The interconnection of smart objects embedded with sensors enables them to interact with the environment and among themselves, forming a Wireless Sensor and Actuator Network (WSAN). These network nodes perform acquisition, collection and analysis of data, such as temperature and soil moisture. Such data can be employed to automate the irrigation process in agriculture while decreasing water consumption, resulting in monetary and environmental benefits. The high storage and processing capabilities, the rapid elasticity and pay-per-use characteristics makes Cloud Computing an attractive solution to the large amount of data generated by the WSN. This work proposes and evaluates on a real deployment a cloud-based Wireless Sensor and Actuator Network communication system. This solution monitors and controls a set of sensors and actuators, respectively, and integrates it with information from external weather providers to assess plants water needs.