From the time of acquiring his first plant the beginner in orchid culture must learn much that is new and, perhaps equally impor­tant and difficult, unlearn much that applies to growing other plants. For successful growth the orchid, like plants of the garden variety, requires a proper balance of light, heat, water, and food. The proportion and quality of these elements are, however, radi­cally different for the orchid.

Most epiphytic orchids come from tropical or subtropical re­gions where there is abundant atmospheric moisture and where the intense sunlight is modified by dense foliage. Showy tropical orchids, dwellers in rain-swept jungles, cling to trees and send out long roots, seeking nourishment from moisture-soluble minerals in the air and from humus in the forks of tree trunks. Other orchids grow on bare rocks, where they are subjected to drench­ing rains and drying winds. The sun in the regions where such orchids grow is tempered by the constantly drifting clouds that bring the sudden showers. In transplanting orchids from their diverse habitats to civilization the grower is faced with a major problem—suitable housing.

There are some fortunate regions where housing presents little or no difficulty. Hawaii boasts few or no indigenous orchids (opinions differ on the matter), but the climate makes it possible to hang imported orchids in trees, with happy results. Australia has many native orchids and many localities accommodate im­ported orchids in bush-houses, the equivalent of American lath-houses. On the island of Ceylon and in some other tropical coun­tries a large foliaceous tree in the garden makes a splendid home for many types of orchid. Central and South America are the habitat of many of the finest members of the orchid family, and gardens abound in them. Even there, however, scale and other pests must be kept under firm control. Regions with a climate similar to Southern California are ideally suited for growing, under lath, genera such as Cymbidium.

The climate of the major portions of North America, England, and the Continent, however, make some sort of heated glasshouse necessary. The balance needed by the orchid, although peculiar and exacting, can be provided if the requirements are understood and provided for by the grower. The task is to provide conditions paralleling those of the plant's native habitat, and to substitute others when the natural environment cannot be approximated. The success of this procedure is demonstrated by the fact that many species grown in the glasshouse are far larger and more beautiful than jungle-grown specimens.

Natural conditions of temperature, atmospheric humidity, sun­light, and free circulation of air must be reproduced for each spe­cies of orchid plant under cultivation if maximum production and quality of blooms are to be attained. This requires some sort of enclosure where each component of the balance can be properly controlled. There is perhaps no perfect answer to the problem of housing. Each grower, guided by the experience of others, must find a solution according to his needs, desires, and resources.

Occasionally someone will describe, with contagious enthu­siasm, how he has grown orchids on the window sill of a kitchen or sun porch, and has even brought them to full bloom. It can be done. Success depends on the ingenuity of the grower in impro­vising means for balance. Some amateurs have attained a measure of success by adapting a heated glass-enclosed porch. Others have grown plants in the home over open pans of water resting on shelves in front of large windows. But it must be emphasized that only the most vigorous types of orchids will thrive or even live under such conditions.

The Wardian case is a solution of the orchid housing problem for apartment-house dwellers and people living in congested areas. It may be a glass case, frequently piano-box shape, about twenty-four inches by twenty-eight inches and from twenty-four inches to thirty-six inches high, provided with a thermostatically con­trolled heating system (an electric-light bulb, an electric coil under the gravel of the tray, or even a brooder element will serve), with a water-tight pan covering the bottom to hold water or moist gravel to humidify the air, and with a means of controlling the ventilation (a hinged front may be used for such aeration). Addi­tional moisture is sometimes secured by laying lamp wicks on props with one end in the pan of water on the floor. An all-glass floor-type showcase may be readily converted into a Wardian case. More elaborate cases, specifically designed for orchid culture, are produced by several manufacturing firms. For the amateur who wishes to grow only ten or twelve blooming-size plants or who requires an incubator for orchid-seed culture and for growing seedlings in community pots a properly constructed Wardian case gives excellent service.

