This section is from the book "The Gardener V3", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Probably, of all other professions, that of the gardener has most to do with necessary evils, which are ever the cause of anxiety and trouble to him, from the time he gets up in the morning till he lays him down to rest at night: day after day, month after month, year after year, Sabbath-days and week-days, have those evils to be continually taken in hand, and made the means whereby he attains his object; for though he may become so accustomed to them through daily and hourly contact as not to recognise them as such, still such they are: glass-houses, heating apparatuses, and all the other artificial appliances by which successful results are arrived at, would be much better done without, if such or any results could possibly be gained without them. It very often happens, however, that an evil, necessary to a certain extent, is carried to an entirely needless and sometimes injurious degree; the subject of this paper is a case in point. It is a fact known to everybody floriculturally biassed - excepting, perhaps, those old women (some of them keen plant-growers too) who cultivate Geraniums in spoutless tea-pots, and Fuchsias in flower-pots, the drainage-holes of which have been most innocently corked up - that efficient drainage is a most important essential in the successful cultivation of pot-plants; in fact, numbers fail with plants which stand without repotting for any considerable time through neglecting sufficiently to secure the compost in which the plant is growing from penetrating to and getting mixed up with the drainage, so laying the foundation to a sodden, soured mass, which in time results in death to every root of the plant, and, as a matter of course, the plant itself.
However, this is not the part of the subject we wish to write about, but the common practice of draining all sorts of plants after the same fashion, without discrimination as to their varied requirements, giving soft-wooded plants of all kinds and for all purposes the same treatment in this respect as that given to hardwooded and species of a slow growth.
The most glaring sample of this malpractice is to be found in the treatment of those plants professionally designated "bedding stuff." The mode of procedure in favour with some is something like this: - in the beginning of autumn, Geranium cuttings are crowded together into boxes some 4 inches in depth; that efficient drainage may be secured, "crocks," nearly an inch deep, are placed along the bottom, with a layer of grassy turf or moss laid above them to keep all "square;" when early spring arrives they are "potted off "into 3-inch or 4-inch pots, as the case may be, the best part of the roots having been left amongst the drainage of the box; the pots are also filled up with crocks and moss to a depth dependent on the judgment of the cultivator. Before bedding-out time comes round, they are completely pot-bound, and the pulling away of the drainage when they are planted out does anything but give the plants a chance of taking kindly to their new quarters without being checked. If, instead of all this unnecessary drainage, one crock had been placed over each hole in the box, a very small percentage of roots would have been lost when potting them off in spring, and very little or no forcing required to start them into growth; then a little of the roughest of the compost placed in the bottom of the pot would amply secure the requisite drainage, the plants would have more soil to work in, and at bedding-out time not a root need be disturbed in planting them: in addition to all this, at the lowest calculation, two men could do as much as three in potting, besides the time saved in simply turning the plant out of its pot, and inserting it in its place when planting out.
In the case of Verbenas, Lobelias, Ageratums, and others, which are generally grown in boxes, the same system of placing one "crock" over each hole does equally well, and the advantage they have when taken out with as good a ball as possible is most decided; where so many crocks are used, it is impossible to take the plants out without leaving the crocks full of fine roots, whereas in the other case but few roots need be lost. In the case of stove and greenhouse plants, and others which grow quickly, and require repotting in but a little time, it is altogether unnecessary to make use of many crocks for drainage. We find that in 3-inch pots, used for cuttings or seedlings, a bit of turf answers better than anything, except in the case of gross feeders such as the Tomato, Cucumber, or Strawberry, when some rough dung does best; pieces of turf do well for draining fast-growing "subjects" in 4-inch pots, such as the two first mentioned or the Chrysanthemum, but it is quite as well to place a bit of broken pot at bottom, then some roughish material for species like the Chinese Primrose or the Calceolaria. A like drainage is sufficient for sizes up to twenty-eights inclusive, but if the plants are intended to flower in those sizes, it will be quite as safe to add half-a-dozen pieces of potsherds as well.
We have made one large oyster-shell and some grassy turf do as drainage for sixteens, but it was altogether an exceptional case, and not to be advised as a rule; it so happened that some vigorous-growing young Vines in twenty-eights could not be repotted when they ought to have been, and the quantity of roots they had made induced us to drain as stated, and even then they filled the pots too quickly by a good deal. We believe in taking as much care as possible of the roots of fast-growing plants when repotting, though a good many are noways particular on this point, and the mode of draining here recommended affords every chance possible for saving the roots intact. If a plant be kept growing on without a check, either from cold or heat, from improper watering, from anything in the way of repotting, or any other accidental casualty, the chances are all in favour of its being comparatively free from insect pests, and other ills which plants are heirs to, with the certainty of its being something near the "mark" as regards appearance, and everything else that constitutes a well-grown plant.
R. P. B.