Protected agriculture seeks to maximize productivity by manipulating climatic factors such as temperature to create the most favorable environmental conditions for the growth of animals and plants. This study aims to (a) identify the status of middle and small-scale protected house farmers using a questionnaire survey and (b) assess the impact of an IoT-based automation system to address identified issues of middle and small-scale protected house farmers. During the survey, the farmers revealed their inability to leave the polytunnel for at least one day without supervision and the higher labour cost as issues related to crop management. Decreased fruit quality and increased mite attacks, inability to achieve optimum crop yield were the main issues discovered which reduces the crop yield. The experiment was carried out in two protected houses where one house is under an IoT-based micro-climate controlling system and the conventional management in the other. Digital Temperature & Humidity Sensors (DHT21) were used to monitor relative humidity (RH) and temperature, and foggers and exhaust fans were used to control RH and temperature. Capacitance sensors were used to monitor substrate moisture, and a drip irrigation system was used to control it. Salad cucumber plants were grown in grow bags in each protected house. The inside day temperature was reduced by 1.55°C to 4.42°C in the IoT-based protected house and optimum inside day RH conditions were maintained. The maintained micro-climatic conditions showed a positive effect on yield and growth parameters of salad cucumber grown in IoT based protected house. In comparison to a conventional house, the IoT-based protected house had a 41.6% yield increment per vine.