Orchid House
This term is applied to any garden structure in which Orchids are cultivated, to the exclusion of all, or nearly all, plants of another description. It is not necessary, nor, indeed, always thought advisable, to relegate these plants to certain houses by themselves; but in nurseries, where space for thousands of living imported specimens have frequently to be found, and a large collection of established plants is also grown, not only are special Orchid Houses found necessary, but large structures are frequently devoted wholly to the accommodation of such genera as Cattleya or Odontoglossum alone. Nor is this system entirely limited to nurseries; many private collections have now become so extensive, in consequence of the frequent additions made, that similar arrangements are being adopted. Where large and varied collections of Orchids are grown, they are usually arranged, according to the amount of heat required, in three separate houses, or three compartments of one house having the heating arrangements fully under command. When only a mixed collection is grown, the several genera forming it must be afforded positions as favourable to their well-being as circumstances admit, and the temperature varied somewhat by giving a greater or less amount of ventilation in different parts of the house in which they are placed. The following are the names usually given to the three different Orchid Houses, or divisions referred to. Approximate temperatures for each, during summer and winter, are also subjoined, as a general guide for cultivators, and not with the intention of their being rigidly followed:
1. East Indian House. To this department are relegated all Orchids requiring the highest temperatures, such as those originally received from the Eastern, and also from the hottest parts of the Western, hemispheres. These plants need plenty of moisture in the air during their season of growth, and also a circulation of air, somewhat cautiously applied, to avoid sudden changes of atmosphere. Temperatures: Summer--day, 75deg. to 90deg., with sun; night, 70deg. to 75deg. Winter--day, 70deg. to 75deg.; night, 60deg. to 65deg. 2. Brazilian and Mexican House. This provides accommodation for Orchids which require an intermediate temperature, as, for instance, the bulk of the Mexican species and a number from Brazil, &c. These will succeed in a drier atmosphere, generally, than those already referred to, but shrivelling must not be allowed. Temperatures: Summer--day, 75deg. to 85deg., with sun; night, 65deg. to 70deg. Winter--day, 65deg. to 70deg.; night, 60deg.
3. Peruvian House. A division specially for cool Orchids, natives of the mountains of South America, India, &c., many of which never appear to have any fixed season of rest. They are best suited with a cool temperature, and a more or less genial, most atmosphere all the year round. Temperatures: Summer--day, 60deg. to 70deg.; night, about 60deg. Winter--day, 50deg. to 60deg; night, 40deg. to 50deg., according to temperature outside.
The shape of structure most suitable for Orchid culture, generally, is a span-roof, or something very closely approaching it, such as a three-quarter span. Lean-to houses, with northern aspect, are well adapted for all the cool species and varieties of such genera as Masdevallia and Odontoglossum, in summer particularly, as these do not succeed in a high temperature, nor in houses where, from sun heat or other causes, the atmosphere is dry at any time of year. Where the ventilation is properly arranged and managed, cool Orchids may be grown as successfully in a structure of another shape as in a lean-to. A span-roofed Orchid House, about 60ft. long, 12ft. wide, and 8ft. high, would accommodate a large quantity of small plants, which could all be arranged on side stages, near the glass, or a large number might be suspended from the roof. The side walls should be carried about 4ft. or 4 1/2ft. above the ground, and small doors or sliding ventilators inserted in them, about half-way up. The top ventilation should be effected by having a longitudinal flap, made to rise up from the inside, or by small sashes attached with hinges to the ridge, and arranged so as to open without admitting rain in wet weather. Running sashes on the roof, and side-sashes opening on a level with plants on the stages, should now be recognised as things of the past when new Orchid Houses are being constructed. If plants requiring various temperatures are to be grown in one house, a glass partition will be the most convenient way of dividing one part from the other, which might have more or less heat and air applied, as found necessary. The dimensions given above would only be suitable for a house in which small or moderate-sized plants were intended to be grown; for specimens of considerable growth, or for large collections, proportionate measurements to any extent might readily be taken to meet requirements. Side stages should be about 4ft. from the ground. A system of having a double staging is sometimes adopted with excellent results for Orchids, namely, a bed of ashes, shingle, coke, or breeze, is laid on slates, which are supported by upright