The Amateur's Greenhouse and Conservatory/Chapter 3
CHAPTER III.
examples of plant house construction and heating.
A few examples of the various forms and arrangements of greenhouses may prove of more service to many readers of this book than the foregoing enumerations of elementary principles. We shall begin with a very servicable span-roofed house, adapted for a mixed collection of plants, with pits adjoining on each side for bedders and frame plants. It is designed with a view to secure the utmost economy consistent with efficiency. It will be observed that the pitch of the roof is low, the ridge being only nine feet from the ground line. The width is twelve feet. In arranging the plants the tallest specimens are
SPAN-ROOF HOUSE WITH PITS FOR BEDDING PLANTS.
placed upon the centre stage, the next size on the side tables, and the smallest stuff in the pits on each side. By this arrangement everything will have ample head room, and at the same time be near the glass; moreover, they will be placed under the conditions most favorable for a frequent examination. If preferred, the walk may be made down the centre, with broad flat stages on each side. The house should be heated with a flow-and-return four-inch pipe on each side, and openings in each wall must be provided to allow the heat to escape into the pits to keep the inmates safe. There is no objection to the pits being heated with a separate system of pipes, from the same boiler, of course. Two-inch pipes will be large enough for the pits; and one passing down one pit and up the other will be quite sufficient for ordinary purposes, especially as the lights can be covered with mats in severe weather. The greenhouse floor should be laid with white and black tiles, unless stone can be procured at a cheap rate; but for the floor of the pits a bed of ashes will suffice. The openings in the wall should be provided with shutters, in case the frames should be occupied with hardy plants, that merely require protection from too much moisture; if side-lights are adopted, they should be made to slide, instead of pushing out, and, of course, be made to slide from the inside.
The next example is an improvement on the foregoing. The pits are removed, the space is wider, and the angle at ridge more sharp, and more ample staging is provided, the centre stage having the advantage of a course of pipes on each side, connected with the flow near the boiler. The width is seventeen feet, the height to the ridge nine feet. This would make a good vinery, and a number of plants could be grown beneath the vines, though, to be sure, some caution would be required in selecting them, and it would not be prudent to clothe the roof densely with the ample foliage of the vines.
SECTION OF SPAN-ROOF GREENHOUSE WITH STAGING AND HOT WATER PIPES.
Now, we propose to go to work and build a cheap span-roof house of a substantial nature, well adapted both for keeping a stock of bedding plants in winter and a fair supply of plants in flower all the year through. We must have a good wall to begin with, and reckon that as costing nothing in connection with the undertaking. We must next resolve to have a fixed roof, in order to use light rafters and secure ventilation at the back and front. One considerable item in the cost of glass-houses is the framing of sashes and the making them to slide open for airing. These not only consume a quantity of timber and increase the weight of the roof, which, in its turn, must be supported by large rafters, but they require the time and skill of a competent joiner to frame them. Now, so long as a roof is fixed firmly and steadily in its position, and without movable lights, large rafters may safely be dispensed with, and bars alone be used, as shown in the accompanying plans, the bars to vary in depth and thickness according to the width and
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SECTION OF LEAN-TO GREENHOUSE |
SECTION OF SASH-BAR. |
GROUND PLAN OF LEAN-TO GREENHOUSE.
the foot. These bars may be had ready grooved and planed at any of the steam saw and planing mills, and the purling, posts, wall-plate, boards to fix over the ventilators, &c., may also be bought ready for use, so that any ordinary carpenter or clever labourer may build such a house, and if a corner by the garden-wall can be spared it may be done for a small sum.
a, the back and end walls; b, openings in back and front walls for ventilation. Of these there should be plenty; a board hung by common joints, to cover them when not required open, may have a string and pulley attached for lifting, and its own weight will keep it down. c, raised platform of earth covered with slates, bedded in mortar to set plants upon. d, posts or columns to support purling (i), on which brackets are fixed to lay a shelf upon. e, path. f, stage. g, nine-inch earthen pipes, fitting well into each other, and the joints well secured, inside and out, with mortar, leading from furnace (o) to chimney (l), for the purpose of keeping out frost. h, stoke-hole sunk three feet, and covered with wood covers. The scale applies to the ground plan, to show its measurements.
LEAN-TO WITH DOUBLE-BOARDED BACK WALL.
