Extension@YourService: Sweet Potato Season Once Again!

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Sweet potatoes are almost as obligatory on the Thanksgiving table as the turkey itself. It’s a humble vegetable, but there is much more to it than simply a carrier for brown sugar, pecans, and marshmallows. First of all, were you aware that the Center for Science in the Public Interest named sweet potatoes as one of THE most nutritious food you can eat? They’re loaded with dietary fiber, beta-carotene (vitamin A), potassium, vitamin C, and vitamin B-6. The CSPI listed sweet potatoes number 1 of all superfoods! Not only are they healthy, but they are also really delicious. If you’re used to eating them with brown sugar and marshmallows, try them with just a little butter – or a tad of salt and pepper! The salt brings out the sweetness nicely.

Sweet potatoes are an interesting vegetable. They are close relatives of morning glories, the vining annual with bright blue or purple flowers. Both are in the genus “Ipomea”, which is like being first cousins in the human world. Here in the south, “sweet potatoes” and “yams” are terms often used interchangeably, however, they are actually completely different plants. A yam is a starchy edible root typically grown in the Caribbean. It is rough and scaly on the outside and the pale, creamy flesh is very low in beta-carotene. If you remember back to your 7th-grade biology class, all flowering plants are either monocots (such as grasses and palm trees) or dicots (flowering plants that are not grasses). Yams are monocots, and sweet potatoes are dicots, so they are extremely different types of plants. Feel free to continue to call your sweet potatoes “yams” (the “word police” will not come after you!), but now you have some fun, non-political information to share around the Thanksgiving table.

Not only are sweet potatoes delicious and nutritious, but they are also incredibly inexpensive. In the grocery stores, they can be found for just $.99 per pound. That’s a huge value, especially when one considers all the work that goes into growing a sweetpotato. For one thing, sweet potatoes are susceptible to several viruses. The North Carolina State University’s Micropropagation Unit and Repository produces special, virus free plants that are then sold to certified sweetpotato producers throughout the country, who use the plants as source material to raise slips, a fresh sprig of leaves and stem with a few extra roots has developed. Slips are grown in large beds starting in late winter, then cut in late spring. Typically, farmers buy slips from a certified source (though some do grow their own), and transplant the slips in late May or early June. Depending on the variety, with weather as an additional factor, it takes between 90 and 110 days to grow a sweetpotato. Weeds, water, and pests must be managed during that fairly long growing season. Sweet potatoes are relatively pest resistant, however, management of soil-borne insects are critical, as their presence can damage the tubers and make them unmarketable. Once they are mature, sweet potatoes are dug using a special plow that flips the potatoes up out of the ground so they lay on top of the soil to be harvested. Because of their delicate skin, sweet potatoes must be harvested by hand, not mechanically, which would result in too much scaring. The harvested potatoes are placed in large bins and cured at warm temperatures for a few weeks, to enhance the sweetness of the flesh. Either in the field or post curing, potatoes are sorted into sizes for sale: number 1s, jumbos, and canners (the smallest) are the typical grading categories.

If you need a final reason for adding sweet potatoes to your table, this Thanksgiving and beyond: North Carolina is the number one producer of sweet potatoes in the country. It’s pretty easy to “buy local” for this product, and there are several local producers in the Sandhills. Confirm that the sweet potatoes in the grocery store are from NC (sometimes they are not!) and encourage the stores to buy local if they aren’t already. In 2017 NC had about 90,000 acres of the crop, and NC is responsible for about 45% of the sweet potatoes grown in the country; Mississippi is number 2, responsible for about 20% of the country’s production. There are a number of different sweetpotato varieties, with different flesh colors (red, orange, white, and even purple!) and skin color variations. Textures very, as well as other qualities, so taste test some and determine which is a fresh sprig of leaves and stem with a few extra roots have developed your favorite. Some say the white sweet potato is a good substitute for Irish potatoes for those with diabetes, but any sweet potato is a good choice, with more fiber and a lower glycemic index than Irish potatoes.

This year, due to two hurricanes during the growing season, it’s uncertain how the NC sweet potato crop will be affected due to flooded and waterlogged fields. Because of food safety concerns, edible crops are not able to be harvested if fields are flooded by nearby river or streams. Fields that are waterlogged from excessive rain are not condemned, however, sweet potato quality may be significantly impacted after a few days of low oxygen, waterlogged conditions. However, Sandhills sweet potatoes should be fine, thanks to our well-drained soils.

So, enjoy your sweet potatoes this Thanksgiving season, and hopefully, beyond! It’s good for you, delicious, and supports our local farm economy as well.