At that time nearly everything was placed in pots of almost pure white sand, surrounded by the ordinary atmosphere of the house; while nowadays the establishment must be small indeed if it does not contain some place where the bed is so arranged that the heat at the bottom is from ten to fifteen degrees above that of the house proper. Here lies the whole secret as to whether it is a part of a single green-house or a house devoted exclusively to propagating purposes. For the purpose of being able at all times to control the temperature of the top, the propagating house has often a northern exposure, except in the very dead of winter. With a bright, clear sun above it is almost impossible in the daytime to keep down the temperature of the house sufficiently to prevent the young cuttings from wilting, after which disaster is very likely to follow in their final rooting. Given a top temperature never above 55 or 65 degrees, with a bottom always from 10 to 15 degrees higher, if the cuttings are in good shape it is a simple matter to root them in from seven to fifteen days; though the time it takes depends, of course, upon the plant and condition of the wood. At first efforts used to be contrived to get this bottom heat by means of the old flue system, with plenty of material covering the bricks, to break, in part, the dry burning nature of the heat.
Then hot water came in and furnished what was thought the acme of a propagator, and tanks of elaborate workmanship, and made of the finest material down to the commonest wood, were made so a circulation of hot water was kept up over as large an area as the necessity of the owner might require.
The results seemed excellent, but lo, every now and again, disastrous failures would occur. A material would spread all around called by the florist the cutting bench fungus, that would sweep through his crop like a plague; all sorts of theories would be given, and numberless articles appear in the horticultural periodicals of the day on its cause and cure. Presently it was found that those who did not use a tank of water, but had inclosed a space to be heated by hot water pipes, did not seem to suffer so much from the invidious foe. Much moisture was found an excellent remedy for the enemy, though it might have been its first cause, as it could be best warded off by dousing with the once praised hot water tank.
Whether a house is used exclusively or not, the ordinary hot water pipes are simply inclosed in a brick or wood space, with ventilators that may be opened to let off part of the confined heat into the house at pleasure. The front benches used are about two feet six inches to three feet in width, over, say four 4-inch pipes, up to within eighteen inches or two feet of the glass. On this is a platform over which three to six inches of sand is put, and in this bed are placed the cuttings where, with the differences before mentioned, they are kept as uniform as possible, and the sand kept decidedly wet. Almost everything we called soft wooded, or that can be got from the soft wood, even including most of our hardy shrubs, can be rooted with almost unerring certainty in the larger establishments by the hundreds of thousands.
As modern ideas demand large propagating, even in the summer, when it is next to impossible to keep these proportions of top and bottom heat, if in an ordinary propagating house, such firms as Miller & Hunt, strike out with another idea to overcome the difficulty. This is none other than instead of glass, they have a muslin canvas-covered house, in which they have again pits, where mild bottom heat can be obtained by the use of spent hops, tan bark, manure, or other material. Of course, it would be idle to talk of a summer bottom heat of 60 deg., but instead of that, they get one of about 80 deg., and depend upon a close, uniform, high, moist temperature to carry out the same results.
With this, rose plants can be and are raised by the hundreds of thousands from the single eye to a cutting, with a loss of not five per cent in the aggregate, and often not one per cent. It is very evident that with new or scarce plants this is an enormous average, as by its means firms can import the new European plants in the spring, at perhaps very high rates, start them into immediate, rapid growth, and from half a dozen plants to work on, maybe in the next spring markets have hundreds for sale.
This is all new as managed by us old 'uns in former times, but he who expects to be up with the present day and cater for that class of patronage, must take the new and not the old way of doing things, or he will, in the vernacular of the streets, "get left."
As we are on this particular topic, however, and as the amateur window plant-grower may want to propagate some little stock as well, even if not on these "high-falutin" ways, it might not be amiss to say that beyond the methods of "slipping" here and there cuttings in and among others growing in pots, or, mayhap, in a pot all by themselves, they can readily root lots of plants in a water and sand bath, which is nothing more than taking a deep saucer, putting half an inch of sand in the bottom, filling up the saucer full of water, and keeping it full; stick your cuttings into this, place right in the sunniest spot of your window, and they will grow about as certain, many of them, as if treated by the florist's more portentious method. Likely the reason of all this is, the water keeps the cuttings from wilting long enough for them to put forth their efforts for existence in the shape of new roots, obtained from the stored up material in the cuttings, and as soon as this is done they become new individual plants, requiring only to be transferred into a suitable medium of earth to go on as an independent, but similar existence to the plant from which they were obtained.
Edgar Sanders.