A system (10, 11) for controlling plant growth conditions in a hydroponic cultivation system, wherein at least one detector (7, 1101) for measuring at least one characteristic of a plant growth substrate, first data processing means ( 9, 1103) and second data processing means (9, 12, 1107) and data storage means (1120), wherein the at least one detector (7, 1101) comprises one or more plant growth substrates. Measuring a characteristic, and transmitting a detector identifier and the measured one or more characteristics to the first data processing means via a communication link, wherein the first data processing means (9, 1103) includes a plurality of values relating to one or more of the substrate temperature, pH level, water content, nutrient content, oxygen content, and plant parameters, and a plurality of desired irrigation parameters. Predetermined irrigation data defining the relationship between is stored in memory, the measurement characteristics received from each detector are processed to obtain the processing characteristics of the substrate, and based on the processing characteristics and the predetermined irrigation data Providing an output indicative of a desired irrigation input to the growth substrate and transmitting processed data to the data storage means (1120), wherein the data storage means is configured to transmit the transmitted data The second data processing means (9, 12, 1107) receives data from the data storage means (1120), and based on the log data, the second data processing means (9, 12, 1107) Receiving a warning condition input that calculates a prediction characteristic, determines a difference between the processing characteristic of the substrate and the prediction characteristic of the substrate, and outputs an alarm based on the difference； And wherein the difference and outputs an alarm warning condition is satisfied, the system. [Selection] Figure 6水耕栽培システムにおいて植物成長条件を制御するシステム（１０、１１）であって、植物成長基質の少なくとも１つの特性を測定する少なくとも１つの検出器（７、１１０
