PROBLEM TO BE SOLVED: To provide a watering control system capable of executing watering at a proper timing.SOLUTION: A watering control system comprises: imaging parts Ca1, Ca4 for imaging a leaf of a cultured plant; a tension index value calculation part 43 for calculating a tension index value which indicates a tension index of a leaf on the basis of photographed images acquired by the imaging parts Ca1, Ca4; a standard calculation part 42 for calculating a watering standard value on the basis of the tension index value in a standart time; and a watering instruction part 46 for outputting a watering instruction signal when the tension index value becomes lower than a watering standard value.SELECTED DRAWING: Figure 5COPYRIGHT: (C)2020,JPO&INPIT【課題】適切なタイミングで灌水を実行させることが可能な灌水制御システムを提供する。【解決手段】栽培植物の葉を撮像する撮像部Ca1、Ca4と、撮像部Ca1、Ca4により取得された撮像画像に基づいて、葉の張り度合いを示す値である張り指標値を算出する張り指標値算出部43と、基準時における張り指標値に基づいて灌水基準値を算出する基準算出部42と、張り指標値が灌水基準値を下回った場合に灌水指示信号を出力する灌水指示部46と、を備える。【選択図】図5