Technologies of irrigation systems are developed with a focus on intelligent water management, advanced features and remote control of solar photovoltaic watering systems (SPVWSs). The new generation of inexpensive microcontrollers comes with high level of computation capability and provides low-cost solutions. In this direction, this paper presents a new multithreading design and implementation of an embedded irrigation system running on solar power. The design combines the advanced concepts of concurrency programming, namely multithreading and virtual timers, with the embedded computing resources of smart devices. According to the design and test results through an experimental greenhouse, this device provides an accuracy real-time management of all activities of the SPVWS with eventually a low power consumption.