slowly. This vapour moves upwards past and through the plant’s thus providing the essential humidity for the plant. Radiators are frequently situated under a window and a windowsill would be a good place for the plants, provided precautions are taken to ensure that the sunshine in summer is diffused before it strikes the plants. A north-facing window in summer and a south-facing one in winter would be ideal. On cold winter nights, move the bowls from the windowsill into the room if there is any risk of frosty draughts coming through the window.
In the tropics, where the orchid plants now grown commercially originated, the hours of daylight are about 12 a day with an equal number of dark hours. For indoor growing in temperate zones this is not so necessary and provided at least 10 hours of daylight can be given, this will be enough. During the winter, of course, the few daylight hours can be extended by a mixture of fluorescent tubes and incandescent bulbs, in the relation of nine watts of fluorescent to every one of incandescent.
When choosing the kinds of orchids with which to start one or two things must be considered. Firstly, of course, the plants should be easily cultivated and obtained at a price within easy range, and the space or spaces available and the necessary height should be taken into account. Some orchids are too tall except for the largest kind of window alcove or for siting in a corner to give them room. Then there is the question of colours. Practically every colour except blue is to be found somewhere in the orchid family, and even blue is found in Vanda caerulea, one of the plants which grows very well in Singapore and Florida but is not so easy in northern conditions.
Further points to be considered are the period in the year of flowering and. The plants should be chosen for flowering when the family is at home to enjoy them, and not while they are on , and the will depend on the availability of material. It is best to obtain special orchid soil mix from the supplier of the plants; very few commercial suppliers really appreciate being asked to supply it for one or two plants purchased from somebody else. nurseries usually supply the special type of soil mix needed for orchids. Epiphytic orchids are grown in an open soil mix of two parts osmunda fibre and one part sphagnum moss, but terrestrial species should be grown in a more loamy soil mix of equal parts peat or leafmould, loam, sand and moss.
The price to be paid for beginner’s plants depends mostly on whether they are hybrids or species. Hybrids, if raised by the supplier, have cost him higher and higher overheads for five to ten years, which is roughly the time it takes to flower a cattleya or many other genera from the moment ofthe . Even the seed pod requires a year to ripen. Fortunately, however, the growing use of the new meristematic method of is bringing the price of orchid hybrids down by greatly shortening the time needed to produce them in large quantities.
Species are imported direct from the jungles of the world, and although some are very expensive because of rarity, on the whole they are less expensive than hybrids, having been bought ‘ready-made’ from a dealer who has only collecting and transport charges to pay for. These plants require careful treatment on being received and some take a long while to recover. There are, however, many commercial orchid growers who import species of various kinds, and who retail them to the public only when the plants are well established. These are to be preferred by the beginner, but they are a little more expensive than those brought direct from the jungle.
It seems very likely that species previously inexpensive will become less easy to import because of recent legislation. The UK and the US are among the nearly 60 signatories to the 1973 Convention on Trade in Endangered Species of Wild Fauna and Flora. A few orchids are on the ‘endangered’ list and all others on the ‘vulnerable’ list. The endangered cannot be imported for trade; the others must have an export permit from the country of origin and the importing country must have an import permit.
A brief description of the life of an orchid hybrid may be of interest. Firstly the hybridizer selects two plants for parents of the new hybrid, removes the pollen from each and transfers it from one to the other. At the end of a year, more or less, the seed pods have matured. They are then taken from the two plants and sown on the surface of an ‘agar slope’ in flasks or test-tubes in hygienic conditions in a laboratory. After a few months the seed, which is very fine, has germinated and is ready to be taken from the flasks to be pricked off on to the surface of a small pot containing the appropriate soil, 20 or 30 plants to a community pot. After a further few months these tiny plants have increased in size sufficiently to be transferred to another pot, but this time only four or five of the young plants to a pot.
They remain here for a year or so by which time they are now really growing up, although only about half way to maturity. A further move or two will take them to the large pot in which they will flower. Some will flower after five or six years, others during the following year or two, but there will always be some which will not flower for eight to ten or so years after sowing. These frequently turn out to be the finest varieties.
Some orchids go through a resting period after flowering when they make no active growth and often lose theirand . During this period, very little water or humidity should be supplied.
ORCHIDS FOR THE LIVING ROOM
The two criteria for home growing are: is it easy and is it available? Among the over 20,000 species of wild orchids and 100,000 hybrids it would seem there are plenty from which to choose. The following, however, although only a tiny fraction of this huge number, meet both criteria. There are many others equally suitable for growing indoors, but to mention them all would be impossible and would result in only a catalogue.
Cattleya 10°C/50°F min; Mexico to Southern Brazil
The most striking of all orchids for size and colour is by general consent the cattleyas. This group contains other genera very similar in appearance to the cattleyas but which are botanically different and which have been interbred with each other to make multi-generic hybrids.