Another serviceable lean-to is represented in the two figures that follow. This was designed to fill up a space at the end of a garden where there stood for a back wall a thin boarded fence. To strengthen this another wall was built of old floor boards, "tongued" together with hoop-iron, and placed two inches distant from the original wall, with a few stout upright posts to keep all firm. The space between the two walls was filled in with sawdust, and the result was a wall of a most substantial character. A very low roof, with ventilators opening at top, was adapted with brickwork front and sides, and wooden ventilators the whole length of the front. As an excavation in clay was made for this house, a bank of the original clay was left in front, and on this mounds were made for melons in summer, and—the house facing due south—fine crops were obtained. This, indeed, was one of the roughest and most useful houses we ever had, for many stove-plants throve in it, owing to its retention of sun-heat and its damp situation. In autumn a wooden trellis was laid over the bed
INTERIOR OF LEAN-TO HEATED BY MUSGRAVE’S SLOW COMBUSTION STOVE.
in front, and on this bedding plants were closely packed, and generally got through the winter well with the aid of a Musgrave’s stove that cost £6, and was fitted with a flue consisting of four-inch glazed drain-pipes. The bare space on the back wall, seen in the view of the interior, was occupied during winter with tall geraniums, that were kept for making pyramids in the flower-garden during the summer. The reason for the adoption of the Musgrave stove was, that it was impossible to obtain sufficient depth to make a proper stoke-hole for a furnace, owing to the water in the soil, and the reason the house was built at so low a level was, that it should not be seen above the line of the fence, as that would have spoiled a pretty view. Thus it is that extreme cases occur, and have to be met as best they may.
A nearly similar case occurred with a couple of houses which were so near the winter water level that it was a difficult matter to go deep enough for the furnace. This case affords an example of heating on the level, and must be described with some detail. The houses to be heated are a lean-to and a Paxtonian; they are so nearly on a level that a quick circulation is not to be hoped for, and the lean-to has beside it a well, which frequently overflows in the winter season. Between the highest point the water reaches and the flow-pipe in the lower house the perpendicular difference is thirty inches, and between the bottom of the boiler and the level of the water the difference is only fifteen inches.
If you want the quickest possible circulation of hot water, fit a perpendicular syphon through a saucepan lid, seal the lid down waterproof and fireproof, insert a small tube at the top of the syphon, and through that tube fill the whole concern with water, and then put the saucepan on the fire. The circulation will begin instanter, and will be perfect from the first moment that accessions of heat are communicated from the fire to the water. The laws which regulate the movements of heated fluids are fully explained and illustrated in the books that treat of physics and natural philosophy, so it is not worth while to go into that part of that subject here. It only concerns us to know that in a perpendicular column of water the movements caused by heat are most decisive and complete, and that every deviation from the perpendicular tends to arrest the motion, so that when we reach the horizontal, the rate of motion is reduced to a minimum, or may absolutely cease altogether, which in a certain sense is less than a minimum, as nothing is less than the least. In the heating of these two houses we had to calculate to a great nicety how to make the most of the perpendicular space at command—to consider, in fact, how much could be done between the lowest point at which the pipes could be placed in the houses, and the highest level of the water in the well. The lower house was the only difficulty; the other was so far above it that if we ever got a fire to burn, and water to get hot thereby, on a level sufficiently low to heat the lower house, the Paxtonian would be safe enough.
Now, it is worthy of observation that the plan adopted in this case was not the only one at our command. We might have taken round the houses a flow-pipe of very small bore and a return-pipe of very large bore, and by this means have secured a circulation, and derived our heat from the 
EXAMPLE OF HEATING ON THE LEVEL.
return-pipe chiefly. We preferred to heat the houses in the orthodox fashion, and selected for the purpose one of the upright conical boilers of the Thames Bank Company, and left Mr. Dunbar to fight it out, and the result of his operations was that the lower house was heated with four-inch flow-and-return placed side by side in the front of the house, on a dead level, and from these heat enough was derived to keep all safe in severe frosty weather.
The figure will show that the Paxtonian stands slightly above the level of the lean-to; so we had but to make sure of a fire in the furnace, and the heating of this house was an easy matter. The pipes had, however, to be taken a distance of twenty-five feet from the furnace to the Paxtonian; and, as this would cause a great waste of heat, a long, trough-like wooden box was fitted to the dwarf wall on which the pipes rested, and they were thus enclosed from the weather. The box was covered with stout shutters clothed with felt, and it became immediately a dark forcing pit, and has been used ever since, during the winter and early spring, for forcing sea-kale, asparagus, rhubarb, &c. The pipes in this box are of two inches bore, to cause a quick flow, and make the waste of heat the least possible; but, as soon as they enter the house, they are enlarged to four inches, and thus they pass all round the house, close under the glass, and resting on the borders. The arrangement may be understood from the subjoined diagram.
ARRANGEMENT OF PIPES IN EXAMPLE OF HEATING ON THE LEVEL.
