Chapter III: Part II: The Practice of Horticulture (1)

The details of horticultural practice naturally range under the three heads of flowers, fruits and vegetables (see also FRUIT AND FLOWER FARMING). There are, however, certain general aspects of the subject which will be more conveniently noticed apart, since they apply alike to each department. We shall therefore first treat of these under four headings: formation and preparation of the garden, garden structures and edifices, garden materials and appliances, and garden operations.

I. _Formation and Preparation of the Garden._

_Site._--The site chosen for the mansion will more or less determine that of the garden, the pleasure grounds and flower garden being placed so as to surround or lie contiguous to it, while the fruit and vegetable gardens, either together or separate, should be placed on one side or in the rear, according to fitness as regards the nature of the soil and subsoil, the slope of the surface or the general features of the park scenery. In the case of villa gardens there is usually little choice: the land to be occupied is cut up into plots, usually rectangular, and of greater or less breadth, and in laying out these plots there is generally a smaller space left in the front of the villa residence and a larger one behind, the front plot being usually devoted to approaches, shrubbery and plantations, flower beds being added if space permits, while the back or more private plot has a piece of lawn grass with flower beds next the house, and a space for vegetables and fruit trees at the far end, this latter being shut off from the lawn by an intervening screen of evergreens or other plants. Between these two classes of gardens there are many gradations, but our remarks will chiefly apply to those of larger extent.

The almost universal practice is to have the fruit and vegetable gardens combined; and the flower garden may sometimes be conveniently placed in juxtaposition with them. When the fruit and vegetable gardens are combined, the smaller and choicer fruit trees only should be admitted, such larger-growing hardy fruits as apples, pears, plums, cherries, &c., being relegated to the orchard.

Ground possessing a gentle inclination towards the south is desirable for a garden. On such a slope effectual draining is easily accomplished, and the greatest possible benefit is derived from the sun's rays. It is well also to have an open exposure towards the east and west, so that the garden may enjoy the full benefit of the morning and evening sun, especially the latter; but shelter is desirable on the north and north-east, or in any direction in which the particular locality may happen to be exposed. In some places the south-western gales are so severe that a belt of trees is useful as a break wind and shelter.

_Soil and Subsoil._--A hazel-coloured loam, moderately light in texture, is well adapted for most garden crops, whether of fruits or vegetables, especially a good warm deep loam resting upon chalk; and if such a soil occurs naturally in the selected site, but little will be required in the way of preparation. If the soil is not moderately good and of fair depth, it is not so favourable for gardening purposes. Wherever the soil is not quite suitable, but is capable of being made so, it is best to remedy the defect at the outset by trenching it all over to a depth of 2 or 3 ft., incorporating plenty of manure with it. A heavy soil, although at first requiring more labour, generally gives far better results when worked than a light soil. The latter is not sufficiently retentive of moisture and gets too hot in summer and requires large quantities of organic manures to keep it in good condition. It is advantageous to possess a variety of soils; and if the garden be on a slope it will often be practicable to render the upper part light and dry, while the lower remains of a heavier and damper nature.

Natural soils consist of substances derived from the decomposition of various kinds of rocks, the bulk consisting of clay, silica and lime, in various proportions. As regards preparation, draining is of course of the utmost importance. The ground should also be trenched to the depth of 3 ft. at least, and the deeper the better so as to bring up the subsoil--whether it be clay, sand, gravel, marl, &c.--for exposure to the weather and thus convert it from a sterile mass into a living soil teeming with bacteria. In this operation all stones larger than a man's fist must be taken out, and all roots of trees and of perennial weeds carefully cleared away. When the whole ground has been thus treated, a moderate liming will, in general, be useful, especially on heavy clay soils. After this, supposing the work to have occupied most of the summer, the whole may be laid up in ridges, to expose as great a surface as possible to the action of the winter's frost.

Argillaceous or clay soils are those which contain a large percentage
(45-50) of clay, and a small percentage (5 or less) of lime. These are
unfitted for garden purposes until improved by draining, liming,
trenching and the addition of porous materials, such as ashes, burnt
ballast or sand, but when thoroughly improved they are very fertile
and less liable to become exhausted than most other soils. Loamy soils
contain a considerable quantity (30-45%) of clay, and smaller
quantities of lime, humus and sand. Such soils properly drained and
prepared are very suitable for orchards, and when the proportion of
clay is smaller (20-30%) they form excellent garden soils, in which
the better sort of fruit trees luxuriate. Marly soils are those which
contain a considerable percentage (10-20) of lime, and are called clay
marls, loamy marls and sandy marls, according as these several
ingredients preponderate. The clay marls are, like clay soils, too
stiff for garden purposes until well worked and heavily manured; but
loamy marls are fertile and well suited to fruit trees, and sandy
marls are adapted for producing early crops. Calcareous soils, which
may also be heavy, intermediate or light, are those which contain more
than 20% of lime, their fertility depending on the proportions of clay
and sand which enter into their composition; they are generally cold
and wet. Vegetable soils or moulds, or humus soils, contain a
considerable percentage (more than 5) of humus, and embrace both the
rich productive garden moulds and those known as peaty soils.

