Growing Okinawan Purple Sweet Potatoes

By Liz Baessler | December 7, 2017
Image by HaJai
by Liz Baessler
December 7, 2017

When you think sweet potatoes, chances are you think of those orange fleshed things at Thanksgiving, maybe with marshmallows on top. While there’s nothing wrong with those, they’re far from the only sweet potatoes out there. Keep reading to broaden your sweet potato horizons.

History of Okinawan Purple Sweet Potato Plants

Okinawan sweet potato history is a funny one. Even though it gets its name from a prefecture in Japan where it’s extremely popular, it’s actually native to the Americas. It was picked up by European explorers sometime between 1492 and 1605 and carried to Asia. It especially took hold in Japan, and from there it travelled to Hawaii. To this day it’s an important staple in both places.

Okinawan sweet potatoes are also sometimes called Okinawan yams. This is due to a long history of confusion and conflicting opinions about what constitutes a yam or a sweet potato. We don’t need to get into that here – all you need to know is that both names deal with the same potato.

The potato in question has a pretty bland light brown skin, but the meat inside is a beautiful vivid purple sometimes streaked with white. The flavor is sweet and pleasant, and the texture is creamy. It’s very rich in vitamins and has been called a superfood. It maintains its purple color very well through the cooking process.

Growing Okinawan Purple Sweet Potatoes

Growing an Okinawan sweet potato vine is rewarding as long as you have the right climate. It can be grown like other sweet potatoes and needs a long, hot growing season. Plants tend to come as live cuttings that are transplanted directly into the ground.

Plant your cutting in a hill of rich soil. As it grows, add more soil to the hill – this will give the plant extra room to grow underground and protect it from weevils. You can usually harvest Okinawan sweet potatoes after 120 to 180 days.

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  • Maria
    Comment added July 29, 2021Reply

    How do we get purple color in the flesh? My spuds are more white than purple?

  • Keith
    Comment added May 19, 2021Reply

    I realize I'm coming to this post a few years late. But I do want to add a bit of info here. We lived in Hawaii for several years and Okinawa sweet potato is a staple there. Very delicious and one of my all-time favorite foods. I love it. Wish it was more readily available on the mainland USA.

    That said, the picture you have in this article is NOT an Okinawan sweet potato. You have pictured a stokes purple sweet potato that is much more common here on the mainland. Stokes has purple skin and purple flesh. Okinawan has ivory skin and purple flesh. The Okinawan is far superior in flavor and texture in my humble opinion. Raw, the inside of the Okinawan sweet potato is magenta to purple, often with white marbling. Once cooked, the flesh inside becomes a deep rich vibrant purple that leans to blue.

    Please use the correct photo, there is so much confusion online already about purple sweet potatoes, and you are adding to that by using the wrong photo. Makes me wonder if you have ever actually seen or eaten one. I'm not trying to be rude, but wish to correct the misinformation that is out there.

    As a side note that may be of interest to some of you, there are other purple varieties we saw and ate in Hawaii that I have never seen here on the mainland. Including a purple skin with orange flesh and a purple skin with white flesh. Both good, but my favorite remains the Okinawan.

    • Keith
      Comment added September 29, 2021Reply

      Thank you for correcting the photo!

  • Amy Mayemura
    Comment added May 29, 2020Reply

    I’m a first time attempting to grow Okinawan purple sweet potato! I just ordered from eBay
    what they call cuttings from a OPSP (Okinawan purple sweet potato). These were 10 stems that were not rooting yet. ?I have to put them in a jar of water placed on a sunny windowsill! I’m nervous/anxious hoping they will root! Then hopefully have enough warm weather to have harvest by November.
    Not sure what I’m doing but going to give it a shot! Not sure how long it takes for roots to show!
    My question is in researching I can’t find anyone who can tell me if you can start growing slips from the actual OPSP. YouTubed and can’t find anything on specific OPSP! I heard from the person I bought these cuttings from is he can’t ever get slips from the actual OPSP. So if successful I have to keep and grow stems from the vine?

    Looking for someone whose actually experienced in growing OPSP! Hope your out there!?

    • Eric
      Comment added September 26, 2022Reply

      Hey Amy. I just came across this article bc I'm growing the Okinawan potatoes now. From my experience, I haven't been able to grow slips from only this potato so far. But I have use cuttings from my already growing plants due to pruning.

  • Hatsuko Millette
    Comment added March 26, 2020Reply

    I want to buy 4 or 5 small plants to grow in my garden. do you know where I can purchase them.

    • LooLoo
      Comment added April 22, 2021Reply

      Baker Creek seeds company sells them.

  • Jake
    Comment added March 22, 2018Reply

    How many slips can I expect from each tuber? Can I expect a good harvest in zone 5?

    • Janet Chadwick
      Comment added November 29, 2021Reply

      Grow in a bag of potting soil so they have plastic to raise the temperature and moisture and simulate a tropical climate. Puncture one side of the bag with 6 evenly spaced holes. Place on concrete with wood slats underneath and the six holes down for drainage. Puncture the top of the bag with 4 evenly space holes and plant these holes with the slips. Cut a large hole in the center of the bag and water through his hole. Grow in full sun.

  • Ella Wilson
    Comment added January 24, 2018Reply

    Hey, Liz! Thank you for sharing this post! I never heard of Okinawan Purple Sweet Potatoes so thanks for this information. I got curious so I will definitely try planting this very soon!

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