Grafting is a process of uniting two different plants so they grow as a single plant. Most varieties of fruit trees and plants are grafted to produce healthier fruit, healthier roots or a root system better suited to a particular climate or soil conditions. Grapes are favored by people around the world, and their different varieties make delicious jams, jellies, preserves or drinks. Grape plants, however, are grafted so the vineyard produces a variety that is in demand and thus profitable, or to grow a variety that is not indigenous to a particular area.
Locate a healthy disease-free twig on a grape plant that is at least a year old and has three visible buds. This twig is known as the scion, and should be on the grape plant with the desired flavor. The ideal time to take the scion is in the winter, when the plant is dormant.
Sterilize a sharp-pointed knife in a solution of alcohol and make a sharp, diagonal cut to separate the scion twig or bud stick from the branch.
Wrap the scion in a zipper bag filled with sphagnum moss and place it in a refrigerator or a cool moist place until spring--the ideal time to graft plants because they are out of their dormancy period and chances of healing are highest.
Remove the bud stick or scion from the refrigerator in April or May. Use an upward slicing motion to separate a bud from the bud stick, along with some wood. Start 1/2 inch below the bud and slice inward, taking some bark and nutrient-dense tissue underneath before ending the cut 1/2 inch above the bud. This piece is called the bud shield.
Examine the local plant, also called the rootstock or simply stock, that you will unite the scion to. Chip a small section of its bark to determine whether it comes off easily to determine whether it is ready for grafting.
Make a vertical cut in it to separate the bark. Make a horizontal cut over the vertical cut, so it resembles a "T." If the rootstock belongs to a species of grape plants that is likely to "bleed," make a small cut just below the "T" to prevent it from bleeding in the graft itself.
Carefully slip the bark from the "T" to separate them, exposing a pocket into which you will insert the bud. Be careful you do not tear the flaps of bark.
Slip the bud shield into the flaps, ensuring the wood on it touches the wood on the rootstock. Fold the flaps back over the bud shield, while the stick pokes out.
Wrap grafting tape tightly over this union so both the pieces grow as one. Remove it after three weeks, once the union has healed. You can cut the upper portion of the rootstock to encourage the bud to grow.