The nature of the subsoil is of scarcely less importance than that of the surface soil. Many gardeners are still afraid to disturb an unsuitable subsoil, but experienced growers have proved that by bringing it up to the surface and placing plenty of manure in the bottoms of the various trenches, the very best results are attained in the course of a season or so. An uneven subsoil, especially if retentive, is most undesirable, as water is apt to collect in the hollows, and thus affect the upper soil. The remedy is to make the plane of its surface agree with that of the ground. When there is a hard pan this should be broken up with the spade or the fork, and have plenty of manure mixed with it. When there is an injurious preponderance of metallic oxides or other deleterious substances, the roots of trees would be affected by them, and they must therefore be removed. When the subsoil is too compact to be pervious to water, effectual drainage must be resorted to; when it is very loose, so that it drains away the fertile ingredients of the soil as well as those which are artificially supplied, the compactness of the stratum should be increased by the addition of clay, marl or loam. The best of all subsoils is a dry bed of clay overlying sandstone.

_Plan._--In laying out the garden, the plan should be prepared in minute detail before commencing operations. The form of the kitchen and fruit garden should be square or oblong, rather than curvilinear, since the working and cropping of the ground can thus be more easily carried out. The whole should be compactly arranged, so as to facilitate working, and to afford convenient access for the carting of the heavy materials. This access is especially desirable as regards the store-yards and framing ground, where fermenting manures and tree leaves for making up hot beds, coals or wood for fuel and ingredients for composts, together with flower-pots and the many necessaries of garden culture, have to be accommodated. In the case of villas or picturesque residences, gardens of irregular form may be permitted; when adapted to the conditions of the locality, they associate better with surrounding objects, but in such gardens wall space is usually limited.

The distribution of paths must be governed by circumstances. Generally speaking, the main paths for cartage should be 8 ft. wide, made up of 9 in. hard core covered by 4 in. of gravel or ash, with a gentle rise to centre to throw off surface water. The smaller paths, not intended for cartage, should be 4 ft. to 6 ft. wide, according to circumstances, made up of 6 in. hard core and 3 in. of gravel or ash, and should be slightly raised at centre.

A considerable portion of the north wall is usually covered in front with the glazed structures called forcing-houses, and to these the houses for ornamental plants are sometimes attached; but a more appropriate site for the latter is the flower garden, when that forms a separate department. It is well, however, that everything connected with the forcing of fruits or flowers should be concentrated in one place. The frame ground, including melon and pine pits, should occupy some well-sheltered spot in the slips, or on one side of the garden, and adjoining to this may be found a suitable site for the compost ground, in which the various kinds of soils are kept in store, and in which also composts may be prepared.

As walls afford valuable space for the growth of the choicer kinds of hardy fruits, the direction in which they are built is of considerable importance. In the warmer parts of the country the wall on the north side of the garden should be so placed as to face the sun at about an hour before noon, or a little to the east of south; in less favoured localities it should be made to face direct south, and in still more unfavourable districts it should face the sun an hour after noon, or a little west of south. The east and west walls should run parallel to each other, and at right angles to that on the north side, in all the most favoured localities; but in colder or later ones, though parallel, they should be so far removed from a right angle as to get the sun by eleven o'clock. On the whole, the form of a parallelogram with its longest sides in the proportion of about five to three of the shorter, and running east and west, may be considered the best form, since it affords a greater extent of south wall than any other.

Fig. 1 represents a garden of one acre and admits of nearly double the
number of trees on the south aspect as compared with the east and
west; it allows a greater number of espalier or pyramid trees to face
the south; and it admits of being divided into equal principal
compartments, each of which forms nearly a square. The size of course
can be increased to any requisite extent. That of the royal gardens at
Frogmore, 760 ft. from east to west and 440 ft. from north to south,
is nearly of the same proportions.

The spaces between the walls and the outer fence are called "slips." A considerable extent is sometimes thus enclosed, and utilized for the growth of such vegetables as potatoes, winter greens and sea-kale, for the small bush fruits, and for strawberries. The slips are also convenient as affording a variety of aspects, and thus helping to prolong the season of particular vegetable crops.

_Shelter._--A screen of some kind to temper the fury of the blast is absolutely necessary. If the situation is not naturally well sheltered, the defect may be remedied by masses of forest trees disposed at a considerable distance so as not to shade the walls or fruit trees. They should not be nearer than, say, 50 yds., and may vary from that to 100 or 150 yds. distance according to circumstances, regard being had especially to peculiarities occasioned by the configuration of the country, as for instance to aerial currents from adjacent eminences. Care should be taken, however, not to hem in the garden by crowded plantations, shelter from the prevailing strong winds being all that is required, while the more open it is in other directions the better. The trees employed for screens should include both those of deciduous and of evergreen habit, and should suit the peculiarities of local soil and climate. Of deciduous trees the sycamore, wych-elm, horse-chestnut, beech, lime, plane and poplar may be used,--the abele or white poplar, _Populus alba_, being one of the most rapid-growing of all trees, and, like other poplars, well suited for nursing other choicer subjects; while of evergreens, the holm oak, holly, laurel (both common and Portugal), and such conifers as the Scotch, Weymouth and Austrian pines, with spruce and silver firs and yews, are suitable. The conifers make the most effective screens.

