Pots and Potting
Pots are amongst the most essential of garden utensils, and on the proper execution of Potting depends materially the success attained in plant culture. Potting is a general term meant to imply that a plant is being first placed in a Pot, or transferred from one size to another for providing additional rooting space. Pots are generally made of clay, and as this varies in different localities, so do the articles made from it; from different potteries, too, the sizes and shapes vary considerably. In making Pots, a certain quantity of clay is called a "cast"; this is worked to make the number by which the sizes are in many places distinguished--thus, 48's, 32's, 24's, &c.--the two lesser numbers taking respectively the same quantity of clay to the cast as the other, but the Pots being in two larger sizes. In other places, the sizes are known by inches, as 5in., 6in., 8in., and so on. All Pots are made, or should be made, wider at the top than at the bottom; this is an essential provision for allowing the balls to be turned out without becoming broken. If the shape were cylindrical, or the bottom wider than the top, this would be an impossibility, as the ball becomes compressed inside to the same shape, and, in due course, is usually permeated with roots. In order to supply plants with an amount of soil and root space somewhat in proportion to their several requirements, numerous sizes of Pots are indispensable. There are various sorts and shapes made, the most being of the ordinary description; while special ones are made for Orchids, and for other purposes, such as forcing Rhubarb and Seakale. Ordinary Pots are always provided with a hole at the bottom, for the escape of water; in some of the larger sizes, two or three in addition are made at the side, near the bottom. A rim is generally made round the top, but, in some potteries, small sizes are made without; one of the objects being that a larger quantity may be stood in a given space after they are filled with plants--the absence of rims allowing them to be arranged in a smaller compass. Orchid-pots are of greater width, in proportion to depth, than others of ordinary make; they are also much perforated at the bottom and sides, to insure the porosity and perfect drainage which these plants require, and to allow spaces for their roots to grow through and attach themselves to the outside surface. Blanching-pots used for forcing Rhubarb and Seakale are large and deep, and are provided with a movable top, for affording access to the interior without lifting off the whole. They are inverted over the plants in the reserve ground, or elsewhere in the open garden, and covered with leaves or fermenting material. These Pots are specially useful where forcing or forwarding is only requisite in spring, and not throughout the winter.
Some few cultivators favour glazed Pots in preference to those of the usual description, which are unglazed; but they are much higher priced, and, for several reasons, are not to be generally recommended. Glazed Pots do not need much attention to keep them clean, and plants grown in them require less water than in the others; but there is not the same degree of cohesion between the soil and Pot, which is most desirable for success in plant culture. Besides the sorts of Pots already referred to, there are others known as the Alpine or Double-sided, and the Double-rimmed. The Alpine Pot is virtually two, one inside the other, a narrow space being allowed between them for filling with water, damp sand, or moss, for the purpose of preventing evaporation from the soil in which the plant grows. This end may be gained, to a certain extent, by the use of moss and two ordinary Pots of different sizes, one inside the other; but, if water is intended for filling the space between, only the best ware, as used for the Alpine Pot, would suit: the ordinary sort would be too porous. Double-rimmed Pots are used for propagating, when bell glasses are employed; an extra rim being made for the reception of the glass, which admits of all the space inside being occupied with cuttings. These Pots have few practical advantages, and are not extensively used. Shallow Pots are now in great demand, especially for Orchids: they may be suspended like baskets, and, being shallow, are often called pans.
Potting forms a most important part of the routine work of gardening; it has to be practised more or less almost daily in all extensive establishments. The work varies infinitely with the numerous subjects grown, as do also the requirements of different plants. Some need very firm, and others only moderately firm, Potting; and, again, one sort of plant will bear frequent, and what is termed large, shifts, while certain death would result with another were it similarly treated. A few general remarks may be given on this subject here; but it will be unnecessary to enter far into details, since these are given elsewhere under the several plants which specially require them, and the practice is one which can only be fully learned by long experience and close observation. The provision of proper and efficient drainage is always of great importance, and forms the first part of the Potting process, except the preparation of soil and Pots. These latter should always be used clean and dry; they are best if washed; but when this is impracticable, a thorough rubbing-out is most essential. It may not be generally known that plants never turn out properly from Pots that are wet or dirty at the time they are used; sometimes, it is impossible to separate balls of earth without breaking them all to pieces, and so destroying, or at least injuring, the roots. Dry, clean Pots, and good drainage, are, therefore, important preparations for Potting. The proper soil will, of course, vary with the numerous plants about to be inserted therein, but a rule of general application is that of having it just sufficiently moist at the time of using. Wet soil cannot be properly worked in around the roots, and plants never succeed so well when placed in it; while a soil too dry cannot be rightly solidified in Potting, and is difficult to moisten through afterwards by watering. Soft-wooded plants may invariably have more soil added to their roots at one time than those of a hard-wooded nature: where Pots nearly as large again may be safely used with the one, the other would only require the least additional space. Spring is the season when Potting operations are naturally most active, as the period when new growth commences in so many plants, after comparative inactivity, is a good time to provide them with additional root-space or whatever other attention they may require. In Potting hard-wooded plants of any description, the old ball should never be placed lower in the soil than it has previously been; if the stems are buried, certain death will, in most cases, be the result. These remarks apply more particularly to Heaths and numerous subjects of a like tender nature that are natives of Australia, the Cape, &c. In contrast to the class of plants just referred to, there are others which may have their stems buried at the time of Potting without the least fear of injury; these are mostly of the softwooded class, and need not be severally mentioned. Another point for reference is that of properly filling-in the space all round the old ball of earth. It is not an unfrequent occurrence, on turning a plant out after it has been shifted, to find the space round the lower part of the old ball only partly filled; this shows very inferior workmanship. If a plant is potted as it should be, all the additional soil given will have been rendered equally firm with the hand or hand-rammer, as the case may be, and thus the old and new soil will unite. Plants should never be Potted when the balls are dry or approaching dryness: they seldom get soaked afterwards when surrounded with soil of a moist nature, through which the water, when given, will pass readily, and leave the dry part to remain as before. The balls of earth and the soil used should, therefore, be as near alike, regarding moisture, as may be practicable; either extreme must be avoided.
A strong Potting-bench is always requisite for the proper execution of work upon it. Unless the bench is firm, Potting on it is unsatisfactory, as the soil cannot be pressed or rammed unless the Pot rests upon a solid base. The shape and strength of material best suited for a strong Potting-bench are indicated. Such a one made strong would last a very long time, and could be moved about to any part of the garden, if desired.