Sweet Potatoes

Sweet Potatoes and Their Rooting Vines – Answering a Reader’s Question

After searching TMG and not finding the answer to his question about sweet potatoes, friend and reader, Jim, from Illinois sent the following question to me:

–I heard that sweet potato vines will want to send down roots (from the vines) if the soil is moist, and that you should gently pull up the vines every so often to check that these vines are not setting down roots which will significantly reduce your potato yield. The only place roots should form is at the parent plant.

This is the first year I’m growing sweet potatoes and I just wondered if you have any experience with this? I can see how this would kinda make sense, but also wonder how additional roots can be a bad thing??

Replying to Jim, I told him that in all my years of gardening I’ve only grown sweet potatoes one year. I had no room in my garden that year and tried them in a flower border. The voles got them all.

Turning to a Long-time Friend and Gardener for the Answer

Fortunately, I have a friend whom I knew would be able to answer the question. My long-time friend, Charles, grew up on farm and has gardened for more than 50 years. And he knows his stuff. And when he visited me today, I was ready with Jim’s question.

Charles said when he was a kid growing up they use to cut off the running sweet potato vines and feed them to the livestock. He said the supposed purpose was to make use of the vines and at the same time not allow them to root and take energy away from the main plant that was producing the sweet potatoes.

He was quick to say that they never tested the “theory” — but that’s the how and why of how they handled the runner vines on the farm years ago.

So evidently what Jim heard or read goes back many, many years.

At the beginning of the growing season Charles continues that practice even now until he gets bogged down with other chores as the season progresses. Then he just lets them grow and do what they want.

No Sweet Potatoes Form Where The Vines Root

This long-time gardener also pointed out that where the vines root, no sweet potatoes form there. HOWEVER, if you cut the vines away and transplant the section of the plant with the new root, it will give you sweet potatoes! (As I type this, I’m wondering if you could just cut the new root off from the parent vine and let it grow in place by itself and get potatoes?)

Starting Your Own Sweet Potato Slips

Most of us have seen someone put a sweet potato in a jar of water and have it put out shoots (slips) which can be transplanted to the garden.

Charles suggested a way to start slips that is much more to my liking and he said the soil in my garden would be perfect for this method. (Be sure to use sweet potatoes that have not been sprayed with sprout inhibitors as those at the grocery store are.)

The number of sweet potatoes you use will depend on how many sweet potato slips you want to grow. Each potato will give quite a few slips. Better have more than not enough in my opinion.

Once you have the potatoes, plant them horizontally about 4 inches down in good garden soil in late winter once you know the ground won’t freeze again. He suggested late February or early March here in our area (Virginia – zone 7).

When nature gives the potatoes the right cue, they’ll send up sprouts. You can lift those up and transplant them to start your sweet potatoes. Plant as many of the sprouts as you have room for. (I’d guess about 18 inches apart.)

Other Things Charles Has Shared With Me In the Past

By the way, I’ve mentioned things Charles has shared with me before. Long time readers will recall the story about Charles pulling up tomato plants on the farm and hanging them in the barn allowing those green tomatoes to continue to ripen long after frost.

Another story about potatoes and voles is in the book (Organic Gardening, Cutting Through the Hype to the 3 Keys to Successful Gardening) on page 221.

Final Thoughts

If you’ve raised sweet potatoes for years, why not share some of your expertise with rest of us in the comments below.


  • I have grown Beauregard sweet potatoes for several years. I save some and make my own slips. I did not know about snipping back the runners, but until this year the rabbits have done that for me! I always get a decent crop of sweet potatoes. Now that I have the rabbits fenced out, this article has me thinking about clipping the runners in place as an experiment.

    When I harvest them before the frost, I let them dry, shake but do not wash off the dirt, and wrap them individually in newspaper to store in a cardboard box under a bed or closet. They keep all year this way, and I have to root them myself to get the next year’s crop.

    The voles take bites from some of mine too, but this year I have a big rat snake living in my garden! Yes!!

  • Betty, I envy your having a rat snake!

    Did you all know that sweet potato vine is edible? I believe that it is common in Korean cooking. I also have read that if you clip the vines regularly, your potatoes will be larger!

    We haven’t grown sweet potatoes in decades. We just don’t have the room here!

  • My question is, Maybe if you don’t get sweet potatoes from the vines, maybe the next year you will more, especially if you don’t harvest them the first year, Just a thought or question. Maybe Winter will kill everything anyway and all you will get is the potatoes that grow from the old potatoes left in the ground.

    I don’t know, have only grown several kinds of regular potatoes, My Irish blood I guess.

