In the early part of this month the weather generally is very cold and changeable in the middle states, and strict attention, with the greatest caution, will require to be paid to the management of the Hot-house. Most of the tropical plants commence an active state of vegetation; and if checked by temperature or otherwise, they will not recover until midsummer. The thermometer may be kept two or three degrees higher with fire heat than last month; the sun will be more powerful, and this will, in a great degree, increase the vigour of the plants. Air may be admitted when the thermometer rises to 75° or 80°, not allowing it to rise higher than the latter. In giving air, let it be done by the top sashes. It is improper to give it in any way to cause a current, for the external air is very cold, although the sun is more powerful. An inch or two on a few of the sashes, as has been previously observed, will be effectual in keeping the temperature low enough, except the weather is very mild.

With regard to firing, what was said last month may suffice for this. Always recollect that it is preferable to keep out the cold than to put it out. It will frequently happen in the time of intense frost, that the weather is dull. In such cases fire in a small degree is requisite all day.

Heavy snows ought never to be allowed to remain on the shutters while they are on the house. If the snow lies on the sashes one day, the internal heat will dissolve some of it; night coming on will freeze it to the wood work, when it will become a solid mass, and too frequently cannot be separated without much damage. If allowed to remain on for two days, the plants are very much weakened, and the foliage discoloured. Therefore let the snow be cleared off instantly, that no inconvenience may take place.

It will be observed that plants absorb more water this month than last. The quantity given will require to be increased, according to the increase of vegetation and the advancement of the season; but never give it until the soil begins to get dry, and then in such proportion as will reach the bottom of the pot. After the sun has got on the house in the morning is the best time to water, observing all the directions given in January.

OF INSECTS, &c.

Perhaps sufficient observations were given under this head last month; but the importance of keeping these disagreeable visitors out of the house, constrains us to make a few more remarks, and perhaps it may be necessary every month. Man cannot be too frequently guarded against his foes, more especially when they are summoning all their forces, and no profession has more than that of the Horticulturist. Let a strict examination be made about the end of the month for the Red spider; they will be in operation some weeks before their depredations are observed on the foliage. The under side of the leaf is their resort in the first instance, and on such plants as have been already mentioned.

Observe daily the young shoots, in case the Green fly becomes numerous. They give the foliage a very disagreeable appearance, and with most people it is intolerable, before their career is arrested. It also takes a stronger fumigation, which has frequently to be repeated the following day to the same degree, much to the injury of many of the plants, and adding to the disagreeableness of the continued vapour in the house.

OF SHIFTING PLANTS.

The CalceolÀrias that were put in small pots about the beginning or middle of last month, will, if they have done well, require, about the end of this, to be put in pots a size larger.

If any of LilÌum longiflÒrum, SpeciÒsum, or JapÓnicum, are wanted to flower early, and were put in the Hot-house in December, without dividing, those that are to flower will have pushed their flower stems, and can be separated from those that will not flower, and put singly into pots; the two former into five or six inch pots, while the latter require six or seven inch pots. Of those that do not flower, three or four can be put into one pot.

About the end of the month, some of the plants of EurcÚma, AmÓmum, KÆmpfÉria, GlÓbba, Phrynium, CÁnna, ZÍngiber, Hedychium, and others that are on the dry shelf, will be offering to grow. Let them be taken out of their pots, some of their weakest shoots or tubers taken off, and the strong ones repotted: give gentle waterings until they grow freely, then give an abundance.

DionÆa mucÍpula, or Venus fly trap, grows best in the Hot-house, and will, about the end of the month, stand in need of being repotted. This plant is very seldom grown in any degree of perfection, having been always considered a delicate plant in collections. The operator has never had courage to treat it according to its nature in a cultivated state. If it is taken out of the pot, just when beginning to grow afresh, and divested of all the soil, leaving only a few of the young roots, (it is a bulb, and will receive no injury by so doing,) put it in new soil; when potted, place the pot in a saucer with one inch of water in it, giving always a fresh supply, when necessary. A shady and moist situation is best adapted to it; this being repeated every year, it will grow, flower, and seed in perfection.

GesnÉrias, if in small pots, give larger as they advance in growth. This genus requires to be well attended to make them flower well. G. bulbÓsa ought to have a situation in every Hot-house. It is remarkable for its many brilliant crimson flowers, and continues in flower for a length of time. When the bulb begins to push, shake it out of the earth, putting it into a small pot; and, as soon as the roots reach the side of the earth, which will be in about one month, put it in a larger pot, and continue to do so until flowering, which will be about the first of June, observing always to keep the ball of earth entire.

GloriÓsas must be repotted in the beginning of this month. Etymologists have said that this genus is named from the glorious appearance of its flowers. G. supÉrba is the most beautiful and curious. The roots ought to be planted one and a half inch deep, taking care not to break them; if there is a bark bed, place the pots in it. Do not water much until they begin to grow. Where there is no bark bed, put the pots into others three inches larger, filling all round with sand, and place them in the warmest part of the house. Keep the sand moist, which will assist to keep the soil in a moist state. The earth must not have much water. As the plants grow, they will require a more liberal supply; yet it is necessary, at all times, to be moderate in giving it. If well treated, the superb flowers will appear in June or July.

OF CLEANSING PLANTS, HOUSE, &c.

With regard to cleaning the plants. Sprinkling, or syringing, is at all times, to a greater or less degree, necessary. The plants will, in this compartment, be in their first stage of growth, and, if dust or foulness be permitted to lodge on their foliage, the pores will be obstructed, the plants will become unhealthy, and the growth of insects increased.

Let all moss, litter, decayed leaves, or weeds, be cleared out of the house, the earth in the pots stirred up with a round pointed stick, and fresh earth given where required, that the air may operate therein freely.

The house ought always to be sprinkled before being swept, to prevent the dust rising.

Attend to the bulbous roots as directed last month, such as Hyacinths, Narcissus, &c.