Abstract: A method is disclosed herein for promoting the root growth of a plant. The method includes contacting the plant, or a seed of the plant, with a composition containing forchlorfenuron (CPPU) before the reproductive growth stage of the plant, such that either the root length of the plant is at least about 5% greater than for an untreated plant, or the ratio of root length to stem length is increased by at least 5% compared to the untreated plant.