Extensive gardens in exposed situations are often divided into compartments by hedges, so disposed as to break the force of high winds. Where these are required to be narrow as well as lofty, holly, yew or beech is to be preferred; but, if there is sufficient space, the beautiful laurel and the bay may be employed where they will thrive. Smaller hedges may be formed of evergreen privet or of tree-box. These subordinate divisions furnish, not only shelter but also shade, which, at certain seasons, is peculiarly valuable.

Belts of shrubbery may be placed round the slips outside the walls; and these may in many cases, or in certain parts, be of sufficient breadth to furnish pleasant retired promenades, at the same time that they serve to mask the formality of the walled gardens, and are made to harmonize with the picturesque scenery of the pleasure ground.

_Water Supply._--Although water is one of the most important elements in plant life, we do not find one garden in twenty where even ordinary precautions have been taken to secure a competent supply. Rain-water is the best, next to that river or pond water, and last of all that from springs; but a chemical analysis should be made of the last before introducing it, as some spring waters contain mineral ingredients injurious to vegetation. Iron pipes are the best conductors; they should lead to a capacious open reservoir placed outside the garden, and at the highest convenient level, in order to secure sufficient pressure for effective distribution, and so that the wall trees also may be effectually washed. Stand-pipes should be placed at intervals beside the walks and in other convenient places, from which water may at all times be drawn; and to which a garden hose can be attached, so as to permit of the whole garden being readily watered. The mains should be placed under the walks for safety, and also that they may be easily reached when repairs are required. Pipes should also be laid having a connexion with all the various greenhouses and forcing-houses, each of which should be provided with a cistern for aerating the daily supplies. In fact, every part of the garden, including the working sheds and offices, should have water supplied without stint.

_Fence._--Gardens of large extent should be encircled by an outer boundary, which is often formed by a sunk wall or ha-ha surrounded by an invisible wire fence to exclude ground game, or consists of a hedge with low wire fence on its inner side. Occasionally this sunk wall is placed on the exterior of the screen plantations, and walks lead through the trees, so that views are obtained of the adjacent country. Although the interior garden receives its form from the walls, the ring fence and plantations may be adapted to the shape and surface of the ground. In smaller country gardens the enclosure or outer fence is often a hedge, and there is possibly no space enclosed by walls, but some divisional wall having a suitable aspect is utilized for the growth of peaches, apricots, &c., and the hedge merely separates the garden from a paddock used for grazing. The still smaller gardens of villas are generally bounded by a wall or wood fence, the inner side of which is appropriated to fruit trees. For the latter walls are much more convenient and suitable than a boarded fence, but in general these are too low to be of much value as aids to cultivation, and they are best covered with bush fruits or with ornamental plants of limited growth.

_Walks._--The best material for the construction of garden walks is good binding gravel. The ground should be excavated to the depth of a foot or more--the bottom being made firm and slightly concave, so that it may slope to the centre, where a drain should be introduced; or the bottom may be made convex and the water allowed to drain away at the sides. The bottom 9 in. should be filled in compactly with hard, coarse materials, such as stones, brickbats, clinkers, burned clay, &c., on which should be laid 2 or 3 in. of coarse gravel, and then 1 or 2 in. of firm binding gravel on the surface. The surface of the walks should be kept well rolled, for nothing contributes more to their elegance and durability.

All the principal lines of walk should be broad enough to allow at least three persons to walk abreast; the others may be narrower, but a multitude of narrow walks has a puny effect. Much of the neatness of walks depends upon the material of which they are made. Gravel from an inland pit is to be preferred; though occasionally very excellent varieties are found upon the sea-coast. Gravel walks must be kept free from weeds, either by hand weeding, or by the use of one of the many weed killers now on the market. In some parts of the country the available material does not bind to form a close, even surface, and such walks are kept clean by hoeing.

Grass walks were common in English gardens during the prevalence of the Dutch taste, but, owing to the frequent humidity of the climate, they have in a great measure been discarded. Grass walks are made in the same way as grass lawns. When the space to be thus occupied is prepared, a thin layer of sand or poor earth is laid upon the surface and over this a similar layer of good soil. This arrangement is adopted in order to prevent excessive luxuriance in the grass. In many modern gardens pathways made of old paving stones lead from the house to different parts. They give an old-fashioned and restful appearance to a garden, and in the interstices charming little plants like thyme, _Ionopsidium acaule_, &c., are allowed to grow.