Now, although the owner of a Wardian case at first proclaims his satisfaction, it is the very nature of an orchid grower that sooner or later he should begin to yearn for a greenhouse. The greenhouse is essentially a glass-covered structure (into which the grower may easily walk standing erect), equipped with the means to control ventilation, temperature, humidity, and sunlight. The range of choice extends from the lean-to (using the wall of a dwelling as a common wall) and the simple amateur greenhouse to the conservatory with a lofty arched roof and the neat rows of trim commercial houses called ranges.

Before making a final decision in regard to the type and size of house, the amateur will be well advised to pause and consider his needs and his ability to meet them. He should look ahead as far as possible, to build for tomorrow as well as today. Many an amateur has rushed headlong into building only to find that many costly mistakes might have been avoided if he had put a little thought and study into planning.

One thing, aside from burning enthusiasm for his hobby, sets the orchidist apart as different and perhaps a trifle eccentric—his terrific acquisitiveness. Today he has one plant, the next day someone offers him a backbulb from 'my very best plant.' He repots and divides what he has, indulges in a community pot of fine seedlings, trades here, buys there, and finally takes a chance on importing a hundred or more species plants. Before he is aware of what is happening the single plant has grown to a collection that is not small. Almost overnight his orchid-housing needs have become unexpectedly complex. If this contingency is not foreseen the house will be outgrown before it has been completed.

It is difficult, as in all branches of orchid culture, to set down any hard-and-fast rules about the size of the greenhouse. This must be determined strictly by individual needs. Ideally one square foot of bench space per plant is desirable. Orchid plants vary greatly in size; they grow in containers ranging from thumb pots to large tubs, so that their space requirements differ. In gen­eral the plants in an amateur's collection will require from one-third to one square foot of bench space, with additional space allowed for future acquisitions. It might be safe to say that a nine by twelve house can be made to hold about 150 plants with­out too much crowding. The overcrowding of plants must be considered seriously, for overcrowding brings trouble in the form of pests, disease, and spotted flowers owing to poor air. The need of orchids for free circulation of air cannot be over-emphasized.

In the last analysis, the size of an orchid house will be deter­mined by the very practical considerations of available space, the amount of money the grower can spend, and the number of plants to be housed—either now or in the future. Advantages of a small house are ease and economy of construction and maintenance. A somewhat larger house allows superior heating and ven­tilation control, with better air and less crowding.

Sample measurements for an amateur house might be fifteen by thirty feet with a ridge nine to ten feet high, the roof with a pitch of about twenty-six and a half degrees, aisles not less than two and a half feet wide. The benches may be thirty to thirty-six inches high—the exact height governed by the comfortable reach of the grower. A thirty-six-inch bench on each side of a three-foot walk requires that the house be at least nine feet wide; a five-foot middle bench can be added if the house is sixteen feet wide.

After size, the next consideration in the plan is location, which will probably be dictated by elevation and the contour of the ground. The house should be so located as to provide the most sunshine. Shade can be attained by any number of means, but the right light comes only from the sun, for which there is no substi­tute. Contrary to popular belief the orchid is a sun-loving plant. It may exist, and even grow, without sun, but without an ade­quate amount of sunlight it will not bloom. The needs of the different genera extend from well-diffused light to full sunlight. For this reason a location should be chosen where plenty of sun is available. The amount can then be regulated by artificial means.

There has been much controversy over the relative merits of north-south versus east-west facing. There is no principle involved here—the facing that gives the most sun is the best; but again the contour of the ground is a determining factor. The problem of facing is not of great importance with a small house, since it is so nearly square, but the sun's path over a larger house should be considered. Trees shading the location should be kept well trimmed to let enough light through. Deciduous trees make excel­lent shade, for they are more or less bare in seasons when the sun is weak while their full summer foliage coincides with the period when the sun's rays are strongest.

