This section is from the book "Commercial Gardening Vol1", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Unlike budding, where a single bud is used, grafting consists in affixing a shoot of one plant with two or more buds on to the stem of another in such a way that the cambium layer of one must come face to face with that of the other. The shoot is called the "scion", and the plant on which it is placed is called the "stock" - the latter being already well rooted and established for twelve or eighteen months in advance to ensure complete success. As in budding, so with grafting - the stock and scion must be closely related, and belong at least to the same natural family. There are several ways in which grafting may be done, and the principal ones will be mentioned.
Fig. 74. - Showing Stock A, with ┬-cut at a for reception of Bud B, side view of which is given at e, and inner face view at d.
This is the best method when the stock and scion (or graft) are nearly of the same thickness, and thousands of fruit trees are propagated in this way every March and April in the open air. Preparatory to grafting taking place the stock is usually "headed" back in January or February; that is, the stem is cut off, leaving a stump a few inches high sticking out of the ground. The cut surface soon heals, as little or no sap is rising at that cold period of the year. The grafts or scions, which always consist of ripened one-year-old shoots, are also severed about the end of January or February, and are "heeled in" in bundles under a north wall. This prevents them starting into growth prematurely, and keeps the sap in them in a less active condition than if the shoots were allowed to remain on the parent plant.
The grafting period in the open air being reached, that is, in March and April, a slanting cut is made in the stock as shown in fig. 75, and a nick is made in it to form a tongue. The graft or scion, having two or three buds attached, is also cut obliquely, as shown in the figure, and a tongue is also made in it so that it shall fit into the one made in the stock. The two cut surfaces should be about the same length and width if possible, but it is not essential. One edge of the scion, however, must be made to fit flush with the edge of the stock, to bring the cambium layer of each face to face, because it is by means of the new cells from the cambium that union is to take place. The graft being properly fitted to the stock it is then tied round securely with raffia, or matting, or worsted thread, after which the joint is covered over completely with grafting wax, or clay made into "pug" by mixing it with a little chopped hay or straw. A good grafting wax may be made by boiling in a saucepan some beeswax, resin, and Russian tallow in equal proportions. While still warm (not hot) this mixture, which should be of the consistence of treacle, is easily applied with a little brush or flat piece of wood. A rough-and-ready method of grafting as practised in some market gardens is shown in fig. 76, taken from an actual specimen.
Fig. 75. - A Graft or Scion A, cut and tongued at T to fit top of Stock B; at c is shown the Graft and Stock united, tied, and waxed or clayed.
Fig. 76. - Showing how Badly Treated Young Fruit Trees are grafted in some Market Gardens.