A. Entrance to lean-to. B. Entrance to Paxtonian. C. Boiler.
D. Flow. E. E. Return. F. Forcing-pit.
The solution of a difficulty in this simple way is a matter of more than passing interest, for where it appeared impossible to employ a hot-water system it has been effectually accomplished, and a most excellent forcing-pit obtained into the bargain. It is an important exemplification of established principles that the lean-to which adjoins the boiler, and receives its pipes directly from it, obtains far less heat than the Paxtonian, which is twenty-five feet distant, and the pipes which supply it first have to heat a large body of air and material in the forcing-pit. The lean-to is never more than a decidedly cool greenhouse, but the Paxtonian may be heated to the pitch of a stove by simply driving the fire a little. The difference is due entirely to the fact, that from the boiler to the Paxtonian the pipes rise, whereas in the other house they are on a dead level throughout. This very fact proves that our difficulty in the first instance was not imaginary, and renders its solution the more satisfactory.
PAXTONIAN PLANT-HOUSE.
By this time some prudent reader will be asking if the question of “tenant right” in plant-houses is likely to engage our attention? Well, that is the very question we intend to illustrate in the next examples. The prudent reader need not, of course, be informed that, according to the law of the land, plant-houses, from the moment of their fixture in the soil, become the property of the freeholder. But it may be less generally known that the best house ever built is scarcely worth the trouble of removal after a few years have elapsed,
PORTABLE GREENHOUSE.
There are several kinds of portable houses now provided by enterprising manufacturers, and amongst many good ones that known as the “Paxtonian,” the invention of Sir Joseph Paxton, is, perhaps, the best. Leaving the reader to select for himself the ready-made article, we proceed to show how portable houses may be constructed by village carpenters and handy amateurs.
The house represented pp. 45, 46, 47 was built by Messrs. Walker & Co., Newcastle-on-Tyne, for our correspondent, Mr. Lant, of Cottonstone, Barnard Castle. The ground plan and section will explain the whole construction. The house is twelve feet long and eight feet wide; the side lights five feet high from
GROUND PLAN OF PORTABLE GEEENHOUSE.
the base; the roof ridge eight feet from the floor. There is an open space of two inches width for ventilation along the top line of the side lights, concealed by the zinc spouting, and another similar space along the ridge. Both these can be opened and closed at pleasure. The door panels and glass over door are on hinges, so as also to serve for ventilation. The interior is fitted with shelves two and a half feet wide. The house is heated from a boiler, which only holds a gallon of water, placed a foot deep below the surface of the soil. The hot-water pipes are two inches in diameter. The flue is a four-inch galvanized iron pipe; the fuel used is coke broken small. The cost of the house and its fittings was £25. Mr. Lant says that he has tested its portability, for he once removed it on a railway truck a distance of sixty miles. “We put three spokes under the base of the house on each side six spokes in all, and two men at each spoke carried it to the railway truck, and thence to its new site, in perfect safety and without drawing a nail. The house and twelve dozen plants were carried in perfect safety a distance of sixty miles on the North-Eastern Railway for 25s.”
SECTION OF PORTABLE GREENHOUSE.
The last example will be an improvement on the foregoing, with every particular of construction from first to last. The details of construction are represented pp. 48, 49, 50, and 52.
The diagram of the elevation shows a detached building set upon a raised platform of earth, to give it a greater apparent elevation, with a gravel walk surrounding it, and two steps placed in the grass slope, by which to ascend the platform. The house is composed of parts that, when taken to pieces, may be easily packed up conveniently for carriage. They consist, first, of the ground sill, which may be of teak, if the expense is not an object., seven inches wide, by four inches in thickness,
REMOVEABLE GEEENHOUSE.
the four sides of which are held together at the angles by means of irons screwed on with square-headed screws (Fig. 9a). No pegs or nails are to be driven into any of the mortise tenons, but in every part use, in lieu thereof, either the screws Fig. 9a or Fig. 9b. The studs are mortised into the sill, and have a substance of four and a half inches by four inches; and these again are mortised into the rafter-plate (see section, Fig. 11). Between these studs (see section. Fig. 10) the sashes (b) are set up, and to keep them steadily in their places splines (e) are braded on to the studs. These sashes may be exactly like those used in house building, without, of course, the accompaniment of boxes and weights. Upon the front of the stud a half-circular moulding (c) may be braded to give a degree of lightness to the appearance. Also to the same end, as well as to throw off water, let the sill be bevelled at d. Above the sashes are to be hung on pivots smalllights for ventilation. These may be opened and kept so by means of a small iron having holes in it, to drop on to a pin fixed in the lower sash (Figs. 11—5). This iron must also have a joint so as to hang down when the ventilator is shut. The rafter plate and gutter are formed out of one piece, seven inches
GROUND PLAN OF REMOVABLE GREENHOUSE.
