Growing Orchids In A Green House

When it comes to growing orchid in green house, 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 when it comes to growing orchid in green house.

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 in growing orchids in a green house, 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 when growing orchids in green house, 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 when growing orchid in green house, 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 when growing orchid in greenhouse, 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.

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.

When growing orchids in a green house, 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 se¬cured, 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.

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