Ginger is propagated by using its rhizome. A rhizome is a modified stem that grows horizontally underground and produces roots and shoots from its nodes. When planting ginger, the rhizome is cut into pieces, each with at least one bud, and then planted in the soil. The rhizome will then sprout and develop into a new ginger plant. This method of propagation allows for the production of genetically identical plants, which ensures consistency in the crop yield and quality.