V Vanda Sanderiana. Found only on Mindanao, Philippine Islands (Harold Johnson)

VI 1. An amateur's orchid house with gravel floor double-deck wall bench stepped center bench Wardian case for seedling at rear

VI 2. Double-deck orchid bench construction

VI 3. Wardian case used orchid seed culture (F Bams)

VII 1. Slat shading (for description see page 39) (I.. F. Hawkinson; courtesy Orchid Digest)

1. Side-view slat shading (J. J. Wilson; courtesy Orchid Digest)

/II 3. Sketch of heat-ng plant (for descrip-ion see pages 37-8) Lee Brooks and J. J. Vilson)

SHOWING HOW LADDER. RESTS  ON  2  GLAZING BARS (I)   CHICKEN   LADDER. (7) VENTILATOR

VIII The chicken ladder (Jeanne F. Brown)

Any orchidist who has used an ordinary ladder for the purpose of replacing broken glass o his greenhouse roof will welcome this 'chicken ladder.' The ladder rests across 2 glazing bai (2) on horizontal strips (3) and is securely hooked over the ridge of the house (4). It may t pushed easily along the ridge when change of position is required. The steps of the ladder ( = are nailed to the redwood slab (6). The ventilator (7) is shown closed, and at (7a) is show open under the ladder.

IX i. Odontonia Cardinalis, F.C.C.R.H.S. (Miltonia Lyceana F.C.C. x Odontoglossmn Purple Queen) (L. F. Hawkinson; courtesy Orchid Digest)

IX 2. Cymbidium Swallow Perfection (C. Alexander! Westonbirt var, x C. Pauwclsii var. Comte de Hemptinnc) (Alex D. Hawkcs)

X i. Cypripediiim Loin's Crampron X 2.    Cypripedium    Cheddington    (C. Wilson; courtesy Orchid Digest)

XI Potting Cattleyas (O. O. Meek; coi tesy Orchid Digest)

1. Plant in need of repotting. Notice t roots breaking from front lead—ideal tii to repot.
2. The plant is taken from the pot, ai the decayed material removed. The bac bulbs, which have no roots, may be c from the plant and started in gravel, the dormant eye may break and produ a new plant.
3. Well-potted plant with old bulbs clc to edge of pot, fore-bulb leaving room f new growth. Rhizome lies flat across pting medium.
4. Incorrectly potted  plant  growing u ward from potting medium and over ed; of pot.

XII 1. From flask seedlings ti blooming plant (Jack Wood) XII 3. Cattley; Mossiae x Laelio cattleya Rabeian; (Jack'Wood)

XII 2. Seedlings (Jack Wood) XII 4. Potinara Ruby—Stuart Low, 1934 (Charles O. Dunne; courtesy Orchid Digest)

XIII From seed to embryo (M. A. Bunow; courtesy Orchid Digest)

1. Seed as from pod, showing fertile and infertile seed
2. Seed 8 days after planting, showing beginning tubercles but no enlargement
3. Seed 8 days after planting, showing enlargement but no tubercles
4. Seed at 10 days
5. Seed at 11 days
6. Seed at 12 days, tubercles showing at side
7. Seed  at   14 days,  showing embryo breaking through capsule and  flattened area from which first leaf will appear
8. Seed at 16 days. Embryo free from capsule
9. Typical embryo at 18 days, free from capsule

XIV Brassocattleya H. G. Alexander (Cattleya citrina x Brassavola Digbyana) (Robert Johnson)

XV Brassocattleya Ilartland (L. F. Hawkmson; courtesy Orchid Digest)

XVI   1.  Laeliocattleya  Elissa  (Harold Johnson) XVI 2. Laelitleocatya Dulzura (Ruth M. Todd)

The simplest heating systems can be considered only expedi­ents—some of them dangerous ones. The fumes of a kerosene stove are disagreeable to humans but a few orchids in a tiny house will not find them so. The kerosene stove is excellent in of the night to refill the stove against the cold. A type of gas floor furnace, well vented and with the flame not directly open to the house, has been found satisfactory for the small green­house. Humidity must be maintained to offset dryness. Open gas heaters are a menace in the greenhouse, for if the flame is acci­dentally put out the fumes will quickly kill the plants. Electric heaters are too drying and too concentrated for plants near by and do not provide enough warmth for plants some distance away.

