PROBLEM TO BE SOLVED: To provide an illumination system for plant growth that efficiently irradiates a plant with light and promotes the growth of the plant at low power consumption.SOLUTION: An illumination system for plant growth according to the present invention has a humidity detection part (40) installed in the environment in which a plant (11) is grown, an illumination part (20) irradiates the plant with light, and a control part (30) that controls the illumination part (20). The control part (30) controls light irradiation operation of the illumination part (20) according to a relative humidity detected by the humidity detection part (40) within a predetermined time.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2016,JPO&INPIT【課題】 植物に効率的に光を照射して、低消費電力で植物の成長を促進させる植物育成用照明システムを提供する。【解決手段】 本発明の植物育成用照明システムは、植物(11)の育成環境に設置された湿度検出部(40)と、植物に光照射する照明部(20)と、照明部(20)を制御する制御部(30)とを備え、制御部(30)は、所定の時間内に湿度検出部(40)で検出された相対湿度に応じて照明部(20)の光照射を制御することを特徴とする。【選択図】 図1