This section is from the book "The Gardener V3", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
In the early part of January last we had an opportunity of inspecting a new Orchid-house that Mr William Bull, of the King's Road, Chelsea, S.W., has just erected for the growth of Orchids. "This house has been constructed so as to embody many of the special features that have from time to time been suggested and described as to the manner in which an Orchid-house should be erected. In its present form it seems to be a model Orchid-house for amateur growers, and seems likely to prove an admirable house of its kind for nurserymen also. It is a span-roofed structure, 45 feet long, 15 feet 6 inches wide, and 9 feet high in the centre. The outer walls are 2 feet 6 inches high, and on this wall there is a 2-feet glazed frame on which the roof rests. Along the apex of the roof there is a good substantial wooden coping, under which a roller is fixed, which, when suitable materials for shading are fastened to it, will be used either for keeping out the bright rays of the sun in summer, or for keeping out frost in severe weather in winter. The house is divided into four compartments.
The first is a lobby (5 feet by 4), which must be entered before reaching the other divisions; so that, let the condition of the external atmosphere be what it may, no cold draughts are admitted into the Orchid-house proper. The first division, after passing through the lobby, is 11 feet in length, and is intended for cool Orchids and flowering specimens. This is no doubt a great point in connection with Orchid culture, as not only do the flowers last much longer in such a structure, but their beauty is seen to greater advantage and much more pleasure by ladies than when the plants are regularly kept in the hot and damp atmosphere of the growing-house. The second division, which is called the East Indian House, is 19 feet 6 inches in length, and the third, or Cattleya House, is 20 feet long. Down the centre of the two latter compartments is an open tank, containing three hot-water pipes for giving off moisture. The tanks are kept filled by a pipe and taps from the reservoir outside. These pipes are also perfectly under control, as, by using valves placed in the cool-house, the temperature can be raised or lowered as required. At the end of the Cattleya House a compact and useful potting-shed, heated by hot water, is attached.
This being entered from the house, greatly facilitates the operation of potting, etc. And here, again, is a precaution against draught. Under the floor of this shed is a spacious tank, which receives all the rain-water from the roof. Pipes are laid from the hot-water tank in the house to this cistern, so that warm or chilled water can be easily had when required, either for watering the plants or for any other purpose. The hot-water pipes for heating the houses are arranged along the outer walls, and provision is made for regulating the temperature in each house, by having separate stop-valves fitted to each set of piping. Ventilation has also been provided with the same care to prevent the introduction of cold currents of air. This is effected by having small apertures made in the outer wall, just below the heating medium, so that cold air, before passing into the interior, must first come in contact with the hot pipes, and so become somewhat warmed. The ventilation is effected simply by a sufficient number of small sliding glass-frames for the requirements of each house.
Another important feature is the staging, which is open, both in the breadth that runs down the centre over the tanks and around the sides; the latter also, instead of being fixed close up to the wall, have a space of about 6 inches between them, for the heat to pass into that portion of the house which in most other erections is the coldest part - i.e., that portion of the stage nearest the glass. The stages being made open, the genial humidity which rises from the tanks is allowed to pass freely amongst the plants throughout the house, and the paths can be kept comparatively dry, which is a pleasure scarcely dreamt of where no tanks of this kind are provided".
For this capital description of the details of Mr Bull's Orchid-house we are indebted to the 'Gardeners' Chronicle;' but since this report was taken, Mr Bull has added one other improvement of considerable merit. Finding that the moist atmosphere became condensed on the glass and rafters forming the roof, and then fell off in heavy drops, to the manifest injury of some of the plants, especially of those in flower, zinc gutters have been attached to each rafter throughout the house. The moisture on the glass invariably runs to one side or the other, and, falling from the rafter into the gutter, is by means of pipes carried down behind the side-stages into the tanks beneath the houses. Mr Bull deserves much credit for the admirable manner in which all the details of this excellently-constructed house have been arranged.
At the time of our visit the first division of the house was very gay with blooming Orchids. It was a bitter cold day when we went to Chelsea, a biting northeast wind prevailing; and yet, owing to the precaution of this lobby, but little of this found its way into the house as we entered it. Some lovely forms of Lycaste Skinneri first claimed attention. These admit of great variation, and some are very beautiful indeed: one named Marginata had a very rich lip, margined with white. There could also be observed a tendency to flower in pairs; in several instances twin-blooms were produced on one stem. L. Barringtonia, var. grandi-flora, was also very fine, and was figured by Dr Hooker in his 'Botanical Magazine ' in 1867. A plant of Sophronitis grandiflora had six charming flowers finely coloured and fully expanded, with three buds yet to open. Some plants of Laelia anceps were very showy, the flowers borne on long stems, having terminal groups of two or three blossoms. One form had a fine dark lip, and darker sides to the throat than is usually seen, and a good blotch of yellow in the lip. This is to be called L. anceps flavida. Many plants of L. anceps were just coming into bloom. A little later in blooming is L. furfuracea, the buds of which were just on the point of opening.