Global temperatures have raised because of phenomena such as Greenhouse effect and Global warming. Theses phenomena affect primary producers; plants, on earth. As health issues become significant in Thai society, variety types of healthy food are available in Thai markets, Sunflower sprouts are sold among them. The controlled room or greenhouse became needier in plantation and seedling because air temperatures and humidity can be adjusted and controlled to suit plants inside the greenhouse, the temperatures in the greenhouse could be reduced from 2 to 10 Celsius and relative humidity could be arranged from 70 to 99%RH. This work focused on utilizing the greenhouse installed with the developed temperature and humidity controller in sunflower seedling for income earning in a community. A new temperature and humidity controller including sensors was designed and fabricated to control conditions inside the greenhouse based on Arduino technology with a low fabrication cost and easy to program as well as maintenance. The greenhouse investigation was performed by using three different sunflower seedling nutrient solutions which were affordable and locally available solutions; a commercial nutrient solution, solutions prepared from cattle and earthworm manure bio-extracts, and three different seedling materials; cotton balls, coconut coir and loam. The greenhouse was set 4 Celsius lower than ambient temperatures and temperature and different relative humidity values compared with the ambient air were set to be between 25 and 35%RH, the greenhouse performance in this work was indicated by sunflower sprout germination percentage and germination index. From the experimental results, the maximum sunflower sprout germination percentage at 91.11% and the maximum germination index at 13.98 were obtained when the sunflower seeds were grown in the coconut coir with the solution prepared from earthworm manure bio-extracts, the higher germination percentage than that of a literature. The greenhouse with the developed in-house temperature and humidity controller has proved its performance in seedling sunflower sprouts and this feasibility study has shown that it had potentiality to be used in a household seedling application.