_Edgings._--Walks are separated from the adjoining beds and borders in a variety of ways. If a living edging is adopted, by far the best is afforded by the dwarf box planted closely in line. It is of extremely neat growth, and when annually clipped will remain in good order for many years. Very good edgings, but of a less durable character, are formed by thrift (_Armeria vulgaris_), double daisy (_Bellis perennis_), gentianella (_Gentiana acaulis_) and London pride (_Saxifraga umbrosa_), _Cerastium tomentosum_, _Stachys lavata_ and the beautiful evergreen _Veronica rupestris_ with sheets of bright blue flowers close to the ground, or by some of the finer grasses very carefully selected, such as the sheep's fescue (_Festuca ovina_) or its glaucous-leaved variety. Indeed, any low-growing herbaceous plant, susceptible of minute division, is suitable for an edging. Amongst shrubby plants suitable for edgings are the evergreen candytuft (_Iberis sempervirens_), _Euonymus radicans variegata_, ivy, and _Euonymus microphyllus_--a charming little evergreen with small serrated leaves. Edgings may also be formed of narrow slips of sandstone flag, slate, tiles or bricks. One advantage of using edgings of this kind, especially in kitchen gardens, is that they do not harbour slugs and similar vermin, which all live edgings do, and often to a serious extent, if they are left to grow large. In shrubberies and large flower-plots, verges of grass-turf, from 1 to 3 ft. in breadth, according to the size of the border and width of the walk, make a very handsome edging, but they should not be allowed to rise more than an inch and a half above the gravel, the grass being kept short by repeated mowings, and the edges kept trim and well-defined by frequently clipping with shears and cutting once or twice a year with an edging iron.

II. _Garden Structures._

_Walls._--The position to be given to the garden walls has been already referred to. The shelter afforded by a wall, and the increased temperature secured by its presence, are indispensable in the climate of Great Britain, for the production of all the finer kinds of outdoor fruits; and hence the inner side of a north wall, having a southern aspect, is appropriated to the more tender kinds. It is, indeed, estimated that such positions enjoy an increased temperature equal to 7 deg. of latitude--that is to say, the mean temperature within a few inches of the wall is equal to the mean temperature of the open plain 7 deg. farther south. The eastern and western aspects are set apart for fruits of a somewhat hardier character.

Where the inclination of the ground is considerable, and the presence of high walls would be objectionable, the latter may be replaced by sunk walls. These should not rise more than 3 ft. above the level of the ground behind them. As dryness is favourable to an increase of heat, such walls should be either built hollow or packed behind to the thickness of 3 or 4 ft. with rubble stones, flints, brickbats or similar material, thoroughly drained at bottom. For mere purposes of shelter a height of 6 or 7 ft. will generally be sufficient for the walls of a garden, but for the training of fruit trees it is found that an average height of 12 ft. is more suitable. In gardens of large size the northern or principal wall may be 14 ft., and the side walls 12 ft. in height; while smaller areas of an acre or so should have the principal walls 12 and the side walls 10 ft. in height. As brick is more easily built hollow than stone, it is to be preferred for garden walls. A 14-in. hollow wall will take in its construction 12,800 bricks, while a solid 9-in. one, with piers, will take 11,000; but the hollow wall, while thus only a little more costly, will be greatly superior, being drier and warmer, as well as more substantial. Bricks cannot be too well burnt for garden walls; the harder they are the less moisture will they absorb. Many excellent walls are built of stone. The best is dark-coloured whinstone, because it absorbs very little moisture, or in Scotland Caithness pavement 4 in. thick. The stones can be cut (in the quarries) to any required length, and built in regular courses. Stone walls should always be built with thin courses for convenience of training over their surface. Concrete walls, properly coped and provided with a trellis, may in some places be cheapest, and they are very durable. Common rubble walls are the worst of all.

The coping of garden walls is important, both for the preservation of the walls and for throwing the rain-water off their surfaces. It should not project less than from 2 to 2(1/2) in., but in wet districts may be extended to 6 in. Stone copings are best, but they are costly, and Portland cement is sometimes substituted. Temporary copings of wood, which may be fixed by means of permanent iron brackets just below the stone coping, are extremely useful in spring for the protection of the blossoms of fruit trees. They should be 9 in. or 1 ft. wide, and should be put on during spring before the blossom buds begin to expand; they should have attached to them scrim cloth (a sort of thin canvas), which admits light pretty freely, yet is sufficient to ward off ordinary frosts; this canvas is to be let down towards evening and drawn up again in the morning. These copings should be removed when they are of no further utility as protectors, so that the foliage may have the full benefit of rain and dew. Any contrivance that serves to interrupt radiation, though it may not keep the temperature much above freezing, will be found sufficient. Standard fruit trees must be left to take their chance; and, indeed from the lateness of their flowering, they are generally more injured by blight, and by drenching rains, which wash away the pollen of the flowers, than by the direct effects of cold.

_Espalier Rails._--Subsidiary to walls as a means of training fruit trees, espalier rails were formerly much employed, and are still used in many gardens. In their simplest form, they are merely a row of slender stakes of larch or other wood driven into the ground, and connected by a slight rod or fillet at top. The use of iron rails has now been almost wholly discontinued on account of metallic substances acting as powerful conductors of both heat and cold in equal extremes. Standards from which galvanized wire is tightly strained from one end to the other are preferable and very convenient. Trees trained to them are easily got at for all cultural operations, space is saved, and the fruit, while freely exposed to sun and air, is tolerably secure against wind. They form, moreover, neat enclosures for the vegetable quarters, and, provided excess of growth from the centre is successfully grappled with, they are productive in soils and situations which are suitable.

