Vegetable production using grafted seedlings began in Japan and Korea as a way to avoid serious crop losses due to soil-borne diseases that are exacerbated by continuous cropping.
What crops should be grafted under CEA and why?
Grapes, of course, are well known as grafted crops, as are apples and other stone fruits. They have been grafted for centuries to avoid similar problems caused by soil-borne diseases. It’s taken us a while to catch up, but with every area of CEA being scrutinized for greater efficiency, it’s no wonder grafting is becoming the industry standard. Tomatoes are the latest crop to benefit from grafting onto stronger rootstocks to prevent disease and increase yields.
The tomato in the picture above is from a grafted plant. It looks just like any other tomato, right? But what makes it different is that the farmer who grows this tomato doesn’t have to go through the heartache and stress of having a diseased crop.
Grafting has been popular in Asian countries for decades and is now used successfully with many hydroponic crops, including watermelon, cucumber, tomato, pepper, pumpkin, and eggplant.
Currently, more than 90 percent of watermelons are grafted onto pumpkin rootstocks to avoid Fusarium wilt, according to Dr. Chieri Kubota, professor at Ohio State University and director of the OHCEAC.
Grafting also minimises the absorption of undesirable pesticide residues and allows grafted plants to adapt more easily to lower soil temperatures and higher soil salinity, especially in conservation cultivation where successional or continuous farming is commonplace.
Maximize efficiency for profit
To be profitable, VFs must utilize all available technologies to maximize yields and profits. Grafting is a labor-intensive technique, but many VFs have started to automate the grafting process. Improving the quality and availability of plug-grown grafted seedlings will further contribute to the increased use of grafted vegetables in the CEA and help farmers have more choices in soil mixes and substrates. Optimizing conditions for long-distance transportation of grafted plants is a key factor to prevent quality loss on the way to farmers.
Automation of tomato grafting at Green Tech this year.
Grafting has become increasingly popular as companies compete for retail sales, and scaling up in large greenhouses requires automation. The graft itself consists of a high-quality scion grafted onto a hardy rootstock that is resistant to common tomato diseases. The junction must be above the soil or rockwool, otherwise the rootstock will stretch. Popular tomato rootstocks include Maxifort and Estimiino, which are more likely to overcome pH changes, water shortages, and temperature fluctuations, and to absorb nutrients more efficiently.
Dr Janet Colston is a pharmacologist interested in growing “functional” foods that contain additional phytonutrients beneficial to human health and exhibit medicinal properties. She grows these foods using a variety of techniques, including micropropagation of plant tissues and controlled environment agriculture, to ensure the highest quality control.
