Many of my friends, who are commencing floricultural persuits as an amusement for their leisure hours, are continually applying to me, as an old amateur, to know how and when to give water to plants cultivated in pots. The subject is perhaps to the novice, one of the greatest troubles that besets him; although to the experienced, one of the least so. A few general instructions, I think, may elucidate it sufficiently to guide in some measure the young amateur, although from its nature, there is no possibility of giving specific rules by which to act.

All plants, because they are in pots, by no means require the same supplies of water; and consequently the indiscriminate watering of the general collection of plants, which usually constitutes the amateur's collection, is at all times injudicious, and frequently very injurious to their well doing. A little reflection will satisfy any one that this must be so. In their natural state, some of our floral favorites are inhabitants of hills, and others of swamps and valleys; some of light sandy soil, others of stiff clay, or of decayed vegetable matter; some again are evergreen, growing more or less all the year; others are deciduous and dormant for many weeks together; some natives of places where the rain falls for months, others of a humid moist climate. From these considerations it must be evident that for plants to be preserved in health and vigor, when confined to the limit of a small pot, upon the contents of which alone it is dependent for the support of vegetable life, the supply of water must be varied to the different species, so as to approximate in some degree to that condition of growth, for which they have been respectively fitted by nature.

The instructions I am about to give will be better understood, by making some general divisions of the subject, and I shall therefore treat of watering under the following heads:

1. Evergreens

And these must be treated as regards such as are succulent, as Geraniums, etc. - such as are ligneous as Camelias.

2. Deciduous Plants

As Fuchsias, etc.

3. Herbaceous Plants

As Calceolarias, etc.

4. Bulbous rooted plants.

5. Aquatics.

There are are a few general principles applicable to all plants, which I shall in the first place notice.

The great point is, to keep the earth in the pot in such a state of moisture, as will supply all the wants of the plant and no more; with this object, the following remarks must be constantly borne in mind.

Whenever water is given to a pot, it should be in a sufficient quantity to wet the soil equally through. If the earth in which the plant is potted is, in order to suit that particular plant, of a stiff loamy texture, it will require less frequent supplies of water than if it be light sandy loam, or composed principally of leaf-mould or decayed vegetable matter.

If the quantity of roots in a pot is small, with reference to the size of the pot, much less water is required than when the pot is full of roots; because in the former case, the roots will gather moisture for some time from the surrounding soil; in the latter, all the water that is not taken up by the roots soon after the plant is watered, drains away.

If a plant, whose roots do not nearly extend to the sides of a pot, be watered more frequently than the roots absorb it, the surrounding soil becomes saturated with water, which remains in a wet state, wholly unfit for vegetation; the result of which will be decay of the roots of the plant.

When plants have been cutback or pruned, the supply of water to them, should always be considerably lessened; because, the quantity of roots remaining the same, they have, until new shoots are made, a much less quantity of branches and leaves to support, and the want of leaves cuts off the source by which the water is dissipated in the atmosphere after it has supplied the wants of the plant.

When plants are growing rapidly, that is making their annual supply of shoots for the year, and throwing out and perfecting their flower buds, they require much more water than when in a dormant state.

With reference to my last remark, it must always be remembered, that inasmuch as both indigenous and exotic plants are very variable, in the seasons of the year at which the above occurrence takes place, so the use of the watering pot must be regulated by the judgment of the florist, and not by the season of the year, solely; although, undoubtedly both such plants as are dormant, as well as such as are vigorous in their growth in the summer season, will require a more liberal supply, (having regard to their habit of growth) than the same species would require in the winter under the same circumstances.

Thus much I wish to inculcate as general principles; and I will now proceed to make some remarks on the treatment under each of the above heads.

1st. Evergreens

Such as are succulent; such as are ligneous. The succulent class of evergreens require a liberal supply of water during their growing state, (particularly such of them as bloom in the hot months of the year,) but a very scanty supply in winter. Geraniums for instance, when they are shooting up for bloom, should be watered on the surface of the soil, at least three or four times a week; then in another month, every morning; and syringing over head will be found daily beneficial to this, and all similar classes of plants at this stage of their growth. In the hot summer months, they will require water morning and evening. In autumn, the quantity of water must be materially lessened; and from the setting in of winter until the middle of February, it is scarcely possible (if they are kept during that time in a place no warmer than is sufficient just to exclude frost,) to keep them too dry. If succulent plants are found to turn black and mouldy, either in the stem or leaf, that is evidence that they have had too much water, with reference to the temperature at which they have been kept. The principal things, for geraniums and other succulents of similar growth, in the winter months, are light and sun, with all the air that can be given them without exposure to frost.