_Plant Houses._--These include all those structures which are more intimately associated with the growth of ornamental plants and flowers, and comprise conservatory, plant stove, greenhouse and the subsidiary pits and frames. They should be so erected as to present the smallest extent of opaque surface consistent with stability. With this object in view, the early improvers of hot-house architecture substituted metal for wood in the construction of the roofs, and for the most part dispensed with back walls; but the conducting power of the metal caused a great irregularity of temperature, which it was found difficult to control; and, notwithstanding the elegance of metallic houses, this circumstance, together with their greater cost, has induced most recent authorities to give the preference to wood. The combination of the two, however, shows clearly that, without much variation of heat or loss of light, any extent of space may be covered, and houses of any altitude constructed.

The earliest notice we have of such structures is given in the Latin
writers of the 1st century (Mart. _Epigr._ viii. 14 and 68); the
[Greek: Adonidos kepoi], to which allusion is made by various Greek
authors, have no claim to be mentioned in this connexion. Columella
(xi. 3, 51, 52) and Pliny (_H.N._ xix. 23) both refer to their use in
Italy for the cultivation of the rarer and more delicate sorts of
plants and trees. Seneca has given us a description of the application
of hot water for securing the necessary temperature. The botanist
Jungermann had plant houses at Altdorf in Switzerland; those of
Loader, a London merchant, and the conservatory in the Apothecaries'
Botanic Garden at Chelsea, were among the first structures of the kind
erected in British gardens. These were, however, ill adapted for the
growth of plants, as they consisted of little else than a huge chamber
of masonry, having large windows in front, with the roof invariably
opaque. The next step was taken when it became fashionable to have
conservatories attached to mansions, instead of having them in the
pleasure grounds. This arrangement brought them within the province of
architects, and for nearly a century utility and fitness for the
cultivation of plants were sacrificed, as still is often the case, to
the unity of architectural expression between the conservatory and the
mansion.

Plant houses must be as far as possible impervious to wet and cold air from the exterior, provision at the same time being made for ventilation, while the escape of warm air from the interior must also be under control. The most important part of the enclosing material is necessarily glass. But as the rays of light, even in passing through transparent glass, lose much of their energy, which is further weakened in proportion to the distance it has to travel, the nearer the plant can be placed to the glass the more perfectly will its functions be performed; hence the importance of constructing the roofs at such an angle as will admit the most light, especially sunlight, at the time it is most required. Plants in glass houses require for their fullest development more solar light probably than even our best hot-houses transmit--certainly much more than is transmitted through the roofs of houses as generally constructed.

Plant houses constructed of the best Baltic pine timber are very durable, but the whole of the parts should be kept as light as possible. In many houses, especially those where ornament is of no consequence, the rafters are now omitted, or only used at wide intervals, somewhat stouter sash-bars being adopted, and stout panes of glass (usually called 21-oz.) 12 to 18 in. wide, made use of. Such houses are very light; being also very close, they require careful ventilation. The glass roof is commonly designed so as to form a uniform plane or slope from back to front in lean-to houses (fig. 2), and from centre to sides in span-roofed houses. To secure the greatest possible influx of light, some horticulturists recommend curvilinear roofs; but the superiority of these is largely due to the absence of rafters, which may also be dispensed with in plain roofs. They are very expensive to build and maintain. Span and ridge-and-furrow roofs, the forms now mostly preferred, are exceedingly well adapted for the admission of light, especially when they are glazed to within a few inches of the ground. They can be made, too, to cover in any extent of area without sustaining walls. Indeed, it has been proposed to support such roofs to a great extent upon suspension principles, the internal columns of support being utilized for conducting the rain-water off the roof to underground drains or reservoirs. The lean-to is the least desirable form, since it scarcely admits of elegance of design, but it is necessarily adopted in many cases.

In glazing, the greater the surface of glass, and the less space occupied by rafters and astragals as well as overlaps, the greater the admission of light. Some prefer that the sash-bars should be grooved instead of rebated, and this plan exposes less putty to the action of the weather. The simple bedding of the glass, without the use of over putty, seems to be widely approved; but the glass may be fixed in a variety of other ways, some of which are patented.

The _Conservatory_ is often built in connexion with the mansion, so as
to be entered from the drawing-room or boudoir. But when so situated
it is apt to suffer from the shade of the building, and is
objectionable on account of admitting damp to the drawing-room. Where
circumstances will admit, it is better to place it at some distance
from the house, and to form a connexion by means of a glass corridor.
In order that the conservatory may be kept gay with flowers, there
should be a subsidiary structure to receive the plants as they go out
of bloom. The conservatory may also with great propriety be placed in
the flower garden, where it may occupy an elevated terrace, and form
the termination of one of the more important walks.

Great variety of design is admissible in the conservatory, but it
ought always to be adapted to the style of the mansion of which it is
a prominent appendage. Some very pleasing examples are to be met with
which have the form of a parallelogram with a lightly-rounded roof;
others of appropriate character are square or nearly so, with a
ridge-and-furrow roof. Whatever the form, there must be light in
abundance; and the shade both of buildings and of trees must be
avoided. A southern aspect, or one varying to south-east or
south-west, is preferable; if these aspects cannot be secured, the
plants selected must be adapted to the position. The central part of
the house may be devoted to permanent plants; the side stages and open
spaces in the permanent beds should be reserved for the temporary
plants.

