A system and related method for monitoring plant growth conditions is provided, comprising a plurality of detectors (7) and central detector data processing means (1103) each detector (7) being arranged to measure properties indicative of a temperature, a water content, and a nutrient content, of a plant growth substrate each detector (7) being further arranged to transmit the measured property or properties over a communications link to the central detector data processing means (1103) the central detector data processing means (1103) being arranged to store predefined irrigation data, defining a relationship between plural values for temperature, water content, pH level and/or nutrient content of the plant growth substrate and plural desired irrigation output values process the measured properties from each detector (7) to determine calculated properties of the substrate and provide an output indicative of a desired irrigation input for the growth substrate, based upon measured properties received from the detectors (7) and the predefined irrigation data. A portable detector communications device (1105) for communicating configuration data relating to the detectors (7) may be included in the system.
