Some potatoes seem to be slow to get leaves or roots. I'm experiencing the opposite with one of mine. It has a shoot but no roots. I've moved the skewers so that the potato will sit lower in the water. Hopefully that helps.
In your case I think you may just have to be patient and make sure it's getting enough light. The fact that it has roots means it's doing ok.

Hi, are you growing them from the bulb or from a cutting?

ianna

Hi ianna;
I'm finally able to reply to your question--- been having trouble with my browser the past few days-- anyway, I started my sweet potato vine out by putting the potato itself in half a glass of water (using toothpicks to keep the top half out of the water). It's been about four weeks now, and there are lots of roots on the bottom, but nothing at all happening on the top. Do you think I should plant it now or wait?

Is that how you grow sweet potatoes? I was wondering! I have done potatoes in the past, but never sweet potatoes. Are they hard to grow? So am I supposed to get a couple of sweet potatoes, stick them in water so that some of the roots are showing and put them in a window that gets lots of sunlight? And then once the roots and shoots form than you can plant them in the garden?

I love sweet potato! I hope this works. Can I cut the potato into 4 pieces to have 4 seperate growths, or do you need 4 whole sweet potatoes?

If it has roots, that's a good sign. Sometimes I think it just takes a bit to break dormancy and sprout leaves. I take cuttings in fall and grow my sweet potato vines as a houseplant for winter, the cuttings root easily in water as well. I also have taken in the small potato tuber and stored that as well. Sometimes those take a bit more time to break dormancy, but they usually do.

Lilacgirl, not sure. If you cut the tuber into pieces, maybe they might be inclined to rot in water? Maybe just planting in moist soil would work best in that case? Not sure, are we talking about the ornamental sweet potato vine or the grocery store ones. I think they are very similar, but not sure.