The _Greenhouse_ is a structure designed for the growth of such exotic
plants as require to be kept during winter in a temperature
considerably above the freezing-point. The best form is the
span-roofed, a single span being better even than a series of spans
such as form the ridge-and-furrow roof. For plant culture, houses at a
comparatively low pitch are better than higher ones where the plants
have to stand at a greater distance from the glass, and therefore in
greater gloom. Fig. 3 represents a convenient form of greenhouse. It
is 20 ft. wide and 12 ft. high, and may be of any convenient length.
The side walls are surmounted by short upright sashes which open
outwards by machinery a, and the roof is provided with sliding upper
sashes for top ventilation. The upper sashes may also be made to lift,
and are in many respects more convenient to operate. In the centre is
a two-tier stage 6 ft. wide, for plants, with a pathway on each side 3
ft. wide, and a side stage 4 ft. wide, the side stages being flat, and
the centre stage having the middle portion one-third of the width
elevated 1 ft. above the rest so as to lift up the middle row of
plants nearer the light. Span-roofed houses of this character should
run north and south so as to secure an equalization of light, and
should be warmed by two flow, and one or two return 4-in. hot-water
pipes, carried under the side stages along each side and across each
end. Where it is desired to cultivate a large number of plants, it is
much better to increase the number of such houses than to provide
larger structures. The smaller houses are far better for cultural
purposes, while the plants can be classified, and the little details
of management more conveniently attended to. Pelargoniums, cinerarias,
calceolarias, cyclamens, camellias, heaths, roses and other
specialities might thus have to themselves either a whole house or
part of a house, the conditions of which could then be more accurately
fitted to the wants of the inmates.

The lean-to house is in most respects inferior to the span-roofed; one
of the latter could be converted into two of the former of opposite
aspects by a divisional wall along the centre. Except where space does
not permit a span-roofed building to be introduced, a lean-to is not
to be recommended; but a house of this class may often be greatly
improved by adopting a half-span or hipped roof--that is, one with a
short slope behind and a longer in front.

Where the cultivation of large specimens has to be carried on, a
span-roofed house of greater height and larger dimensions may
sometimes prove useful; but space for this class of plants may
generally be secured in a house of the smaller elevation, simply by
lowering or removing altogether the staging erected for smaller
plants, and allowing the larger ones to stand on or nearer the floor.
The _Plant Stove_ differs in no respect from the greenhouse except in
having a greater extent of hot-water pipes for the purpose of securing
a greater degree of heat, although, as the plants in stove houses
often attain a larger size, and many of them require a bed of coco-nut
fibre, tan or leaf mould to supply them with bottom heat, a somewhat
greater elevation may perhaps be occasionally required in some of the
houses. For the smaller plants, and for all choicer subjects, the
smaller size of house already recommended for greenhouses, namely 20
ft. wide and 12 ft. high, with a side table of 4 ft. on each side, a
pathway of 3 ft. and a central stage on two levels of 6 ft. wide, will
be preferable, because more easily managed as to the supply of heat
and moisture. It will be seen (fig. 4) that along the ridge of the
roof a raised portion or lantern light b, b is introduced, which
permits of the fixing of two continuous ventilators, one along each
side, for the egress of heated and foul air, openings a, a being also
provided in the side walls opposite the hot-water pipes for the
admission of pure cold air. This type of house is also very suitable
for greenhouse plants, but would not need so much heating apparatus.
Three or four rows of flow and return pipes respectively will be
required on each side, according to the heat proposed to be
maintained.

In their interior fittings plant stoves require more care than
greenhouses, which are much drier, and in which consequently the
staging does not so soon decay. In stoves the stages should be of
slate or stone where practicable, and the supports of iron. These
should be covered with a layer of 2 or 3 in. of some coarse gritty
material, such as pounded spar, or the shell sand obtained on the
sea-coast, on which the pots are to stand; its use is to absorb
moisture and gradually give it out for the benefit of the plants. The
pathways should be paved with tiles, brick or stone, or made of
concrete and cement, and the surface should be gently rounded so that
the water required for evaporation may drain to the sides while the
centre is sufficiently dry to walk upon; they should also have brick
or stone edgings to prevent the water so applied soaking away at the
sides and thus being wasted.

_Fruit Houses._--The principal of these are the vinery, peach house, cucumber and melon house and orchard house. These, or a portion of them, especially the vineries and peacheries, are frequently brought together into a range along the principal interior or south wall of the garden, where they are well exposed to sun and light, an ornamental plant house being sometimes introduced into the centre of the range in order to give effect to the outline of the buildings. When thus associated, the houses are usually of the lean-to class, which have the advantage of being more easily warmed and kept warm than buildings having glass on both sides, a matter of great importance for forcing purposes.