There are a great number of cattleya species and a vast number of cattleya hybrids. Depending upon the pedigree, the hybrids show a great variation in colour, from pure white to deep purple, most having several different colours in their various segments and also, depending on their genetic background, a great difference in size, an important consideration for home orchid-growers. Recommended species of cattleyas .are C. labiata, which gave its name to a whole group of unifoliate species and which has a single thickand 23cni/9in bearing large rose-coloured blooms with a frilled crimson lip and yellow throat in autumn; C. bowringiana, at 60cm/2ft rather too large except for a room with exceptional height, has several rose-purple, yellow-throated blooms from September to December; C. aurantiaca, a multi-flowered small plant, orange-red in summer. Allied genera include Laelia anceps ( -rose blooms), L. gouldiana (rose-purple) and L. purpurata (white and deep purple with veined yellow throat), a favourite among Brazilian growers. Sophro-nitis uniflora (syn. S. grandi flora), a small brilliant red orchid, was intercrossed many generations ago to produce warmer colours in multigeneric cattleyas. Brassavola digbyana is another orchid in the cattleya family, noted for its magnificent fringed lip.
Cattleyas generally are lovers of light, but in common with most orchids do not appreciate full summer sun through glass, and so must be either shaded or removed to a situation away from direct sunlight. They also prefer plenty of humidity and water while they are growing and should be repotted when they become crowded in the pot. Propagate by division.
7-10C/45-50°F mm; Ceylon to India and Japan/Malaysia to Australia
This is probably the most popular cool-house orchid and is grown outside in such favoured climates as those of California and New South Wales. For living room conditions, however, most species are probably a little too large, but miniature hybrids, a comparatively recent trend, are suitable. They originate from C. devonianum from the Himalayas and C. piuiii-liini from China and Japan and have erect or arching flower sprays in almost any shade, self-coloured or flushed, in spring and early summer. Shade from strong sunlight in summer. Repot every year after flowering. Propagation is by division.
Miltonia Tansy Orchid; 10°C/50°F min; Tropical America/Brazil
There are two main kinds, those originating in Colombia, the more popular at present, and those from Brazil. The Colombian hybrid miltonias are derived from M. vexillaria and M. roezlii, the last of which is difficult to obtain. There are many hybrids with narrow leaves and pansy-like, in brilliant colours, ranging from white, through rose to deep red. There are several blooms 9cm/3jin wide on each 45cm/18in spike. They require shade during the summer, when they flower, and good winter light. Keep the soil moist and repot every two or three years. Propagate by division of the pseudobulbs. There are also now quite a number of Brazilian hybrids, different in general appearance from the Colombian types, and some attractive species, best of which are M. spectabilis ‘More-liana’, a dramatic bloom, and M. regnellii with rose-pink and yellow flowers.
10°C/50°F min; Central and South America
Cool-growing, shade-loving and having long-lasting flowers, this is a most attractive genus. Many species are still easily obtainable and there are great numbers of odontoglossum hybrids, mostly from O, crispum. There are about 300 species found in higher altitudes in Central and South America, and in particular Colombia. In a living room they require a cool, moist, buoyant atmosphere; consequently they will do best in some form of container near a ventilator and lightly shaded. O. crispum is the best known, with its 60cm/2ft long flowering stem of numerous white and pink blooms in spring; others are O. bictoniense (brown and pale rose), O. cervantesii (white or pink with chocolate-brown lip), O. insleayi and O.grande, the largest flowered of all odontoglossums, being yellow-striped brown. Propagate by division.
Oncidium 10°C/50°F min; Central and South America
There are more than 700 oncidium species, many of which have been used in hybridizing. Although most oncidium species have leaves about 30cm/1 ft long, the flower spikes are usually even longer, often .9-1.2m/3-4ft. One rather more modest species is O. ornithoryn-chum whose flower spike is 60cm/2ft high and sometimes even smaller. The branched flower spikes arch or droop with numerous small blooms, yellow or brown, and usually appearing in autumn. Treat oncidiums as odontoglossums.
Paphiopedilum Slipper Orchid; 13°C/55°F mm; Tropical Asia
For many reasons this genus is the odd man out, but as far as cultivation is concerned the most significant differences are that it is usually a terrestrial orchid, most others being epiphytic, and that it has no pseudobulbs. These two points are probably co-related. because, growing on the ground, it has access to nutrients in the soil and so does not need the pseudobulbs common to most epiphytes. This is the orchid which also goes contrary to the general rule that orchids should not be watered except when dry, for paphiopedilums need to be pleasantly moist at all times, with plenty of humidity and shade during summer, and fertilizer from May to September. The 40 species are widely distributed over the Far East, and the hybrids run into thousands as this was a genus much used very early on in hybridization. The hybrids are almost invariably shade-loving; they are very tidy-growing and the blooms are long-lasting. These are conspicuous by a large slipper-shaped lip rising above two petals and a dorsal sepal. Colours vary from yellow through green and brown to purple, and the slipper is often veined or striped. Flowering time is throughout the year, depending on the type. Propagate by division in the spring.