must have screws (Fig. 9b), commonly known as bed-screws, put through the top and bottom into the ridge-tree and rafter-plate. The rafters and studs must likewise be secured by these screws, as at Figs. 11—4. In the section, Figs. 1, 2, and 3, show the door stud, the angle stud, and one of the side studs, which are all of one size, the difference consisting only in the putting on of splines and mouldings. The end gable lights may be fixed in their places by means of splines, in the same manner as the side sashes. In the same section, Fig. 8 represents light iron rods suspended from the rafters, as bearers of light shelves, for the accommodation of bedding plants, or other small things which require a situation near the glass. Referring to the ground plan (9, 9, 9, 9) are boxes placed in the angles, in which may be planted climbers, to train over the roof or sides of the building. Fig. 7, stage, which must be strong enough to bear the plants, but may be made in parts, so that it can be removed without having to be knocked to pieces. It will be necessary, in order to protect the building from damp and the liability to settle down, to place it upon some firm and solid matter let into the ground, as brick piers or wood blocks. A platform of bricks laid on the surface, gives a firm and lasting foundation, provided the subsoil has not been recently disturbed.
The heating of a moveable house must also be managed by a moveable apparatus, which will be some kind of stove, and which must have a pan on the top to hold water; and as artificial heat in such a house as this will only be required in winter, the stove might, for that period, occupy a place near one of the doors, and the smoke-tube be carried through the glass at the top of the house. Should a building of this kind be required for vines, the side lights should be reduced to one half the height, and these to open, as here shown, for ventilation; the roof lights would then be longer, and a much steeper roof obtained. A small aperture or two at the ridge, capable of being closed by a wood slide, would, with the side lights hung as recommended, effect a perfect ventilation. The walk would, in such a house, be down the centre, and the vines might be planted in boxes, having large openings in their bottoms to allow the roots to escape into a border made up inside the house for that purpose. The planting them in boxes would enable them to bear removal at almost any season.
SECTION VIEW OF REMOVABLE GREENHOUSE.
Between the conservatory and the greenhouse there is about the same difference as between a dinner and a luncheon. It is impossible to draw a hard-and-fast line between them, and yet they differ in plan and purpose very decidedly, The greenhouse is intended principally for production, and is more or less of a storehouse. The conservatory is intended for enjoyment and display. Some very humble and, in some cases, useless glass structures are styled “conservatories,” but the term applies properly to an edifice of sufficient size to accommodate camellias and orange trees, and the free movement of full-grown persons attired in a manner which would render it inconvenient for them to come in contact with damp flower-pots. A conservatory should be more or less of a garden under glass, and adapted for frequent resort and agreeable assemblage at all seasons, and especially at times of festivity. Hence, in designing a structure of this class, we must not adhere strictly to the advice given in the first chapter of this work, but endeavour to combine elegance, head room, and airiness, with conditions suitable for plant life. It must be confessed that the low roofs, which suit the majority of plants so well, are undignified, and therefore we must abandon that rule in the case of a conservatory. But in doing so, it will be well to bear in mind that not one of our plants will alter its nature to suit our fancies and fashions, and therefore there must be a limit to every extension of the primitive idea of a plant-house, for above all things we are bound to secure for the vegetation the house is to shelter conditions favorable to its prosperity. Now, the apparent difficulty may be disposed of by remembering that abundance of light and a constantly moving atmosphere are the two chief requisites to be provided for in the construction of a plant-house, no matter whether we call it a stove, a greenhouse, or a conservatory. Darkness, stagnant air, and keen draughts, are the principal enemies of plants that are shut up in houses, and it is compatible with the highest elegance of design, and the most artistic finish of detail, to ensure the best possible protection for them against these destructive agencies. As we must have aerial as well as lateral space in a conservatory, so, to make the contents worthy of the edifice, we must employ plants of large growth, and a certain number of them should aspire towards the roof, to carry the eye upward and fill the space above that would, if unoccupied, make an unpleasant impression, however richly
CONSERVATORY BY BOULTON AND CO., NORWICH.
CONSERVATORY PLANT-STAGE BY BOULTON AND CO., NORWICH.
the stages and tables might be furnished. Happily, we are rich in noble plants adapted for the purpose, and that require for their preservation a winter temperature which exactly suits the human constitution, so that, by prudent selection and good management, a conservatory may be made a place of agreeable resort at every season of the year, and be especially pleasant to afford a change of scene and occupation in the winter season. It is, however, painfully common to meet with grand conservatories that are utterly unfit for their intended purpose, the work of architects and builders who were so unfortunate as to know nothing of plant growing. When we are approaching a conservatory with a bold frontage of stone pilasters and heavy cornice and recessed windows, in the style of a Grecian temple, we are fully advertised of the appearance the plants will present when we gain access to the interior. The conservatories that architects unskilled in horticulture provide for their employers usually have this distinguishing character, that no plant will thrive in them, and very few will live in them; therefore, as conservatories are costly things, it will be well for those who intend to pay for them, to take measures, in good time, to secure suitable designs, and employ competent persons to carry them into effect.
