Vegetable grafting is a horticultural technique that combines two living plant parts, resulting in one plant. The bottom portion, (rootstock), offers support and roots. The upper part (scion) is the fruit-producing section, which contributes to the plant's leaves, stems, fruits and flowers, according to Ohio State University. The scion is sliced onto the rootstock of another cultivator. The technique is a common practice, especially in Japan, where almost 95 percent of the country's melons, tomatoes, greenhouse cucumbers and eggplants are grafted, notes Ohio State University.
Vegetable grafting reduces soil-borne pests and diseases such as Fusarium wilt in cucumbers and melons. It helps protect tomatoes and peppers from bacterial wilt, notes the Food and Fertilizer Technology Center website. Grafting improves plant produce and increases soil utilization, says Wisconsin State University. It also provides additional strength to plants undergoing various types of environmental stress.
The three main methods are tongue, cleft and tube grafting. Tongue grafting has the highest success rate and is used on melons and cucumbers, notes the University of Connecticut. Tomatoes are mostly grafted using cleft grafting. In cleft grafting, rootstock seeds are sown about five to seven days before scion seeds.
Tube grafting is the fastest and easiest method, because it involves only one straight cut on the shoot and root portions. This method is useful on small seedlings as there are fewer intricate cuts.
Grafting should be done in a shady area protected from wind so grafted plants won't wilt. Expose the rootstock and scion to sunshine for two to three days before beginning the process. Do not water plants to prevent spindly growth. Ensure the rootstock and scion have stems with similar diameters, cautions the Food and Fertilizer and Technology Center.
Although grafting has benefits, some problems are linked with it. For example, it's expensive. Other problems include graft incompatibility, which can cause physiological problems, resulting in less produce, fruit quality and defective flowering formation, notes the ACTA Horticulture website. Carefully weigh the benefits and risks before increasing the amount of grafted plants.
Although vegetable grafting dates back to the 17th century, it wasn't used commercially until the 20th century in Asia. According to ACTA Horticulture website, eggplants were the first vegetables to be grafted in the 1950s. Next tomatoes and cucumbers were grafted from 1960 to 1970. In Japan and Korea, 700 million grafted vegetable plants were grafted in 2000. The technique is mostly used in North America to increase greenhouse tomato yields.