Grafting is the process by which a branch from one established citrus tree (bud stick) is joined to the branch of another established citrus tree. Branches are surgically combined to produce a new shoot and eventually different citrus fruit on the same tree. Grafting plants ensures healthy and successful harvests at a much sooner time. Citrus trees with multiple fruit growing from them are known as "cocktail trees."
Select the bud sticks that will be used. Optimal bud sticks are roughly 1 year old and 1/4 inch or less in diameter. If grafting cannot be done immediately, the bud sticks can be wrapped in wet paper towels and stored in the refrigerator for up to three weeks.
Determine the location for grafting. The best branches to use are those that are 1/2 to 3/4 inch in diameter. Avoid placing the new bud stick in an area that will be receive south or west sun exposure, as it can become sunburned. Verify that the tree's bark is slipping before beginning the grafting process.
Sharpen the grafting knife. Grafting knives are a one-sided bladed knife that must be razor sharp for proper grafting. To test the blade, carefully shave some arm hair. If the hair comes off easily, the blade is sharp enough. If not, consider having the blade professionally sharpened before grafting.
Using the sharpened grafting knife, make a vertical cut approximately 1 1/2 inch in length and deep enough to cut into the wood. Make a horizontal cut underneath the vertical cut 1/2 inch long. When finished, it should appear as an inverted "T."
Create a bud stick. According to John Begeman, Professor at the University Of Arizona Department of Horticulture, bud sticks are created by "selecting a plump dormant bud, located at the point directly above where a leaf petiole attaches on the stem. Make a horizontal cut across the bud stick about one-half to three-quarters inch above the bud. Cut the bud and a small piece of wood underneath it using a continuous motion. The cut should begin about one-half to three-quarters inch below the bud, and should end at the horizontal cut made above the bud. Lift the chip of wood containing the bud, using the leaf petiole (leaf removed) as a handle. This will avoid contaminating the cut side of the bud chip with soaps or oils from your fingers."
Carefully peel back the bark from the "T" cut and slide the chip inside. Push the bud chip down from the top of the "T" toward the bottom until the bark firmly holds the new bud in place. Position the bud so that it will grow in the same direction as the branch.
Tightly wrap the graft with budding tape. The wrap should be stretched so tightly that it is almost to the point of tearing while wrapping the plant. Continue wrapping until the two are firmly attached to one another. Wrap the graft so that only the bud and leaf petiole are peeking out. This will ensure that the graft remains moist enough for proper healing to take place.
Remove the wrap after a few weeks. If the graft was successful, the bud will have turned into a new shoot.