Going back to your roots…or tubers…or bulbs…or corms

Diane Wright Hirsch, MPH

Senior Extension Educator


vegetablesCorms? What are corms?

This time of year, those of us who make an attempt to eat seasonally, “root” vegetables are a mainstay. Though most are available year round, roots are something that you can continue to find at your local winter farmers market—grown in Connecticut. At my New Haven market, I have seen carrots, beets, radishes, all types of potatoes and even celeriac or celery root.

But, after doing a bit of research, prompted by an article sent to me, I discovered that what most of us know as root vegetables, may not actually be root vegetables as a knowledgeable botanist could tell you.

True root vegetables include taproots and tuberous roots. Taproots grow downward into the ground. They tend to be drought tolerant, sending out roots 20 to 30 feet long in search of water, if necessary, in dry climates. Typically they are tapered in shape: a main root with other roots that sprout off the sides.

Taproots include beets, parsnips, carrots, turnips, radishes, rutabaga, jicama, salsify, celeriac, and daikon radish. This list is not exhaustive and does include several taproots that appear to be shaped more like a ball than a tapered carrot. Tuberous roots are modified lateral roots, many of which (sweet potatoes, cassava) look just like taproots: others look more segmented such as ginger or turmeric.

Corms, rhizomes and tubers (different from tuberous roots) are really stem structures, not true roots. But many a roasted root vegetable recipe will list them as ingredients. Generally speaking, they are referred to as roots in agriculture as well as culinary uses.   Corms, constructed of vertical underground stems, include Chinese water chestnuts and taro. You no doubt have seen taro chips in the snack food aisle in your local grocery store or fancy food shop. They are often used by higher end restaurants as a garnish as well. They are an off-white color with dark striations and have a nutty flavor. In Hawaii, taro is cooked, mashed and made into poi, a thick liquid, often eaten with the fingers.

Rhizomes are also stems, not roots. Not all rhizomes grow underground, but ginger, ginseng, turmeric and lotus roots do. When growing, they look like a mass of horizontal roots (though, again, they are NOT roots).

Finally, tubers are a class of root-like vegetables that include potatoes, and some varieties of yams. They are formed from thickened underground stems.

Historically, because they are inexpensive to grow and store, root vegetables were often considered to be food for the poor. But the richness of a diet high in colorful beets, carrots, potatoes and sweet potatoes, flavored with garlic or shallots (which are bulbs, not roots), turmeric, ginger or radishes is something we can all benefit from.

One thing that all of these true root vegetables, corms, rhizomes, and tubers have in common is that they serve as storage organs for the plant. They are a major source of carbohydrates, the nutrients that provide energy essential for plant growth and metabolism. Often these vegetables are placed on a do not eat list for those trying to cut down on carbohydrates. This would be a mistake, though. These carbohydrates generally digest more slowly and contribute to the energy needs of the human body, just as they do for the plant. Not only that, but they are also great sources of fiber (for heart health and gastrointestinal system health) and phytonutrients, which are not vitamins, but chemical compounds that have antioxidant and anti-inflammatory properties in humans.

If you have a backyard garden, consider adding root and root-like vegetables to your “to plant” list this year. They are not difficult to grow if you pay attention to soil quality. They grow best in a deep, loose soil that can hold moisture, but is well-drained. Root crops do not grow well in very acid soils. So, don’t forget taking a soil sample so that you will know if you need to treat with fertilizers or lime. Planting of root vegetable crop seeds generally begins early in the season—as early as the beginning of April for most in Connecticut.

For more information on growing, preparing or storing root vegetables, contact the Home and Garden Education Center at ladybug@uconn.edu or 1-877-486-6271.