Apple tree cuttings planted in the ground will not grow into fruit-producing trees. For the best results, they should be grafted onto an older rootstock, which will provide protection and resistance against soil-borne pathogens like those that cause oak-root rot, stem and crown rots, wilt diseases and crown gall. Most apple rootstock are dwarf varieties, since apple trees can grow up to 30 feet tall, an impractical size for most home gardens. Grafting cuttings from an old, failing tree onto younger rootstock will keep its apples in your life for years to come.
Choose the root branch. Cleft grafting works best on a rootstock branch 2.5 to 5 cm (1 to 2 inches) in diameter. Choose a branch not more than 1 to 1.8 metre (4 to 6 feet) off the ground to keep the fruit at a level convenient for picking.
Cut off the root branch to leave a 5 to 7.5 cm (2- to 3-inch) stump. This reduces the likelihood of the tree putting out competing branches that will have to be pruned later.
Split the stump down the middle, taking care not to strip away any bark. To this end, use a fine-toothed saw for thicker branches.
Use two cuttings (scions), each with at least three buds. They should be 0.6 to 1.25 cm (a quarter- to a half-inch) in diameter.
Whittle the ends of both scions so they slope inward.
Hold the slit open with a flathead screwdriver and insert one scion on one side of the slit and one on the other. Tilt the scions very slightly outward so the barks are not flush with each other.
Waterproof the union by applying grafting compound to cover the full length of the cleft.
Prune old trees for a season or two before attempting to graft young scions onto them. This way you will have more small, young branches on which to graft stock.