As the trying season is now approaching for all plants that are kept in rooms, especially those that are desired to have a flourishing aspect through the winter, a few general instructions (although they may have been previously advanced) will perhaps be desirable to all those who are engaged in this interesting occupation, which forms a luxury through the retired hours of a winter season, and with very little attention many are the beauties of vegetative nature that will be developed to the gratification of every reflecting mind. The following is a routine of every day culture.

Do not at any time admit air (except for a few moments) while the thermometer is below 32° exposed in the shade.

In time of very severe frosts the plants ought to be withdrawn from the window to the centre of the room during night.

Never give water until the soil in the pots is inclining to become dry, except for Hyacinths and other Dutch bulbs that are in a growing state, which must be liberally supplied.

Destroy all insects as soon as they appear; for means of destruction see next month.

Give a little air every favourable opportunity, (that is, when the thermometer is above 33° exposed in the shade,) by putting up the window one, two or three inches, according to the state of the weather.

Clean the foliage with sponge and water frequently to remove all dust, &c. The water thus used must not exceed 96° or blood-heat, but 60° is preferable.

Turn the plants frequently to prevent them growing to one side.

Roses of the daily sort may be obtained early by having them in a warm room, that has a south window, and as soon as they begin to grow, admit air in small portions about noon every day that the sun has any effect. Such must be well supplied with water.

CamÉllias, when in bud and flower, should never be allowed to become the least dry, neither confined from fresh air. The effects would be that the buds would become stinted, dry, and drop off. Therefore, to have these in perfection, attend strictly to watering. Give frequent airings, and wash the leaves once in two weeks with water. Never keep them above one day in a room, where there is a strong coal fire, and not above two days where wood is used as fuel. The most of CamÉllias will bear 3° of frost without the smallest injury, so that they are easier kept than Geraniums, except when they are in bloom. In that state frost will destroy the flowers. The air of a close cellar is destruction to the buds.

Bulbs in glasses must be supplied with fresh water once a week, in which period they will inhale all the nutritive gas that they derive from that element, if they are in a growing state.

ON THE CONSTRUCTION OF A HOT-HOUSE.

There have been many plans devised and visionary projects offered to the public as the best for a well regulated Hot-house. As we intend forming one for practical purposes, we shall adopt a convenient size, have flues for the conveyance of heat, and coal or wood for fuel.

Site and Aspect.—The house should stand on a situation naturally dry, and if possible sheltered from the north west, and clear from all shade on the south, east and west, so that the sun may at all times act effectually upon the house. The standard principle as to aspect is to set the front directly to the south. Any deviation from that point should incline to east.

Dimensions.—The length may be from ten feet upwards; but if beyond thirty feet, the number of fires and flues are multiplied. The medium width is from twelve to sixteen feet. Our directions will apply to the two extreme points, viz. thirty feet by sixteen, and in height at back from twelve to eighteen feet; the height in front six feet, including about three feet in brick basement to support the front glass, which will be two and a half feet, allowing six inches for frame work.

Furnace and Flues.—It is of great importance to have these erected in such a manner as will effectually heat the house. The greatest difficulty is to have the furnace to draw well. As workmen are not generally conversant on the subject, nor yet understand the effect or distribution of heat in these departments, we will give minute details on their construction. The furnace should be outside of the house, either at back or end; the former is preferable, circumstances not always allowing it on the other plan. Dig out the furnace hole, or what is termed stock hole, about five feet deep. Let the door of the furnace be in the back wall of the house, thereby having all the heated building inside, that no heat may be lost. The brick work round the furnace should be from fifteen to eighteen inches thick, laying the inside with fire-brick. The furnace will require to be two and a half feet long, ten inches wide, and one foot high, before the spring of the arch and clear of the bars; leave one foot for an ash pit, then lay the bars. They should be sixteen inches long, one inch broad on the upper side, two inches deep, and two eighths broad on the lower side, and with the door and frame should be cast iron. Half an inch between each bar will be sufficient. The flue should rise from the furnace by a steep declivity of about two feet, and pass the door of the house (without a dip), when it must be elevated above the level of the floor of the house along the front, and at the opposite end of the house must dip to pass the door. The dip must not be lower than the top of the furnace, and should be of a concave form, (avoiding acute angles.) Lead it along the back to enter the wall over the furnace. When thus taken round the house, the heat will be expanded before it passes off, The inside of the flues should be about six inches wide and eight inches deep; plaster the bottom of it, but no other part, as plaster is partially a non-conductor. The above description is for burning anthracite coal, but where wood is to be the fuel, the furnace and flues must be one half larger. We have been particular in the description of furnace bars, as those generally used are miserable substitutes. Circumstances may cause the furnace to be placed at the end or front of the house. In either case the stock hole will not require to be so deep; or where there is only one door in the house a stock hole three and a half feet deep will be enough, which should be built like a cellar to keep out any under water. In all instances pass the first flue to the front of the house, over which have a close shelf eight inches clear, covered with two inches of sand, and by keeping it moist will afford a very congenial heat to young valuable plants. Likewise over the furnace have a frame in the same manner, which will be found valuable. Any part of the furnace or flue that is under the floor of the house, should have a vacuity on both sides to let the heat pass upward.

