The effects of cultivation methods (cultivation of curled-shaped type, M-1; conventional cultivation, M-2; growing after treatment with a growth regulator, M-3; cultivation by the combination of M-1 and treatment with oak charcoal, M-4) on the quality characteristics of soybean sprouts were studied by the measurement of growth characteristics. This study also investigated the changes in shelf-life stability of the new soybean sprouts (NSB) using M-4, which was cultivated with oak charcoal and treated with antimicrobial Citrus sunki seed extract. Among the soybean sprouts grown for six days at the high temperature and humidity environment (90$pm$5% RH, 25$pm$1$^{circ}C$), M-1 revealed no significant difference in terms of quality, such as the harvest yield, the rot rate and the growth characteristics when compared with M-2. M-3 showed no significant difference in growth characteristics, of hardness, and sensory evaluation scores when compared with the soybean sprouts grown by conventional methods. NSB had a low number of total microorganisms and had a better appearance after five days of storage than did the control group (M-2). These findings demonstrate that chemical-free and clean soybean sprouts can be grown by combining oak charcoal and antimicrobial Citrus sunki seed extract, thereby meeting the consumer demand for safe, chemical free sprouts.