Gingers grow from knobby roots called rhizomes.
The easiest way to grow culinary ginger is to buy a large root from the produce section of your supermarket. Let the ends dry for a day or two before planting. This is best done in spring, when the buds on the root are large and easily found. Plant the root sections in light shade or part sun, in rich, well-drained soil just below the surface, so they are barely covered with soil. Roots will rot in wet soil, so keep the soil moist but not saturated.