It is not necessary for the lot to be level. The greenhouse may be raised on piers to compensate for a hillside or it may be built in tiers with steps between. The foundation proper, however, must be level and firm. A good, level concrete foundation pays dividends in insuring firmness. Settling causes cracks in the glass; cracks cause dripping; and drippings make for spotted flowers—the grower's tragedy. Additional firmness can be gained by sinking eight- to ten-inch bolts into the wet concrete of the foundation, and then bolting the mudsill into place.

The next choice facing the amateur is between the home-built house and the many available sectional, ready-built greenhouses. Prefabricated houses, while possibly more expensive, are easily erected and may save money by eliminating the mistakes preva­lent in the trial-and-error method of design. There is the addi­tional advantage that prefabricated houses are movable, being bolted rather than nailed together. Greenhouse manufacturers supply detailed plans and all materials for houses to be erected by the grower or a carpenter.

There are many types of design, but the most economical and satisfactory is the so-called 'even span' type where the roof slopes uniformly down from both sides of a ridge to the eaves. This slope should never be less than six inches vertical to one foot hori­zontal; a lesser slope will invariably cause leakage during rainy weather, and, instead of running down the glass, condensed mois­ture will drop from the glass on to the plants below. If conden­sation grooves are milled in the sides of the bar supporting the roof glass, moisture condensing on the glass will be drawn off and destructive dripping prevented.

A lean-to construction, with the greenhouse attached to the building along the high point of the glass roof, is sometimes necessary. In this case there are certain difficulties to be over­come. It is difficult to make strictly weather-tight joints between a lean-to and the building that forms one wall. It is often ad­visable to use a standard construction with one end attached to the building and with the ridge at right angles to the building, as this minimizes the difficulty of flashing at the building connec­tions. It should be borne in mind that the six-inch to one-foot roof pitch must also be provided for this type of greenhouse.

The best of construction plans may be frustrated by selection of unsuitable materials. Orchidists of Europe and the British Em­pire have shown wisdom through their long orchid-raising expe­rience by selecting only the most durable materials for greenhouse construction. Materials must be durable and suitable in relation to the specific conditions necessary for orchid growing—again the balance of heat, humidity, and ventilation. From the days when the name 'stove' was first applied to the hothouse, brick has been favored for sidewalls, not only because of its durability but equally because it holds the moisture and stays cool in summer and warm in winter. Cement, while not so popular, is almost as satis­factory and not so expensive. The continuous moisture conditions the choice of material for the frame and equipment. The wrong wood will rot and unprotected metal will rust. Pine and other soft woods are definitely not usable, as many a misguided ama­teur, with his house disintegrating about him after a few short years, has found. The constant damping necessary for the health of the plants causes rapid rot in the softer woods. On the Pacific Coast the availability of redwood, with its resistance to damp and abuse, makes it the wood of choice. In the East and Midwest, Red Gulf cypress is favored for the same reasons. All metal used should be hot-dipped galvanized steel or brass in order to mini­mize corrosion.

While the nine-foot wide, two-bench greenhouse does not ordinarily require additional framework to support the roof, houses wider than this must be more substantial to carry the additional weight, prevent sagging of roof bars, and resist wind. Galvanized steel pipe or structural steel is preferred for this pur­pose. Where the initial cost is the main consideration, wood may be used, but it has a poor appearance and is likely to sag.

Roofing glass should be new and of good grade, since poor glass may interfere with the quality of the light. Single-strength glass is suitable for use on the Pacific Coast or other localities where there are no snow loads or high winds to be guarded against. Double-strength glass should be used in more severe climates.
 
Glass can be used in sizes from sixteen by eighteen inches to eighteen by twenty-four inches. It should be installed by being laid with lapped joints similar to those of a shingle roof, except that the laps between should be only one-eighth to one-fourth of an inch. Wider laps are not advisable because the capillary action in the space between the lapped surfaces will cause leakage.

