As many amateurs have a greenhouse which they conduct themselves, a few words of advice may not be thrown away. The writer often sees a greenhouse sadly neglected from the want of correct information on the part of the owner; the plants are overgrown and covered with mildew, untidiness reigns around, and the structure, which, properly managed, would be an ornament to the garden, is almost a blemish to it. At this season every preparation should be made for the months which must intervene before the house can be emptied. What has to be done in the way of cleaning and general arrangement should be done at once, and the following observations, if attended to, will help to secure for the amateur all the benefit the greenhouse is calculated to give.

If not done before, the house should receive a thorough cleaning, and for this purpose the plants must be turned out, or if the weather will not permit this, they may be crowded together at one end, while the other receives the requisite purification. The glass, paint, and floor should be scrupulously submitted to a woman competent to do the thing in a business-like way. Every corner should be scraped out, that all insects and their eggs may be destroyed. As pots acquire growths of fungous productions, an application of soap and water will be of service to them. This cleanliness will be found of great value, and will promote the well-being of the plants in a high degree during the winter months, when the dampness of the atmosphere is more to be dreaded than frost. Mildew, mouldiness, et hoc genus omne, delight in dirty places, to say nothing of the thousands of insects which the smallest greenhouse can harbor in its corners and crevices.

The next process is the arrangement of plants for the winter, a matter requiring a measure of judicious thoughtfulness. The plants of an amateur may be classed into two kinds, those which are required to grow, and those for which a state of rest is more desirable. The former must have the best of the light and warmth, while the latter may be placed in the situations having the least of these advantages. It is presumed that artificial heat is not to be applied, except for the purpose of excluding frost; for if the house is kept too warm, no plants can be put into shady places with impunity. The stock for bedding out next spring should be kept as dormant as possible, and in a house without a fire this may be done by putting the pots on the floor, and giving no more water than sufficient to keep the foliage from withering. Plants to bloom during the winter, or early in spring - in fact, all which are required to grow now - should be arranged as near the light as possible. In the arrangement of plants in a house, care must be taken not to allow the foliage to become crowded; and to prevent this productions of low stature should be placed between those which are taller. By this kind of sorting, the space will be economised, and a far larger number of pots got in and kept healthy.

It should have been stated above, that it is indispensable that the roof should be water-proof, for the drip will seriously incommode you, if it is allowed to come in.

Let it be seriously impressed upon the possessor of a greenhouse for general purposes to be as liberal as possible in the admission of air on every practicable occasion. No one thing is so inimical to the health of plants as the want of fresh air. A free movement among the leaves, occasioned by the wind, is always to be desired, and there are no days, except when frost exists, when this may not be gained. It is surprising what a dread exists of fresh air among a large class of persons. They exclude it from their bed-rooms, and on the same principle shut it out from their greenhouses, with the same result in both oases. To drive out damp, or to prevent its entrance, no plan is so effectual as that now recommended.

Ordinary frosts may be resisted without the application of fire-heat, if care is taken to cover up the house with some material which is a non-conductor of heat. If in any case a sharper frost than was anticipated should occur in the night, leave on your covering until the sun has risen some time, or until you have ascertained that any frozen foliage is thawed. It is astonishing how much a tender plant will stand of cold, if light, and especially solar rays, are excluded until the thawing is over. In all cases the object is not to give heat but to exclude frost, and to this end the skill and attention of the amateur should be directed.

In the present state of the garden in general, while the foliage remains unmoved, and flowers are still brilliant, every amateur should take a survey of his domain, whether extensive or limited, for purposes of future alteration and improvement. Time will be well employed in noting matters which admit of a better arrangement than they have yet received, and it is highly important that the various effects produced by the position and filling up of flower beds, and the allocation of trees and shrubs, should be marked. In relation, for instance, to close planting, this is the time to observe its injurious consequences, and to determine to correct them. In winter, when the branches are destitute of their umbrageous coverings, there appears to be space enough for each tree and shrub to revel in; but in the autumn the conviction made by a survey is very different. Some plants touch each other, others are becoming intertwined, others are fast hastening to incommode their neighbours. Now, although it would have been wiser to have planted at a proper distance at first, the quicker the evil is remedied the better it will be.

Mark those trees which are thus threatened with shortness of house-room, and let them be moved with care, so that they may suffer as little as possible.

If the cropping of a kitchen garden is observed, and the arrangements which have existed during the year in the plantations of Gooseberries, Currants, Raspberries, and Strawberries, it will be found that the best vegetables and finest fruit have been secured where the most liberal space has been allowed for sun and air. A wet season teaches capital lessons on this subject, for it is then seen how shade and contracted quarters injure vegetation and deprive fruits of their proper flavour. One of the last lessons learned by the gardener is, that if we are generous to Nature, she will be generous to us, but that if we restrict her she is amply revenged. Make your observations now, and this fact will be impressed upon your memory. Crops of Cabbages or Broccolies, rows of Peas and Beans, etc., which have been crowded together, are now the dens of mildew and insects, while those provided with plenty of room have been kept in health by sweet air and bright suns. Determine which rows of Raspberries shall be rooted up, which Strawberry plants will be better away, and, having formed the resolution, do not forget to execute it when the desolations of winter have contracted the productions, and seem to give them space enough.

The effects produced by the various colours of flowers in combination and in contrast, may now be advantageously recorded, either for imitation or alteration next year. For example, I have in my garden some six-year-old scarlet Geraniums, which I annually plant in various situations, generally surrounding them with flowers of a more shrubby growth, and of a contrasted colour. This year I planted round these tall stems some seedlings of a minor Convolvulus, of a much darker blue than the common variety, and as its growth has been very rampant, the plants have been twined with the branches of the Geraniums; The effect of the brilliant blues and deep scarlets, and the light and dark green of the foliage has been very striking, and I shall endeavour to adopt the same arrangement next year. So in reference to other things. Some combinations I have found to be any thing but graceful, while others are worthy of being perpetuated. These various results will fade from the memory unless now distinctly noticed, and the benefit of experience in this manner will be lost.

Nothing teaches like Nature: and the amateur may receive fine lessons on taste by watching and criticising her equisite painting. Observe the hedgerows at various seasons, and you will learn what different new arrangements your parterres admit of. Bend your attention to the lights and shades produced by the ever-varying combinations of the fields and the woods, and you may transfer some beauties to your shrubberies. The eye and the heart in this way will find plenty to do, and you will become not only an admirer but also a co-adjutator of Flora, the tasteful observer of whose footsteps will often be able to heighten the beauty of his mistress by a chaplet of his own creation.