A wireless system is provided for monitoring environmental, soil, or climate conditions and/or controlling irrigation or climate control systems at an agricultural or landscape site. In some embodiments, the wireless system includes at least one wireless nodes for monitoring environmental, soil, or climate conditions and/or for 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 node/s over a communications network for receiving data from and controlling operation of the node/s. 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.