This section is from the book "The Gardener V2", 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.
So extended has now become the cultivation of window plants, either as grown within the glass in pots, or without the window in boxes, that attempts in this direction can be seen on every hand by any one who may take a casual walk through any district of London; and numerous illustrations are furnished, from the window jardinet of the aristocratic mansion in Grosvenor Square, down to the creeping jenny or some such humble floral ministrant that occupies the sill of the second and third floor windows of a dingy-looking house in a narrow street of the Seven Dials. In this way, "one touch of nature" does indeed "make the whole world akin," for the same love for flowers creates the effect in both cases. I always link with the appearance of flowers in the windows of a densely populated neighbourhood the presence within the house of some aspect of the better nature in human kind, that finds its expression in the loving, tender care bestowed on some poor stunted plant or plants, which goes far to redeem humanity from that wholesale demoralisation it is the fashion of some to be continually charging against it.
It is interesting to know that in many of the districts of London there is a growing desire to encourage exhibitions of window plants among the labouring classes as well as among the elder children of the parochial schools. A very small subscription list serves to create a number of prizes, for which there is often very keen competition; and a schoolroom can always be made available for the purposes of the show. The value of these exhibitions, in a civilising and elevating point of view, cannot be too highly estimated, for it has been abundantly manifested that the simple tending of a few homely plants, and the feelings inspired by such an act, are invaluable in counteracting influences of a debasing character; and have been made instrumental in elevating the home life of a family beyond the ordinary low levels of many a London dwelling.
Some of the best and most easy of culture among window plants are the common Hydrangea, Fuchsia, the Zonale or horseshoe-leaved, as well as the plain-leaved, the variegated, large-flowering, and scented-foliaged Geraniums (though it is now considered to be scientifically inaccurate to term these Geraniums, as they are properly Pelargoniums); the Mesembryanthemum, or Fig Marigold; the well-known Calla AEthiopica; the Balsam, the Indiarubber plant (Ficus elasticus); the Myrtle, Petunia, Heliotrope; the old crimson China Rose; some easily-grown varieties of the Cactus; the yellow-flowering Cytisus race-mosus; some of the hardy Ferns, etc, - while even simple flowers, such as the Musk, Auricula, Polyanthus, Cowslip, Double-Daisies, Heartsease, and others, can be added. The foregoing list comprises nothing but what can be obtained of any dealer in plants at a very moderate, if not even a cheap, rate.
Now, no one can expect to grow plants to perfection, or, failing this, to attain anything like moderate success, unless some care and attention are bestowed upon them. Where there is a love for plants, this necessary service is cheerfully and willingly rendered.
A few simple rule3 may prove very acceptable to many who are cultivating window plants in pots. 1st, It is highly necessary that, at the outset, the plants be young and healthy. Diseased and debilitated plants will bring disappointment, and the labour expended on their culture will be, to a great extent, labour lost. 2d, Plants should be properly potted - that is to say, good soil should be used - something that will supply the plant with the necessary food for its sustenance: there should also be ample drainage - pieces of broken flower-pots are used for this purpose - and the plants should, as a rule, be firmly potted - that is, the soil should be firmly pressed about the roots. 3d, The plants should never be allowed to get dry; and, on the other hand, the soil should not be drenched too heavily. It is always best that the water given to the plants be allowed to pass freely from the bottom of the pots, and thus, to keep water standing in the saucers occupied by the plants is generally a bad practice, as it will often so sodden the roots that they will rot, and the plant become unhealthy, if it does not die outright: and 4th, Air must circulate freely among the plants if they are to be made healthy and to thrive well; therefore sash-windows are always best for flowers, as a supply of air invariably finds its way in from without, even when the sashes are closed.
Plenty of light is as indispensable as plenty of air, and the undue crowding of the plants should be altogether avoided. Window-gardeners are often what may be termed "greedy" in this respect; they so crowd their windows that the inevitable result is, the plants are all badly done, whereas a few could be managed with the best possible results. The cultivation of window plants is always open to one annoyance, that of the presence on the plants of a small green insect, generally denominated the "green-fly." When these appear, some soap-and-water should be applied, either by the use of a soft brush or by the hand, carefully washing off the fly in the act.
As window plants are generally very much exposed to the sunshine, the action of the sun will produce flagging, loss of leaves, and a decay of health if the plants are not well supplied with water. The moisture supplied to the plants must be regulated by the weather; but I have met with some window-gardeners who evidently thought, judging from their practice, that no more water was needed during a hot day in July, than in a dull close misty day in November'. The old antipathy to watering plants when the sun is on them should be got rid of. If the plants can be sprinkled overhead in hot weather, so much the better; it helps to impart vigour to the plants, as well as to keep them clean. In dull wet weather it need not be done, but the leaves can be kept occasionally cleansed by using a piece of damp sponge.
These are very simple rules that can be carried out at odds and ends of time; their performance involves no labour, scarcely any expense, and but little time in the aggregate. The pleasure enjoyed as per contra who can estimate it 1 Depend upon it, plant-growing is the operation of a no mean home-influence for good, and it is one of the aims of the 'Gardener' to extend this influence as far as it can lend a helping hand to do so.