Ginseng (Panax ginseng C.A. Meyer) is mainly cultivated in the Republic of Korea and China, and has been traditionally used as a medicinal plant in East Asia for the treatment of diseases such as hypertension, diabetes mellitus, liver and kidney dysfunction, mental disorders, and skin inflammation. Ginseng roots are cultivated after maturing at 3 to 6 years of age. The harvested ginseng roots are consumed and sold in various forms of products, such as fresh ginseng, red ginseng, and white ginseng. Ginseng is a shade-tolerant crop and requires shading facilities. It grows well with a light intensity of 10%, but its growth is hindered at light intensity above 20% due to high temperature. Therefore, it is cultivated with a light intensity set to 10% from April to October and harvested in October. However, if early harvesting is done in August to increase farm income, growth is low due to insufficient light. Therefore, a cultivation experiment was conducted with the light intensity set to 10% and 20% for the August harvest, and the yield and ginsenoside contents were compared with the October harvest. The yield of the 20% light intensity treatment group was 665 kg/10a, whereas the yield of the 10% light intensity treatment group was 572 kg/10a. The yield of the 20% treatment group was 16.3% higher than that of the 10% treatment group. According to the analysis on nine ginsenoside components including Rg1, the total ginsenoside contents in the 20% light intensity treatment group was 27.51 mg/g, which was 75.3% higher than that of the 10% light intensity treatment group at 15.69 mg/g. Specifically, Rg1, Re, Rb1, and Rc were 3.40, 7.29, 7.93, and 3.84 mg/g, respectively, more than twice as high as those in the 10% light intensity treatment group. Conclusively, a light intensity of 20% was determined to be optimal for maximizing ginsenoside cultivation for August harvesting.
