The economic importance of agricultural grains makes it imperative to constantly monitor the conditions of the stored grains for timely response to possible deterioration in real time. Most various measures previously adopted were observed to be deficient in steadiness of real-time monitoring and automatic control operability. This paper presents the use of a wireless sensor network to monitor in real-time the variation in temperature, humidity and light illumination parameters affecting stored agricultural grains and automatically initializing control measure for the effect whenever necessary. This work used adequately characterized sensing devices, intelligent XBee transceiver, well-selected and modified Arduino platforms, modified mesh topology and four-relay port module to implement the end nodes and the coordinating hub. The end node characterization achieved a good agreement with the reference study and the accuracy of the real-time monitoring of the system was above 96%. It is concluded that it is feasible to achieve the real-time monitoring and automated control of environmental factors in granary system using wireless sensor network.