This paper proposes an Internet of Thing system architecture based on Wireless Sensor Network (WSN) for agricultural applications. The system consists of sensor nodes and a gateway, which allows a user to monitor environmental data for agriculture using a web browser. The sensor node is a microcontroller based Arduino including wireless module and connected sensors such as temperature, relative humidity, luminosity, air pressure and other sensors. A WiFi interface is deployed to exchange the environmental information from sensor nodes to the gateway running Linux. The gateway manages and transfers data to a Cloud where data were stored and visualized as graphs.