The purpose of this study was to investigate the effects of root zone temperatures (RZT) on the germination of bell peppers and tomatoes. Bell peppers and tomatoes had the highest germination rates (85% and 90%, respectively) at 25oC air temperature. Besides, the first germination of bell peppers was shifted by one day ahead. Bell peppers had the highest germination rate of 72,100, and 100%, respectively, when the RZT was adjusted to 30oC at airtemperature of 20, 25, and 30oC, and when the air temperature was adjusted to 35oC, the germination rate was the highest (70%) when the RZT was 15oC. Tomatoes had the highest germination rate at 20oC of the RZT at all atmospheric temperatures. A local cooling and heating system was established to improve the germination rate by controlling the RZT during the low and high temperature period. The optimum RZT for seedlings during the low and high temperature period was investigated.