The _Vinery_ is a house devoted to the culture of the grape-vine,
which is by far the most important exotic fruit cultivated in English
gardens. When forming part of a range a vinery would in most cases be
a lean-to structure, with a sharp pitch (45-50 deg.) if intended for
early forcing, and a flatter roof (40 deg.) with longer rafters if
designed for the main and late crops. (1) The _lean-to_ (fig. 5) is
the simplest form, often erected against some existing wall, and the
best for early forcing, being warmer on account of the shelter
afforded by the back wall. In this house the principal part of the
roof is a fixture, ventilation being provided for by small lifting
sashes against the back wall, and by the upright front sashes being
hung on a pivot so as to swing outwards on the lower side. The
necessary heat is provided by four 4-in. hot-water pipes, which would
perhaps be best placed if all laid side by side, while the vines are
planted in front and trained upwards under the roof. A second set of
vines may be planted against the back wall, and will thrive there
until the shade of the roof becomes too dense. (2) The _hip-roofed_ or
three-quarter span (fig. 6) is a combination of the lean-to and the
span-roofed, uniting to a great degree the advantages of both, being
warmer than the span and lighter than the lean-to. The heating and
ventilating arrangements are much the same as in the lean-to, only the
top sashes which open are on the back slope, and therefore do not
interfere so much with the vines on the front slope. In both this and
the lean-to the aspect should be as nearly due south as possible.
Houses of this form are excellent for general purposes, and they are
well adapted both for muscats, which require a high temperature, and
for late-keeping grapes. (3) The _span-roofed_ (fig. 7), the most
elegant and ornamental form, is especially adapted for isolated
positions; indeed, no other form affords so much roof space for the
development of the vines. The amount of light admitted being very
great, these houses answer well for general purposes and for the main
crop. The large amount of glass or cooling surface, however, makes it
more difficult to keep up a high and regular temperature in them, and
from this cause they are not so well adapted for very early or very
late crops. They are best, nevertheless, when grapes and ornamental
plants are grown in the same house, except, indeed, in very wet and
cold districts, where, in consequence of its greater warmth, the
lean-to is to be preferred. This type of house, cheaply constructed,
is in general use for raising grapes for market.

The _Peach House_ is a structure in which the ripening of the fruit is
accelerated by the judicious employment of artificial heat. For early
forcing, as in vineries, the lean-to form is to be preferred, and the
house may have a tolerably sharp pitch. A width of 7 or 8 ft., with
the glass slope continued down to within a foot or two of the ground,
and without any upright front sashes, will be suitable for such a
house, which may also be conveniently divided into compartments of
from 30 to 50 ft. in length according to the extent of the building,
small houses being preferable to larger ones. As a very high
temperature is not required, two or three pipes running the whole
length of the house will suffice. The front wall should be built on
piers and arches to allow the roots to pass outwards into a prepared
border, the trees being planted just within the house. Abundant means
of ventilation should be provided.

For more general purposes the house represented in fig. 8 will be
found more useful. One set of trees is planted near the front, and
trained to an arched trellis b. Another set is planted at the back,
and trained on a trellis c, which is nearly upright, and leans against
the back wall; or the back wall itself may be used for training. There
are no upright front sashes, but to facilitate ventilation there are
ventilators d in the front wall, and the upper roof sashes are made to
move up and down for the same object. Two or three hot-water pipes are
placed near the front wall. The back wall is usually planted with
dwarf and standard trees alternately, the latter being temporary, and
intended to furnish the upper part of the trellis, while the permanent
dwarfs arc gradually filling up the trellis from below. In any case
the front trellis should stop conveniently short of the top of the
sashes if there are trees against the back wall, in order to admit
light to them. They would also be better carried up nearly parallel to
the roof, and at about 1 ft. distant from it, supposing there were no
trees at the back.

A span-roofed house, being lighter than a lean-to, would be so much
the better for peach culture, especially for the crop grown just in
anticipation of those from the open walls since a high temperature is
not required. A low span, with dwarf side walls, and a lantern
ventilator along the ridge, the height in the centre being 9 ft.,
would be very well adapted for the purpose. The trees should be
planted inside and trained up towards the ridge on a trellis about a
foot from the glass, the walls being arched to permit the egress of
the roots. A trellis path should run along the centre, and movable
pieces of trellis should be provided to prevent trampling on the soil
while dressing and tying in the young wood.

The _Forcing House_.--Whenever continuous supplies of cucumbers,
melons and tomatoes are required, it is most convenient to grow them
in properly constructed forcing houses. Span-roofed houses (fig. 9)
arc probably the most useful for the purpose. They are usually 12 to
14 ft. wide, by 10 to 12 ft. high, and of any convenient length.
Heating is effected by means of hot-water pipes below the beds, and
against the side ventilators. The walls bordering the central paths
are arched or clotted to admit heat from the chambers below the beds.
Side pipes are occasionally dispensed with, heat being obtained by
means of slots at the back of the beds, communicating with the
chambers. The beds are also of use for plunging pot plants.
Ventilation is provided at sides and top.

Pits and frames of various kinds are frequently used for the
cultivation of cucumbers and melons, as well as hot beds covered by
ordinary garden frames. In these cases the first supply of heat is
derived from the hot bed made up within the pit. When the heat of the
original bed subsides, linings of fermenting dung must be added, and
these must be kept active by occasional turnings and the addition of
fresh material as often as required. It is better, however, to effect
both top and bottom heating by hot-water pipes.