Bark Pit.—We consider such an erection in the centre of a Hot-house a nuisance, and prefer a stage, which may be constructed according to taste. It should be made of the best Carolina pine, leaving a passage round the whole to cause a free circulation of air. The back and end paths should be about two feet wide, and the front three feet. The angle of the stage should be parallel with the glass, having the steps from six inches to one foot apart.

Where there are some large plants, they may stand on the floor behind the stage, or on tressels, according to their height.

Angle of the glazed roof.—The pitch of the roof is usually varied to agree with the design of the house, and the size of the plants to be grown therein. Where pleasure and ornament are the principal objects, the angle should be about 43°, but a few degrees of inclination either way is of minor importance, the height and elevation being regulated by the size of the plants intended to be cultivated. It is not advisable to shingle any part of the roof on the south aspect.

Materials for glazed frames.—Carolina pine is the best material for the wood work, as it is not so subject to decay from moisture and heat as the other kinds of pine wood. The frames or sashes can be of any convenient length, not exceeding ten feet, and about three and a half or four feet wide, divided so as they can be glazed with glass six inches wide.

Of glazing. The pieces of glass should not exceed six inches by ten, the lappings about one quarter of an inch. The frames ought to have one coat of paint previous to glazing, and all under the glass puttied. Some prefer the lappings to be puttied also. It is our opinion that in a Hot-house these should not be puttied, but in the Green-house the closer they can be made the better.

Of Shutters.—These should be made of half inch white pine, and bound on both ends and sides, having a cross piece in the middle of the same. They ought to be painted once in three years.

ON THE CONSTRUCTION OF A GREEN-HOUSE.

In many respects, the construction of the Green*-house will be the same as the Hot-house, but might be made much more an ornamental object, and could be erected contiguous to the mansion-house, with large folding doors to open at pleasure, and be connected with the drawing-room or parlour. The extent may vary according to the collection to be cultivated.

It was formerly the practice to build these houses with glass only in front, and even to introduce between the windows strong piers of brick or stone: but this is now abolished, and has given way to a light and ornamental style, by which cheerfulness and the desired utility are better consulted. There should be conveniences in the back part of the house, that a free current of air may be obtained whenever desired, which is an essential point. Two or three dark windows will answer the purpose well, if made to open and shut at pleasure.

ON LAYING OUT A FLOWER-GARDEN.

Soil, situation, and ground—Plan.—A soil of common good qualities, moderately light and mellow, will grow most of the hardy herbaceous flowers, and the evergreen and deciduous ornamental shrubs. The situation should not be so low as to be damp and wet, or liable to be inundated, neither so high as to be scorched or dried up by the sun. The surface should be level or moderately sloping, and if unequal, parts of it may be transposed, so as to make gentle inclinations. In regard to form, it may be of any shape, and must be often adapted to local circumstances; but if it is so circumscribed that the eye can at once embrace the whole, it is desirable that it should be of some regular figure.

Of Fences.—Where domestic buildings do not serve as a boundary, either paling or hedge-fence has to be resorted to: we would prefer the former on the north or north-west side, which is of great advantage as a screen from cutting winds. For hedge-fences and their kinds, see page 210. The exotic observed there is ThÙja orientÀlis, Chinese Arbor-vitÆ. The internal fences for shade or shelter to particular compartments, or to afford a diversity of aspect, may be made of Sweetbriar, hardy China roses, Pyrus, red and white, with a few others of a similar nature, all of which must be attended to, to have them in neat order.

Style of dividing the Ground.—This may vary with the extent of the ground, and the object of the cultivator.

The principal designs may be delineated, but one to answer every view and situation, we pretend not to give. In the first place, carry a boundary walk all round the garden, on one or two sides of which it may be straight, the others winding. The intersecting walks should (almost imperceptibly) lead to a centre, but not to cross at right angles, or to have parallel lines, as if divided or laid down by a mathematical scale, which is too formal for the diversification of nature. All walks through these pleasure departments should be winding and enlivening, not continuing any length in one direction.[K] The continuous view of a straight walk is dull and monotonous. The divisions should be highest about the centre, that whatever is planted therein may have effect; and to make a Flower-garden fully interesting, and render it a source of natural information, where free scope might at all times be afforded to employ the leisure hours in mental improvement, there should be a good system of arrangement adopted.

The Linnean system is the most easily acquired. A small compartment laid out in beds might contain plants of all the twenty-four classes, and a few of all the hardy orders, which do not exceed one hundred. Or to have their natural characters more assimilated, the Jussieuean system could be carried into effect by laying down a grass plat, to any extent above one quarter of an acre, and cut therein small figures to contain the natural families, which of hardy plants we do not suppose would exceed one hundred and fifty. The difficulties of this arrangement are, that many of the characters are imperfectly known even to the most scientific. Mr. John Lindley has given additional light on the subject by his last publication. All the large divisions should be intersected by small allies, or paths, about one and a half or two feet wide. These may be at right angles, or parallel, for convenience and order, in making beds, &c. for the various Dutch roots and other flowers. Patches or plats of grass studded with shrubs, deciduous and evergreen, are indispensable, and perhaps one or two grass walks.

Of Walks.—These should have five or six inches of lime and brick rubbish, or broken stone in the bottom, covered with small pebbles, and firmly rolled with a heavy roller, over which lay two or three inches of fine gravel, giving the whole a complete rolling. Walks made on this method will stand well, and be always dry and firm. With regard to breadth, they must be made according to the extent of ground, and vary from three to thirty feet; from four to eight feet is generally adopted.