I've got no trouble sprouting organic sweet potatoes. Just place them in a cup of water and put them in front of a window sill. Nearly every variety of sweet potato is available as organic for a little extra price.

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However, I have trouble growing conventional sweet potatoes not labeled as organic. In particular, I have never been able to sprout the Okinawan purple sweet potato, because the only place that sells it in California is 99 Ranch and they don't carry an organic version. I have been told that the conventional sweet potatoes are laced with growth inhibitors to increase shelf life. I have washed the outside of this potato before and it still does not sprout. Is there anything else I can do?

I am aware Whole Foods sells an organic Purple Stokes sweet potato. I have indeed sprouted this one easily, but I don't want this variety. I want to the Okinawan variety which is much sweeter and smoother.

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  • I don't know anything about sweet potato growing in the US, but in the UK and Europe "non organic" root vegetables like ordinary potatoes are often treated with growth inhibitor to increase their storage life by preventing sprouting.
    – alephzero
    Commented Feb 20, 2021 at 17:53
  • ... some of these inhibitors are applied to the plant leaves before harvesting, and are transported through the whole tubers while the crop is still growing, so they can not be removed by surface washing. The tubers may have been washed anyway before storage, to remove excess soil, so a "wash-off" growth inhibitor would be useless..
    – alephzero
    Commented Feb 20, 2021 at 18:00

1 Answer 1


I'm in Hawaii and Okinawan sweet potato is quite common here. Due to this we don't always gobble them up right away and often tend to leave them in a basket for a longer time than most other areas. From what I've experienced, and I do know that most root veggies are treated with an inhibitor, but if you plan a little bit ahead (1 or 2 months), the inhibitor does wear off and the potatoes will start sprouting, even without ever being watered.

Same thing with ginger and turmeric. Onions and garlic start to sprout too without water. Just thought I'd tell you from my own personal experience with root veggies. If we don't eat them fast enough they all start growing and I put them in the ground randomly throughout the year. Plus we are almost always within 20° of 70° F.

  • Great info, and welcome to the site!
    – MackM
    Commented Feb 7 at 14:30

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