A wireless system is provided for monitoring environmental, soil, or climate conditions and controlling irrigation or climate control systems at an agricultural or landscape site. The wireless system includes a wireless sensor network including a plurality of sensor nodes for monitoring environmental, soil, or climate conditions and controlling one or more irrigation or climate control systems at the site. The wireless system also includes a server computer system located remotely from the site. The server computer system is coupled to the wireless sensor network over a communications network for receiving data from and controlling operation of the sensor nodes. The server computer system is also coupled to a device operated by an end-user over a communications network for transmitting the data to and receiving remote control commands or queries from the end-user.