Q: After reading a suggestion in your column last winter, I planted a piece of ginger root from the grocery store. It grew outside in a pot all summer. Recently I dug up a few roots and found that they were sweet and delicious. There are, however, even bigger roots growing from the base of the plant. Are all ginger plant roots edible?
A: Glad you had fun with your experiment! The thick roots growing horizontally from the base of the ginger plant are called rhizomes. They are specialized, starch-filled structures. The slender roots that extend downward from a rhizome extract water and nutrients from the soil. A by-product of the energy-storing work of the rhizome is a chemical that gives the nice gingery taste you enjoy.
The newly-grown rhizomes are delightfully edible but the old one you originally planted is too tough and woody to consume. Ginger is not always winter-hardy outdoors in Atlanta. You can bring the plant indoors for the winter or experiment further by planting it outdoors in a protected location. If you don’t care for those two options you can always plant grocery store ginger root next spring.
Remember that butterfly ginger, Hedychium coronarium, is not the same as edible ginger, Zingiber officinale.