Disclosed herein is a method of enhancing plant growth, comprising treating a seed at least two years prior to planting with a flavonoid, such as chalcones, anthocyanidins, coumarins, flavones, flavanols, flavonols, flavanones, isoflavones, enistein, daidzein, formononetin, naringenin, hesperetin, luteolin and apigenin wherein, upon harvesting, the plant exhibits at least one of increased plant yield measured in terms of bushels/acre, increased root number, increased root length, increased root mass, increased root volume and increased leaf area, as compared to a plant harvested from a control seed, optionally a control seed treated with the flavonoid just prior to or within a week or less of planting.