More elaborate systems are required for a completely satisfac­tory solution of the heating problem. For areas where the tem­perature does not fall below zero, hot-water systems operated by thermostatically controlled gas are very satisfactory. Where severe winters prevail, hot-water or steam systems with coal or oil burners will be required. There are many types from which to choose, but only one can be examined here in any detail. The simple gravity system has been found very efficient for small greenhouses (nine by twelve feet to twelve by fifteen feet). The best pipe for this or any system is the one and a half or two-inch hot-dipped galvan­ized, rust-resistant type. Black pipe is a good conductor of heat but is more susceptible to rust from the constant damp. In the sketch (Plate vn) the gas enters through a valve (1) and goes to the solenoid valve (2) (controlled by the thermostat [11]). From there it goes to the copper coil side-arm heater (coils should be at least % inch), which is controlled by a pilot light. Water enters the heater through the shut-off valve (7), which is closed after the pipes are filled. A valve (6) is used to drain the system. The water passes through the coils and rises as it is heated to the highest point (A). As the water heats, it expands, forcing some up into the expansion tank (9), which is open to the air at 10. Gravity carries the water to B, a drop of one-half in three inches being allowed. From B the water falls to the pipe (D-D), which is level with the ground, causing equal amounts of water to flow to both points. Water then flows from D down both sides of the house and back to F under the same drop as it did from A to B.

From F there is another drop back to the heater and the process is repeated. A water outlet (8), outside the shut-off valve, is pro­vided for watering the house.

The 'closed' system is similar to the 'open' system outlined above, but has a reduction valve from the city system and should have a 'bleeder' so that the maximum water pressure in the pipe does not exceed 28 pounds pressure per square inch. The disad­vantage of this layout is that heat may be lost by backing up into the city system.

The side-arm heater system with two-inch pipe is only suited for a small house in a mild climate. For the larger house in a mild climate it may be operated by a boiler or Arcola type of heater. Where temperatures drop below zero the pipe should be four inches, and heat should be supplied by an oil or coal boiler. The gravity system is probably not practical for the larger house. In such circumstances a circulating pump can be used to force the water through the pipe. The pump must be kept in good condition, for, if it should freeze, water will not circulate and the boiler may explode. The chimney should be taller than the roof and designed to keep injurious fumes from the house. Many ama­teurs use the shed housing their heater as a potting shed. It is conveniently placed for this purpose and will be warm in winter.

These plans are not for the 'ideal' greenhouse, if there is any such thing. The ideal, of course, would be three greenhouses. The first would be for the cool-growing orchids like Cymbidiums, some Cypripediums, and Odontoglossums, and would be kept at a minimum winter temperature of 48 degrees F. at night. The second, which might be called the intermediate house, would be kept at 60 to 65 degrees, a temperature suitable for Cattleya and allied genera. The third, or hothouse proper, would have a mini­mum night winter temperature of from 68° to 700, making it suitable for Phalaenopsis, Vandas, Dendrobiums, and the mottled-leaf slippers like Cypripedium Maudiae.

Most amateurs, however, lack space and resources for three houses, and with ingenuity one house can be departmentalized. A section away from the source of heat and infrequently penetrated by the sun should be selected for the orchids preferring coolness. One bench might be left without piping for this pur­pose. Warmer-growing plants can be placed in the warmest part of the greenhouse. Plants requiring direct sun, like Laelias and Cattleya gigas, can be placed right up against the glass. Whatever form of shading is used may be varied from one part of the roof to another to provide special conditions. Plants will have to be moved about the house until observation shows the spot in which a particular species will thrive best.

The framework and slats for the greenhouse illustrated in Plate VII were made of dry redwood. It is essential to use dry lumber for the slats or there will be considerable warping. The center ridge and side members were made of 2 x 3's and attached to the greenhouse with pipe flanges and nipples. Seven-inch nip­ples were used for the center ridge and 6-inch for the sides; the finished framework is then equidistant from the glass. Small wood wedges were placed on each side of the flanges on the ridge, so that the flange is on a flat surface. Cross pieces, from the center ridge to the side members, were 1 x 2's, nailed level to the side members and to the bottom of the center ridge. This permits putting small pieces of wood or strap iron at the top of the center ridge to hold the sections of slats down.

Each section of slats, consisting of battens (slats) 1/4 x 11/8 spaced 1 inch apart, is 6 feet wide and extends from the ridge to just below the eave on the greenhouse. Battens are nailed to 1 x 2's and held to the side members with bolts and thumb nuts. The greenhouse in the illustration runs north and south, and it was necessary to put a small framework of battens on the south of the house in the space between the main framework and the greenhouse (shown in photograph). If the greenhouse faced east-west, the battens would run up and down rather than lengthwise. The entire wood structure may be oiled with linseed oil or painted.

The following material is required for a 9x12 greenhouse with a 30 degree roof:
3—2 x 3 x 12 feet    9—3/4-inch pipe flanges
8—1 x 2 x 6 feet      3—3/4 x 7-inch pipe nipples
10—1 x 2 x 5 1/2 feet          6—3/4 x 6-inch pipe nipples
130—1/4 x 1 1/8 x6 feet          galvanized nails and screws

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