Greenhouses are controlled area environment to grow plants. In order to achieve maximum plant growth, the continuous monitoring and controlling of environmental parameters such as temperature, humidity, soil moisture, light intensity, soil pH etc. are necessary for a greenhouse system. The main aim of this project is to design a simple, low cost, Arduino based system to monitor the values of environmental parameters and that are continuously updated and controlled in order to achieve optimum plant growth and yield. DHT11 sensor, Soil Moisture sensor, LDR sensor and pH sensor are the main sensors used in this project which give the exact value of temperature, humidity, water content, light intensity and soil pH respectively. All environmental parameters are sent to android mobile phone via offline and online. A GSM (Global System for Mobile communication) modem is used to send SMS (Short Message Service) which displays the present status of the environmental parameters. The SMS is sent to the user when the sensor value exceeds a defined level. All farmers can control their greenhouses from any place by knowing the status of their greenhouse parameters at any time and they can control actuators (cooling fan, exhaust fan, water pump, artificial light and motor pump) to adjust environmental parameters by sending SMS. Ethernet is also used to send the data parameters to mobile phone which eliminates the SMS charges. All environmental parameters are sent to server through Ethernet and stored in the database. So the user can monitor and control parameters through android mobile application.