TWIN FALLS — Potatoes are in Idaho’s DNA. But for all the Gem State’s spud supremacy, the sweet potatoes on your Thanksgiving table almost certainly didn’t come from here.
Sweet potatoes — which aren’t actually potatoes — and regular potatoes require very different growing conditions.
Idaho’s agricultural strength often stems from its hot days and cool nights. Sweet potatoes tend to do better in more tropical environments.
“They need really hot temperatures for a long period of time,” University of Idaho Extension Horticulture Educator for Twin Falls County Andy West said.
It takes about 150 frost-free days to grow sweet potatoes, and Idaho can’t meet those conditions. Sweet potatoes do better in more fertile soils too, while Idaho typically has sandy, silty loams along the Snake River.
West grows sweet potatoes in the Magic Valley but has a greenhouse for his plants. He said he planted about 50 sweet potato plants this year and got about a gallon bucket’s worth of tubers at season’s end — a much smaller return than he’d have seen with plain potatoes. He tried growing more sweet potatoes outside this year, but the plants in the greenhouse fared better.
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The vast majority of American sweet potatoes come from southern states. North Carolina is the country’s sweet potato capital and has been for the past half-century. The Tar Heel state typically accounts for about 60% of the U.S. harvest.
Last year, North Carolina harvested 78,500 acres of sweet potatoes according to the U.S. Department of Agriculture. That was more acres than the next five top sweet potato producing states — Mississippi, California, Louisiana, Florida and Arkansas — combined.
Spud production runs laps around sweet potato production, even though Americans have been eating more sweet potatoes because of their high vitamin, mineral and fiber content.
In 2018 Idaho harvested 315,000 acres of spuds according to the U.S. Department of Agriculture. The runner-up for American potato production, Washington, harvested 160,000 acres. North Dakota, Wisconsin and Colorado round out the top five for spud production.
Idaho has conditions that places like North Carolina don’t. For instance, University of Idaho Extension Crops Educator Steven Hines pointed out that Idaho has the benefit of a consistent water supply.
“Good, consistent irrigation is one of the keys to growing good potatoes,” Hines said.
Idaho’s temperatures have benefits too, even if the state doesn’t have as many warm days. Cool nights help farmers fend off diseases on their crops for example.
More farmers could switch to traditionally tropical crops in the future, West said. Some are testing the viability of more fruit and nut trees in Idaho.
West said it appears almonds could produce a crop only once every four years here. But they’re so valuable that one good year for every three down years could still be profitable.
So Idaho might start growing almonds, but for now, the Magic Valley might stick to its strengths and grow potatoes, barley, sugar beets, alfalfa, beans and corn.