A plant growing system (1) of the present invention includes: a first light source (2) for irradiating red light to a plant； a second light source (3) for irradiating far-red light to the plant； a control part (4) that controls irradiation operations of the first light source (2) and the second light source (3)； and a time setting part (5) that sets a time zone in which the control part (4) operates the irradiation of the first light source (2) and the second light source (3). The time setting part (5) is designed such that the first light source (2) starts red light irradiation before sunset； and the second light source (3) starts far-red light irradiation after the red light irradiation.