In glazing the roof, beds of putty should first be placed on the glass rabbets of previously primed wood roof bars, and the glass pressed into the putty so that the entire space between the glass and the bars is filled with putty. After each pane has been set in place it should be secured to the bars by means of zinc glazing nails: one nail at the bottom to prevent the glass from slipping down, and two more nails driven into the bars at either side to hold the glass firmly to the putty. After the glass has been se­cured, excess putty can be cut away flush with the glass inside and outside. It is poor practice to 'face putty' or place fillets of putty along the outside joints, as is usually done in glazing a window sash in a building.

Any first-quality outside paint may be used for painting the greenhouse. There is only one variation from standard practice in exterior painting: it is well to run the paint over the surfaces of putty and about one-eighth of an inch on to the glass in order to prolong the life of the putty. It might be well to varnish the putty and let it dry before painting. Paint to be used inside the green­house should be selected with caution. It should be known to be non-toxic to the plants. The constant damp makes anything soluble. Plants are so sensitive and the possible damage so in­sidious that the amateur is warned not to use any doubtful paint. Deleterious effects on orchids may not show up for six months to a year.

In the discussion of the plan so far, provision has been made for maximum sun. There is still the problem of controlling the intensity of the sun, which is again a matter on which intense debate rages among orchidists. The plants demand sun, but only experience will enable the grower to steer the fine course between enough sun and the excessive amount that will burn.

Generally speaking, the greenhouse glass may be kept clear for only a few weeks in mid-winter. At all other times it is necessary to provide shade of one sort or another, both to avoid excessive temperature and to prevent burning. An attempt should be made to approximate the degree of shade found in the natural habitat of the plants, where sunlight is filtered through layers of jungle growth. The cheapest and easiest method of shading is to paint the glass on the exterior with some mixture that admits consid­erable light and that may be easily removed in the late fall to admit clear sun in winter. Either a mixture of white lead and gasoline or a white casein paint that will wash off is satisfactory for this purpose.

A much more satisfactory shading is secured by means of lath slats supported eight to twelve inches above the roof surface. Most orchid plants thrive best in the kind of shading provided by laths, where moving bands of sunlight alternate with bands of shadow. Anyone who has seen orchids growing in the tropics will remember that effect of the sun. The slat shading also efficiently moderates greenhouse temperature on blazing summer days. An adjustable type of slat shading has been developed that varies the amount of shade to suit the season and can be removed easily for clear glass conditions in the winter (see page 39).

Some growers take an extra precaution against burning by tack­ing cheesecloth or sheer muslin about three inches below the ceil­ing inside. There is some disadvantage in this procedure, how­ever, since the damp cloth furnishes an almost ideal place for the growth of fungus.

The important matter of aeration is next to be considered. Proper circulation of air is essential for the health of the plants. Under natural conditions drying winds keep the epiphytic roots sweet at all times. 'In captivity' the orchid roots are confined in pots and baskets, and the air of the greenhouse can easily become 'dead' and stuffy. Air-conditioning would seem the ideal solu­tion, but the grower must be mechanically inclined and ingenious enough to invent a system of his own, for the few available ready- made systems are prohibitively expensive. Fortunately a well-planned ventilation system can bring the desired result except in extremely dry climates, and even in such localities a proper bal­ance between heat and moisture can bring a workable solution.

Vents placed along the roof ridge will provide sufficient air cir­culation. The openings should face away from prevailing winds, since a gentle movement rather than a draft is required. The openings may be operated by pushrods or the more elaborate worm-and-gear mechanism. Vents must overlap the openings to keep out rain and snow, and they should be screened against in­sects. Greenhouses are often equipped with bottom vents, but these are seldom used except in the case of certain genera like Cymbidium and Odontoglossum. Only experience will give the grower an understanding of the kind of aeration that is best for his particular collection in his particular circumstances. It is sur­prising how quickly, with conscientious observation, the grower comes to recognize the needs of his plants.

