Low-cost open-source platform for irrigation automation

•Water-saving irrigation technologies are needed to optimize crop production.•Low-cost open-source controllers can be used to automate irrigation systems.•Real-time soil moisture measurements allow water application on demand and increase water use efficiency in cherry tomatoes. Sensor-based irrigation can be used to optimize crop production and deliver water precisely on demand. However, commercially available control systems can be expensive. To reduce the cost of automated irrigation systems, researchers have used alternative low-cost open-source platforms coupled to capacitive sensors that can monitor volumetric soil water content (VWC) in real-time, allowing on-demand water supply to plants. This study aims to design and develop a low-cost open-source irrigation system using a prototyping platform connected to soil moisture sensors to monitor and control irrigation automatically. And additionally, determine the water use efficiency of two cherry tomato (Solanum lycopersicum var. cerasiforme) cultivars grown using the system. The platform was designed, assembled, and tested to verify the ability to trigger irrigation on-demand at four different VWC thresholds at 0.23, 0.30, 0.37, and 0.44 m3 m−3. The setup used a microcontroller (Arduino Mega 2560 Rev3; Arduino, Ivrea, Italy) connected to soil moisture sensors (10HS; METER Group, Pullman, WA) and relay drivers (Adafruit; New York, NY, USA) to trigger irrigation automatically. This manuscript explains how to assemble the system using commercial equipment readily available in the market. Results indicate that the low-cost open-source platform and soil moisture sensors successfully monitored soil VWC and reliable controlled irrigation in cherry tomatoes. The technology significantly improved water use efficiency with the increase in VWC to trigger the system automatically.