_Orchard Houses_ are span-roofed or lean-to structures, in which
various fruits are cultivated without the aid of artificial heat.
Peaches, nectarines, apricots, cherries and the more tender varieties
of plums and pears succeed well in houses of this kind. The types of
houses in general use are substantially as shown in fig. 7, for
span-roofed, and as fig. 5, for lean-to; in each case without the
heating apparatus. The orchard house is among the most generally
useful of all garden structures. These houses require careful
management in early summer so as to induce the more delicate varieties
of peaches and nectarines to complete and ripen their growth before
cold, sunless weather sets in.

In commercial establishments where utility is of more importance than
ornament, the glass houses and hot water apparatus are not of so
elaborate a type as indicated in the foregoing remarks, and in many
cases excellent produce is grown in structures more or less
dilapidated. In some places movable greenhouses have been erected for
market purposes, so that the soil may be exposed to the sweetening
effect of the weather, when the glass roof is moved to an adjoining
patch.

_Pits and Frames._--These are used both for the summer growth and winter protection of various kinds of ornamental plants, for the growth of such fruits as cucumbers, melons and strawberries, and for the forcing of vegetables. When heat is required, it is sometimes supplied by means of fermenting dung, or dung and leaves, or tanner's bark, but it is much more economically provided by hot-water pipes. Pits of many different forms have been designed, but it may be sufficient here to describe one or two which can be recommended for general purposes.

An excellent pit for wintering bedding-out plants or young greenhouse
stock is shown at fig. 10. It is built upon the pigeon-hole principle
as high as the ground level a, a, and above that in 9-in. brickwork.
At a distance of 9 in. retaining walls b, b are built up to the ground
level, and the spaces between the two are covered by thick boarding,
which is to be shut down as shown at c in cold weather to exclude
frost, and opened as shown at d in mild weather to promote a free
circulation of air through the pit. The height of the pit might be
reduced according to the size of the plants; and, to secure the
interior against frost, flow and return hot-water pipe e should pass
along beneath the staging, which should be a strong wooden trellis
supported by projections in the brickwork. The water which drains from
the plants or is spilt in watering would fall on the bottom, which
should be made porous to carry it away. For many plants this under
current of ventilation would be exceedingly beneficial, especially
when cold winds prevented the sashes from being opened. A pit of this
character may be sunk into the ground deeper than is indicated in the
figure if the subsoil is dry and gravelly, bat in the case of a damp
subsoil it should rather be more elevated, as the soil could easily be
sloped up to meet the retaining wall.

_Frames._--Frames (fig. 11) should be made of the best red deal, 1(1/4)
in. thick. A convenient size is 6 ft. wide, 24 in. high at the back
and 15 in front; and they are usually 12 ft. long, which makes three
lights and sashes, though they can be made with two lights or one
light for particular purposes. Indeed, a one-light frame is often
found very convenient for many purposes. The lights should be 2 in.
thick, and glazed with 21 oz. sheet glass, in broad panes four or five
to the breadth of a light, and of a length which will work in
conveniently and economically, very long panes being undesirable from
the havoc caused by accidents, and very short ones being objectionable
as multiplying the chances of drip, and the exclusion of light by the
numerous lappings; panes about 12 in. long are of convenient size for
garden lights of this character. In all gardens the frames and lights
should be of one size so as to be interchangeable, and a good supply
of extra lights (sashes) may always be turned to good account for
various purposes.

Span-roof garden frame (fig. 12) may under some circumstances be
useful as a substitute for the three-light frame. It is adapted for
storing plants in winter, for nursing small plants in summer and for
the culture of melons and other crops requiring glass shelter. These
frames are made 11 in. high in front, 22 at the back and 32 at the
ridge, with ends of 1(1/2)-in. red deal; the sashes, which are 2 in.
thick, open by gearing, the front and back separately. The lights are
hinged so that they can be turned completely back when necessary. This
more direct and ready access to the plants within is one of the
principal recommendations of this form of pit.

_Mushroom House._--Mushrooms may be grown in sheds and cellars, or even in protected ridges in the open ground, but a special structure is usually devoted to them. A lean-to against the north side of the garden wall will be found suitable for the purpose, though a span-roofed form may also be adopted, especially if the building stands apart.

The internal arrangement of a lean-to mushroom house is shown in fig.
13. The length may vary from 30 ft. to 60 ft.; a convenient width is
10 ft., which admits of a 3(1/2) ft. central path, and beds 3 ft. wide
on each side. The shelves should be of slate a, a, supported by iron
uprights b, b, each half having a front ledge of bricks set on edge in
cement c, c. The slabs of slate forming the shelves should not be too
closely fitted, as a small interval will prevent the accumulation of
moisture at the bottom of the bed. They may be supported by iron
standards or brick piers, back and front, bearing up a flat bar of
iron on which the slates may rest; the use of the bar will give wider
intervals between the supports, which will be found convenient for
filling and emptying the beds. The roof may be tiled or slated; but,
to prevent the injurious influence of hot sun, there should be an
inner roof or ceiling d, the space between which and the outer roof e
should be packed with sawdust. A hot-water pipe f should run along
both sides of the pathway, close to the front ledge of the lowest
beds. The different shelves can be planted in succession; and the
lower ones, especially those on the floor level, as being most
convenient, can be utilized for forcing sea-kale and rhubarb.