While a solution of mainly water with a small amount of table sugar is good for helping plants suffering from transplant shock, it is not beneficial and is potentially harmful to apply sugar water to healthy plants. One main reason that table sugar is bad for plants is that it attracts harmful bacteria.
According to the National Gardening Association, many trees and plants suffer from transplant shock after being removed from the ground at nurseries and placed into pots for sale at garden centers. Plants that go into shock often lose up to 95 percent of their root systems. Researchers at the Bartlett Tree Research Laboratory in England were successful in reversing transplant shock in trees by combining 10 ounces of table sugar, or sucrose, with one gallon of water and pouring this solution over tree roots at a rate of 0.4 gallons per tree on a weekly basis for one month.
However, the only time this method of reversing shock should be attempted is immediately after a plant or tree has been transplanted. According to a Living Space 360 article, gardeners need to refrain from excessive use of sugar when trying this method, as the substance promotes the growth of fungi, which are likely to rot the plant's roots.