Читать книгу Gardening Indoors and Under Glass - F. F. Rockwell - Страница 21

While many plants are best started from seed, as described in the preceding chapter, there are many which cannot be so reproduced; especially named varieties which will not come true from seeds, but revert to older and inferior types.

Also it very frequently happens that one has a choice plant of some sort of which the seed is not to be obtained, and in this case also it becomes necessary to reproduce the plant in some other way.

Where large numbers of plants are to be started, and they may be had from seed, that is usually the best way in which to work up a supply: but where only a few are wanted, as for house plants or use in a small garden, propagation by cuttings is the quickest and most satisfactory method. Practically all of the house plants, including most of those which can be started from seed, may be increased in this way.

The matter of first importance, when starting plants by this system, is to have strong, healthy cuttings of the right degree of hardiness. Take your cuttings only from plants that are in full vigor, and growing strongly. They should be taken from what is termed "new growth," that is the terminal portions of shoots, which have not yet become old and hard. The proper condition of the wood may be determined by the following test: if the stem is bent between the fingers it should snap (like a green bean); if it bends and doubles without breaking it is either too old and will not readily root, or too soft and will be almost sure to wilt or rot.

The cutting should be from two to four inches long, according to the plant and variety to be propagated. It should be cut off slant-wise, as this will assist in its being pushed firmly down into the cutting box. It may be cut either near, or between a joint or eye—with the exception of a few plants, noted later. The lower leaves should be taken off clean; those remaining, if large, shortened back, as shown in the illustration facing page 29. Then the plant will not be so likely to wilt.

If the cuttings cannot be put in the propagating medium immediately after being made; keep them in the shade, and if necessary sprinkle to prevent wilting. I once obtained a batch of chrysanthemum cuttings from a brother florist who said that they were so badly wilted that they could never be rooted. I immersed them all in water for several hours, which revived them, and had the satisfaction of rooting almost every one.

The medium most commonly used in which to root cuttings is clean, medium-coarse sand, such as builders use. It must not be so fine as to pack tightly, nor so coarse as to fit loosely about the cuttings, and admit air so freely as to dry them out.

Make a flat similar to that used for starting seeds, but four or five inches deep. Place in the bottom an inch or two of gravel or coal ashes, covered lightly with moss or a single thickness of old bag, and then fill nearly full of clean sand. Make this level, and give a thorough soaking. After drying out for an hour or so, it is ready for the cuttings.

Mark the box off in straight lines, two or three inches apart, and insert the cuttings as closely as possible without touching, and to a depth of about one-third or one-half their length. A small, pointed stick, or dibber, will be convenient in getting them in firmly. Wet them down to pack the sand closely around them.

The best temperature for the room in which the cutting box is to be kept will be from fifty to fifty-five degrees at night. Like the seed box, however, it will be greatly helped by ten or fifteen degrees of bottom heat in addition. For method of giving this extra bottom heat, see page 26.

If the box is kept in a bright sunny place, shade the cuttings with a piece of newspaper during the heat of the day, to prevent wilting, and if the weather is so hot that the room is warmer than seventy degrees, an occasional light sprinkling will help to keep them fresh.

Never let the sand dry out or all your work will be lost. As a rule, it will require a thorough soaking every morning.

With these precautions taken, the cuttings should begin to throw out roots in from eight to twenty days, according to conditions and varieties. Do not let them stay in the sand after the roots form; it is much better to pot them off at once, before the roots get more than half an inch long. If some of the cuttings have not rooted but show a granulated condition where they were cut, they will be safe to pot off, as they will, as a rule, root in the soil.

The above method is the one usually employed. There is another, however, just as easy and more certain in results, especially where bottom heat cannot easily be had. It is called the "saucer" system of propagation. Make the cuttings as described above. Put the sand in a deep, water-tight dish, such as a glazed earthenware dish or a deep soup plate, and pack the cuttings in as thickly as necessary. Wet the sand to the consistency of mud and keep the dish in a warm light place. The temperature may be higher than when using the sand box, and there will not be a necessity for shading. The sand must be kept constantly saturated: that is the whole secret of success with this method of rooting cuttings. Pot them off as soon as the roots begin to grow.

Cuttings made by the two systems described above are usually taken in autumn, or in spring. When it is necessary to get new plants during June, July or August, a method called "layering in the air" will have to be resorted to if you would be certain of results. Instead of taking the cutting clean off, cut it nearly through; the smallest shred of wood and bark will keep it from wilting, but it should be kept upright, for if it hangs down the end of the shoot will immediately begin to turn up, making a U-shaped cutting. The cuttings are left thus partly attached for about eight days or until they are thoroughly calloused, when they are taken off and potted, like rooted cuttings, but giving a little more sand in the soil and not quite so much water. They are, of course, shaded for several days.

Some of the plants ordinarily grown in the house, such as Rex begonias, rubber plants, sword ferns, are best increased by leaf cuttings, topping, layering or other methods differing from seed sowing or rooting cuttings. These several operations will be described in treating of the plants for which they are used.

Having carried our little plants safely through the first stage of their growth, it is necessary that we use some care in getting them established as individuals, and give them the best possible preparation for successful service in their not unimportant world.