The root is a highly adaptive organ providing physical support and capacity to take up and store water and nutrients. In vascular plants, the root system, with a primary root and lateral roots, mainly originates and develops from embryonic tissue. Adventitious roots on the contrary have distinct functions and emerge post-embryonically. Adventitious root formation is strongly enhanced by exogenous application of auxin, yet for many crops exposure to light inhibits rooting and a dark incubation is required for it to be successful. Despite the economic importance of root induction in cuttings, little is known about light regulation of adventitious root formation. Here we set out to discover molecular signaling components that underlay light control of adventitious root induction. With our discovery of an auxin-like compound that massively induces hypocotyl adventitious root formation in a light dependent fashion, we are encouraged to find regulators that are responsible for the suppression of rooting in the light. The results are pivotal to further our insight into the function of adventitious rooting and to develop tools that improve the rooting of shoots which is a vital component of many clonally propagated crops.