A Brief History of the Sweet Potato

Sweet potatoes are one of the world’s oldest food crops, predating the Irish (white) potato by centuries. Earliest cultivation records date to 750 BCE in Peru, though archeological evidence indicates they were growing much earlier than that, between 2500 – 1850 BCE.

Conventional thinking has held that Columbus was the first to introduce Ipomoea batatas outside the Americas, but recent scholarship challenges this idea.

Sweet Potatoes in Prehistory

The presence of prehistoric sweet potato remnants found in Polynesia, in the central and southern Pacific Ocean, and carbon dated to between 1000 and 1100 A.D., long teased at the possibility of contact between islanders and South America hundreds of years earlier. Linguistic evidence exists as well. The Polynesian word for sweet potato, ‘kuumala’ and its variants, resembles the Quechuan one, ‘kumara’ (or ‘cumar') and ‘cumul’.

In 2013, researchers who conducted a genetic analysis of more than 1,200 sweet potato varieties from Asia and the Americas asserted their findings as evidence that Polynesian explorers visited the New World hundreds of years before Columbus.

Some scholars believe that Polynesian explorers used a boat like this one to make the long-distance journey to South America.

But given that sweet potatoes have spread and interbred for centuries, the researchers needed a way to establish an early genetic map of the sweet potato before it became a global crop.

It's in the Genes

Using the dried remains of sweet potatoes that British explorer Capt. James Cook and his crew collected during a voyage to Polynesia in 1769, French researcher Caroline Rouiller and her colleagues were able to trace the root vegetable all the way back to Ecuador and Peru.

However, in a 2018 study, another set of researchers came to a very different conclusion: sweet potatoes dispersed all by themselves, without human intervention. Their research pointed to a single wild ancestor of all sweet potatoes, Ipomoea trifida, which grows in the Caribbean and has pale purple flowers resembling those of sweet potato.

Using DNA sequencing techniques, they further concluded that Polynesian sweet potatoes – which are genetically distinct from other types they studied – split off from other types more than 110,000 years ago. Given that humans arrived in New Guinea 50,000 years ago, and in Polynesia much later than that, it is impossible that humans played a role, said lead researcher Pablo Muñoz-Rodríguez, a botanist at the University of Oxford.

A Key Crop for Food Security

While the debate over their specific origins remains unresolved, this relative of the morning glory is one of the world’s most widely cultivated crops. Sweet potatoes are adaptable to a wide range of growing conditions, cultivated as a perennial vegetable in tropical conditions and as an annual in cooler climates. Globally, we consume more than 136 tons of sweet potatoes each year. Sweet potatoes are seen as a key crop for food security, especially in an era of climate change. They grow quickly and can tolerate less-than-ideal soil conditions, and, relative to many other crops, they use water very efficiently.

They’re also delicious and incredibly versatile, not to mention highly nutritious!

A Rich and Delicious Culinary History

Columbus did indeed bring Ipomoea batatas to Spain from the Americas, and the plant quickly spread in Europe. Englishman John Gerard included it in his 1597 Herball, suggesting that eating sweet potato “comforts, strengthens, and nourishes the body,” and proclaiming its qualities as an aphrodisiac.

A painting of herbalist and botanist John Gerard, whose voluminous Herball was published in 1597 and remained influential in the 17th century. From the Wellcome Collection, in the public domain.

Sweet potato was being grown in what is now Virginia as early as 1648. By the 1700s, Native Americans in the region were growing it extensively, and Ipomoea batatas spread both north and south.

Though it is grown and consumed in other parts of the U.S., sweet potatoes are indispensable to the foodways of the American South.

Selected sweet potato recipes of George Washington Carver, tested in the laboratories of the Bureau of Human Nutrition and Home Economics, 1944.

During his time at Tuskegee Institute (now Tuskegee University) in Alabama, agriculturist and inventor George Washington Carver developed more than 100 uses for sweet potatoes, including recipes for sweet potato bread and sweet potato pie.

Grow Your Own Piece of History

Many of the outstanding heirloom varieties we offer were developed and improved in the American South, including Carogold, developed from the Gold Rush sweet potato at Clemson, in South Carolina; and Nancy Hall, a sweet potato variety once so popular that the folks of Paris, Tennessee, held a “Nancy Hall Sweet Potato Jubilee.”

Key takeaways:

• Sweet potatoes are one of the world’s oldest – and perhaps the oldest – food crops.
• Sweet potatoes are a global crop, but their precise origin remains unsettled.
• Globally, we consume more than 136 tons of sweet potatoes each year.
• Sweet potatoes are seen as a key crop in an era of climate change, as they are adaptable, nutritious, productive, water efficient, and tasty!

About the Author:

Michelle Johnson wears a lot of hats here at Baker Creek, but perhaps her favorite role is that of seed historian. She produced many of the Seed Stories videos on our YouTube channel (and yes, that's her voice narrating many of them!) and frequently contributes stories to The Whole Seed Catalog. With decades of experience as a journalist, both in print and on the radio, she is delighted to use her reporting skills to dig in to the history of seeds and the people who grow them.