How to Grow Purple Sweet Potatoes

Botanical Names: Ipomoea batatas

Hawaiian sweet potato, which is a variety called ‘Okinawan’, but is commonly called purple yam, Japanese purple potato or Japanese Sweet Potato. It is noted that the first purple sweet potato was bred by the Japanese and grown specifically on
Okinawa, hence its name. The purple potato made its way to Hawaii and then to the U.S. mainland. Through its travels it developed many different names, but its real and true name is ‘Okinawan’. 

The other more recent purple sweet that has made it to the grocery is Stokes Purple sweet potato. Mike Sizemore, who lives in Stokes County, North Carolina, is noted for discovering this variety. In 2003, he was awarded these purple sweet potatoes as a prize at the state fair. The variety was unidentified and Mike began propagating it. In an article for the LA Times, it is believed that Stokes Purple is possibly a variety that was introduced by Japanese sweet potato breeders who had a number of purple varieties already in the marketplace. In all possibility, Stokes Purple could be ‘Okinawan’, but without genetic testing it is truly impossible to know. However, it is noted that ‘Okinawan’ is drier, lighter in purple color and less meaty when cooked compared to Stokes.

Growing ‘Okinawan’ sweet potatoes in U.S. climates can be done, but the variety was specifically bred for the weather that is consistent of the islands such as Okinawa and Hawaii. It is noted by professional sweet potato growers that it doesn’t prefer the conditions of the mainland. It prefers to be watered multiple times per day, likes rich, nutritious soil and sunny, warm conditions.  

Finding slips online can be a challenge, but if potatoes are found it would be easy to produce slips at home. Stokes Purple was discovered in 2003 and more friendly to U.S. growing conditions. The potatoes are easy to find due to the plant’s own website ( where you are able to buy them directly or locate a store nearby to purchase them. However, since the plant is patented, this means only those that have a license can produce it; so finding slips for home gardeners isnearly impossible. It is possible to produce your own slipls, but takes time and planning. 

As mentioned earlier, there are many different purple sweet potatoes that Japanese plant breeders have developed over the years. Here are some of the other varieties to consider that are easier to find and work well in U.S. gardens. Consider them when planning for your veggie garden: ‘AllPurple’, ‘Purple Majesty’ or ‘Purple Passion’.