The effectiveness of three bio-extracts: Chinese kale, Chinese cabbage and soybean on Chinese
kale growth was compared. The nutrient composition and chemical properties of the three bio-extracts
were investigated. The various concentrations of each bio-extract were applied daily to the supporting
media, to enhance Chinese kale growth. The height, fresh weight and dry weight of the Chinese kale
were measured for both stems and leaves. The results showed that the acidic condition of all bio-extracts
had a high electrical conductivity (EC). However, the nutrient concentration in each bio-extract was
noted to be less than that of the complete nutrient solution. Furthermore, soybean bio-extract performed
the best in the most acidic conditions, had the highest EC values, and the greatest amount of total
nutrients. Chinese kale and Chinese cabbage bio-extracts performed similarly in terms of chemical
characteristics. With regard to growth enhancement using these bio-extracts with determined
concentrations, a complete nutrient solution gave the best height and both fresh and dry weights, and
showed a significant statistical difference from the other two bio-extracts. Soybean bio-extract was the
most effective bio-extract to enhance growth.