The major furnishing of the greenhouse interior is some kind of bench or table to support the plants. If certain basic require­ments are fulfilled, the exact type of bench or staging is up to the individual grower. Such stagings are, of course, subject to severe moisture conditions and should be built of durable wood, such as redwood or cypress, or other materials that will resist deteriora­tion. Cement is sometimes used but it lacks the advantages of drainage and aeration of the wood-slat type of bench.

Slat-deck or table-type benches may be built of boards or of one by two inch slats placed % of an inch apart. Some growers use a double-deck bench. The lower deck holds water-absorbent gravel, coke or Haydite for humidifying purposes. Over this there is a slat deck for plants supported by galvanized-steel pipe legs. The tiered bench, built like steps with eight-inch treads and risers, has the advantage of accommodating about ten per cent more plants per foot of floor area, but the grower in watering with this arrangement must be prepared for difficulty. Benches that are to hold small pots should have a raised rim to prevent plants from being knocked to the floor.

Insect-proofing of the greenhouse is vital, as anyone who has seen the depredations of pests among orchids can testify. Benches should be set a short distance from the wall and the legs may be set in some kind of holder—a cement form or even a Pyrex bak­ing cup—containing insecticide. Scale and fungi have a diabolical tendency to attack the part of a plant against the wall and out of reach—hence the warning that benches should be 'reach' width.

Floors should preferably be raised a few inches above the sur­rounding ground to provide drainage. One or two inches of gravel over earth (round or pea gravel is most satisfactory) makes the best type of floor, since it dries out quickly on the surface while retaining moisture underneath. Such a floor helps maintain proper humidity when it is wet down on hot days.

Walks may be of brick or rough concrete. Durable wood walks are more comfortable to stand on and, if constructed of slats, will dry out rapidly enough. They do, however, provide hiding places for slugs and other pests, including rats. Aisles between benches should be wide enough so that one may walk comfortably with­out fear of breaking off new shoots, damaging flowers, or knock­ing down pots.

Heating is perhaps the most vexing problem concerning orchid housing. Fear of heating failure, which may leave orchids exposed to the disastrous cold of freezing weather, causes the sleepless nights of many an orchidist. One amateur has gone so far as to have an alarm bell rigged up in his bedroom to warn of any heat­ing failure. Most of the worry can be avoided if enough thought goes into a heating plan well in advance of construction. Visits to the houses of other growers, discussions with them of the merits of different systems, conferences with a local plumber or heating expert, and investigation of available material will be worth all the time and effort so spent.

II i. Cattleya velu-tina. Brazil (Al­berto Perez; cour­tesy Orchid Digest) II 2. Brassavola no-dosa. Central Amer­ica (Alberto Perez; courtesy Orchid Di­gest)

II 3. Oncidium Forbesii. Brazil (Harry Blossfeld; courtesy Orchid Di­gest) II 4. Odontoglos-sum grande. Guate­mala (L. F. Haw-kinson; courtesy Orchid Digest) II. 5. Miltonia vex-illaria. Colombia (O. O. Uhle; cour­tesy Orchid Digest) II 6. Odontoglos-sum citrosmum. Mexico (Courtesy Orchid Digest)

Ill Dendrobium Farmeri. India, Burma (Courtesy Orchid Digest)

IV i. Cycnoches chlorochilon. Colombia (L. F. Ha' kinson; courtesy Orchid Digest) IV 2. Lycastc brevispatb syn. Candida. Central Amt ica (A. B. Willoughb courtesy Orchid Digest) IV 3. Phalaenopsis stuartiana. Philippine Islands (R Davis) IV 5. Coelogync Huettncriana. Burma (Alex D. Hawkes; courtesy Orchid Digest)

IV 4. Vanda coernlt North Indi a, Burn (O. O. Uhle; courte Orchid Digest) Philippine   Islands   (A.   B.   W longhby;  courtesy Orchid Digea IV 6.    Dendrobium    superbui Philippine   Islands   (A.   B.   W longhby;  courtesy Orchid Digea

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