Purple sweet potatoes are gaining attention as an alternative to the traditional orange or yellow varieties often featured at Thanksgiving meals. Scott Stoddard, a University of California Cooperative Extension farm advisor in Merced County, said, “There’s a lot of interest in the purple sweet potato. It’s creating buzz, something new to talk about.”
Most sweet potatoes found in West Coast grocery stores originate from clones of mother plants propagated at UC Davis Foundation Plant Service and selected by Stoddard. In California, the acreage dedicated to purple sweet potatoes has expanded significantly over the past five years, now totaling around 1,000 acres.
Stoddard explained that growers are experimenting with at least six different purple varieties but are reluctant to disclose specific details. “Right now, it’s the wild, Wild West,” he said. “Nobody will tell you what they’re growing. It’s like, ‘my purple is better than your purple.’” Two notable varieties with both purple skin and flesh—Stokes Purple and Ben Yagi—are owned by a company. Another promising variety is an unpatented experimental type called Purple Rayne.
Jeremy Fookes, director of sales for A.V. Thomas Produce Company—which owns Stokes Purple and Ben Yagi—recalled challenges introducing these less common varieties to retailers. The Stokes Purple variety requires longer cooking times compared to moist orange-flesh types. “The first couple of years were a challenge,” Fookes said. “Stokes has to be cooked longer in order to make it moister inside, otherwise it can be chalky or pasty if you don’t cook it long enough.”
Interest in purple sweet potatoes increased after the Netflix documentary “Live to 100: Secrets of the Blue Zones” highlighted their health benefits due to phytonutrients such as anthocyanin. Following this exposure, demand for these varieties grew rapidly according to Fookes.
California accounts for roughly 25% of U.S.-grown sweet potatoes. The state’s growers faced difficulties after disruptions caused by the COVID-19 pandemic in 2020 led to decreased consumer demand and stagnant prices while production costs rose.
Sweet potato farming remains labor-intensive; although machine harvesters dig up the crops, each sweet potato is placed into bins by hand and later packed manually for shipment.
Most California production occurs in Merced, Stanislaus, and Kern counties. Over five years, total acreage has declined from more than 21,000 acres to about 18,000 acres as some growers shifted focus and four packing sheds closed.
Since joining UC Agriculture and Natural Resources as a vegetable crops advisor in 2002, Stoddard has worked with local farmers seeking improved red sweet potato varieties that store better and resist pests such as root knot nematodes. Although several candidates have been tested—including Burgundy (released in 2014) and Vermillion (released in 2021)—each presents unique advantages and drawbacks.
Because there are no dedicated sweet potato breeders in California, Stoddard collaborates with Louisiana State University breeder Don La Bonte on trials involving new lines each year. According to Stoddard: “Four of the six most important commercial sweet potato varieties grown in California started with the LSU breeding program.” One such variety is Bellevue—a high-yielding type resistant to root knot nematodes—that was formally released in 2015 after extensive testing.
Bellevue now comprises about 15% of California’s crop acreage and is also cultivated internationally across Canada, Europe, North Africa, Australia and New Zealand.
California growers have carved out a niche for organic production due to favorable pest conditions that reduce reliance on insecticides—a contrast with other U.S regions where insect pressure is higher.
Cooking methods play an important role in flavor development for these tubers. For yellow or orange types, Stoddard recommends baking them at 375 degrees Fahrenheit for an hour. Fookes suggests that Stokes Purple should be baked slowly at lower temperatures—between 250–275 degrees Fahrenheit—for up to two hours: “You only get caramelization through the low heat, slow baking process whether it’s foil-wrapped on a barbecue or in a pan in the oven,” he said.