iron pillars. This bed is continually kept moist, and an open woodwork staging is placed above, on which the plants are stood. In some of the best-arranged Orchid Houses, the plants stand over a water-tank, formed beneath the woodwork staging. Into this the rain-water from the roof is conducted, and is always close at hand for watering the plants. It is most important that only rain-water be used for this last-named purpose, if it can possibly be obtained. Orchid Houses should never be built so high that the plants, when arranged inside, will be very far from the glass, or situated so as not to receive a sufficiency of light, which the majority of them require. There are few Orchids, except, perhaps, the Mexican species, that are not benefited by shading in summer. This should not, however, be thick, neither should it be permanently fixed on the roof. A thin shading, sufficient to exclude bright sunshine, while, at the same time, admitting light, is best; it should be tacked on rollers, and kept up during dull weather. General Remarks on Culture, &c. The special cultural requirements of all the important genera of Orchids being given elsewhere in this work, under their respective headings, it will be unnecessary to add more here than a few brief remarks of a general character. At one time, Orchids were limited to the gardens of a comparatively few wealthy owners, who took an especial interest in them, and spared no expense in obtaining such plants. The same conditions exist up till the present, in respect of rare specimens, or those of exceptional merit; but some representatives of the more popular genera are, fortunately, now found almost everywhere. This is mainly the result of enterprise, shown by sending collectors of plants to remote foreign lands, where Orchids abound, for the purpose of seeking new additions to the species, or varieties, already obtained, and for transmitting, in quantity, well-known and popular kinds, for distribution in this country. The method of culture, too, has been much modified, since it was found that the plants, in general, did not really require so much heat as what was, at first, thought necessary. Orchids are able (especially many of the strong-growing species) to withstand a considerable amount of ill-usage, compared with many other plants; otherwise, so many thousands would never reach this country and re-establish themselves in the way they do. Heat and moisture afford nearly all the plants need, consequently, the proper method of applying these is, at least, one of the main points in successful culture. Good fibrous peat, living sphagnum, and charcoal, form the principal materials necessary for the majority of Orchids. These are of more use for holding the plants in position, and retaining moisture for the encouragement of the tender roots, than for any particular nourishment afforded. It is remarkable how some attach themselves to a block of wood and succeed admirably with nothing else, save a little sphagnum and the proper attention in watering. Pots for Orchids should, with few exceptions, be quite half-filled with clean drainage, and they should be used as small as possible, in proportion to the size of plant. Shallow pans, made in various sizes, either for suspending from the roof or for standing on stages, have been used very extensively of late, with most excellent results. Orchid baskets should be made of teak wood, as it is hard, and lasts a long time. They may be purchased in several sizes, ready for use. Blocks, or rafts, may also be made of teak, or pieces of tree-fern will frequently answer equally well. A moist atmosphere is most desirable for all during the summer, or growing season, and, as a rule, plenty of water at the root. The amount of rest necessary varies considerably, and can only be properly apportioned by experience with different genera or species; some (as already remarked) are seldom completely at rest. Heavy syringing is not recommended at any season: a very slight dewing over the plants may be advantageous in summer; but, further than this, the use of a syringe should be limited to distributing water amongst the pots for moistening the atmosphere. Cleanliness amongst Orchids, in every respect, is one of the main roads to success. Dirt on the plants, or the pots, in the drainage, or even on the beds beneath, will soon produce an evil effect on the healthy appearance that should, and generally does, characterise Orchids receiving proper attention.
Insects, &c. Orchids are subject to many insect pests, and to a much-dreaded disease called the "spot." This latter is considered to be encouraged, especially in winter, by a superabundance of moisture and by a stagnant atmosphere. White and Brown Scale, Mealy Bug, Yellow and Black Thrips, Red Spider, Yellow and Green Fly, are all included in the insect pests to the attacks of which the plants are at times liable. Sponging with weak soft soap or tobacco water is recommended for eradicating any of them: fumigating Orchids is a practice not to be approved of, as it undoubtedly causes injury at times. Cockroaches, Slugs, and Snails, must also be included amongst the enemies of Orchids.