This experiment was carried out to investigate the effects of compost mixed with microorganism compost fermented for the production of high quality plug seedlings of tomato and red pepper. The results are summarized as follows. As a result of compost analysis, EC value was increased with increment of microorganism compost supplemented but lowered gradually in the late period of seedlings growth, pH value of microorganism compost fermented was 9.3 which is strong alkalinity. In the plot of 30 percent of microorganism compost fermented early growth of tomato seedlings was better in terms of plant height, leaf area and total dry weight. However, early growth of red pepper seedlings was shown in the plot of supplemented with 20 percent of microorganism compost fermented. The higher the mixing rate over 60 percent of micrroganism compost fermented to the soil used retarded the seedlings growth regardless of tomato and red pepper.