If you’ve never tried to graft a plant, you may be surprised at the technique’s simplicity. Although some grafting methods are more appropriate for experienced gardeners, but simple grafts are within reach of the average gardener. So if you have a steady hand, some sterile tools and a little patience, you can master the grafting basics.
One of the most important steps in grafting a plant begins before you make any cuts. If your hands or the cutting tools are dirty, you can transmit a disease to a grafted plant. Dirty hands and tools may harbor pathogenic bacteria that spread to the cut surfaces of the plants and invade a plant systemically. Wear latex gloves after you wash your hands with anti-microbial soap, and sanitize your cutting tools. Although sterilized tools may not stop disease transmission, they may reduce the chance of infecting plants. Dr. S.A. Miller of Ohio State University recommends dipping the grafting blade in alcohol, passing it through a flame, and allowing the tool to cool before making any cuts. This is called "flaming."
Two of the simplest grafting methods depend on what kind of plant you’re grafting. For small seedlings, such as tomato (Lycopersicon esculentum) -- a tender perennial in U.S. Department of Agriculture plant hardiness zones 10 through 11 -- splice grafting, also known as slant-cut grafting, is typically used. Splice grafting is the most common technique to graft an heirloom tomato scion onto a hybrid tomato stock. Whip grafts are suitable for young woody plants with tender stems that are 1/4 inch to 1/2 inch in diameter.
Using a flamed blade, sever the stem of one plant -- called the scion -- to graft onto the severed rootstock -- called the stock -- of another plant. To make a splice graft, cut a scion from one plant and the stock of another plant that has a similar diameter at 45-degree angles. Match the scion to the stock and use a silicone grafting clip to hold the two parts together. As the new plant knits together, the grafting clip will fall away. Preparing a plant for a whip graft, also called a tongue graft, starts with making a 2 1/2-inch cut angled upward on the scion and a similar cut on the stock, angled downward. Make a downward cut through the middle of the stock’s new slanted surface and an upward cut through the middle of the scion’s new slanted surface. Fit the two pieces together until they interlock like jigsaw puzzle pieces.
A silicone grafting clip is all you need to join a splice-grafted plant as it knits together. But whip grafts need a slightly firmer method to hold the two plant pieces together until the graft sets. Otherwise, the cut pieces can dry out, preventing a successful graft. You can use hand wax, which you soften in your hands, or brush wax, which you apply with a brush after heating it. Apply the wax so it covers all the cut surfaces of the graft, making sure that you don’t dislodge the interlocked stock and scion. Although you can purchase grafting tape, you can also use masking tape for whip grafts. Wrap the tape around the waxed area so it fits snugly but not so tightly that it cuts into the stems. You can safely remove the tape when new growth forms.
- North Carolina State University Cooperative Extension: Grafting for Disease Resistance in Heirloom Tomatoes
- Missouri Botanical Garden: Lycopersicon Esculentum
- Missouri Botanical Garden: Persea Americana
- University of California Cooperative Extension Agriculture and Natural Resources Ventura County: Answers to Frequently Asked Questions About Avocados
- Arizona Cooperative Extension: Plant Propagation -- Asexual Propagation
- Washington State University Extension: Vegetable Grafting -- Eggplants and Tomatoes
- University of Missouri Extension: Grafting
- The Ohio State University Extension: Grafting Guide