Design and evaluation of an automatic control system for hydroponics cultivation of mint

Hydroponics is emerging as a beneficial technique to augment food production in which the quality and yield of a crop are improved by accurately maintaining the desired electrical conductivity (EC), pH and dissolved oxygen (DO) in the nutrient solution. This article describes the development of an automatic control system for mint cultivation in hydroponics that consists of EC, pH, and DO sensors which continuously monitor the respective parameters and control their value in nutrient solution with the help of microcontroller and actuators. The developed system maintained the EC, pH and DO of the nutrient solution within their desi­red limits of 2.0–2.5 dS m^–1, 6.0–6.5 and above 8 ppm respectively. The plant height, average leaf area per plant and total chlorophyll content of the mint plants varied between 18.9–20.3 cm, 15.69–18.45 cm² and 23–30 (SPAD units) respectively. The results of this study emphasize the system’s effectiveness in monitoring and controlling the parameters of the nutrient solution thereby maintaining favourable growth conditions in the hydroponic cultivation of mint.