  • We have grown sweet potatoes for years (Zone 4), but have never clipped the vines. When we plant sweet potatoes, we mound up dirt a good 18 inches and cover the mound with weed guard. We have cut holes in the weed guard at the top of the mound and then plant the sweet potato slips in the holes. We start our slips from a sweet potato we put in dirt and keep in the house all winter. After the slips are planted, we cover the whole mound with grass clippings to help with moisture and weed control. We will definitely try cutting back the vines this year – our turkeys would LOVE them! Thanks so much for the wonderful post! I love the information found here!

  • I have grown sweet potatoes for several years and do not worry about the vines rooting and have gotten sweet potatoes in the oddest places far from where I planted the slip. I plant them in my flower garden and the vibes meander amongst the flowers.

  • Interesting. Last year I let them ramble and the yield was not so great. This year I planted them, 10 slips,in a 12x4ft raised bed and will clip off all the runners that try to escape. The best part of growing them last year was discovering just how delicious the leaves are, everyone thought they were better than spinach or kale. And the plants didn’t seem to mind having the leaves harvested.

  • We have never cut back the vines (they are just beautiful), although sometimes I do pick them all up en masse and hurl them back on top of the plants when they get out of control. We have always had so many sweet potatoes we run out of things to do with them, and have never had anything sprout from the vines. In fact, this year, I was so sick of them I did not plant them!!! Not surprisingly, they do very well in our Carolina clay!!

  • I’ve been growing three slips of Molokai Purple sweet potatoes in a 20 gallon fabric pot. I mainly planted them to round out the “Hawaiian Corner” of my garden with my Hibiscus and Plumeria. The vines don’t seem to be rooting too heavily in the straw mulch around the pot, but they’re too entangled with my out-of-control cantaloupe vines to up root anyway. The only trouble I seem to be having is caterpillar damage to the young leaves. I just noticed this a few days ago. The young, purple leaves seem almost “glued” together and full of holes. When I pry them open, there’s always one or two green caterpillars having themselves a feast.

  • Got an email from Charles giving additional information that I wanted to share:
    “I forgot to tell you — once the plants start to put out runners dirt should be mounded up around the plant to give the new potatoes soil to develop in. Also sweet potatoes must be dug prior to frost in the fall. If frost hits the green vines if will not only kill them it will make your potatoes rot in the ground.”

    Amy also email and offered the following input:
    “I typically weave the vines back and forth across the bed and bury most of the rooted bits as they grow. I could swear I got some smaller sweet potatoes at some of those points within a 4 foot or so radius of the original plants but it’s hard to tell given how packed the bed was. I also have made a teepee out of bamboo. About 15+ feet tall! Planted sweet potatoes and zinnias around it. The 4-H’ers absolutely loved going inside the teepee as the vines grew up it and made a hideout. The yield of that area where I wasn’t burying the rooted bits was definitely less leading me to believe I did get some from where I buried the roots.”

    Thanks to all for taking time to comment.

  • Yes, sweet potato vines do grow sweet potatoes. Of course they are going to be smaller compared to the main plant unless it’s left in the ground for a longer time. You can harvest the main plant and leave the rest of the vines in the ground especially if you live in a warm climate and don’t have to worry about frost. Once the roots from the running vine is attached to the ground it will be strong enough to make a potato in time. I have noticed that the Bush variety sends out more roots than the others.

  • I’ve only grown sweet potatoes for maybe five years but I have definitely had small tubers form where the vines/runners had time to drop decent roots. I’m in zone 6 so the tubers that formed from the vines rooting were maybe 3/4″ in diameter and 4″-5″ long at most when harvesting in the fall. Most were much smaller than that but they appeared to take energy away from the base plant since despite prolific growth of the vines I would have just one large sweet potato or maybe two medium ones but that was it aside from a bunch of the mini sweet potatoes from the vines rooting.

  • I grow lots of sweet potatoes each year and each year I learn a little more. If you break the roots from the soil along the vine at least once, any roots should at that point would/ should turn into fibrous roots as opposed to storage roots. That’s at least the theory. It’s also why I plant my slips without roots this year, so they can form in the dirt without concern of damage. Last year’s sample size proved they were more productive.

  • Great input Mike. Thanks for sharing your experience. Very interesting.
    I know I’ll keep this in mind when I grow sweet potatoes again.

  • When you say that sweet potatoes love full sun you’re not talking about full Texas sun. I have to shade my potatoes with a 40% shade cloth or they turn brown with sunburn.

  • Hello,
    After reading your article, I had to do an experiment,
    so, I grew 6 sweet potatoes,
    #1 I let go wide, what ever it wanted to do
    #2 I cut the vines short
    #3 I let the vines grow 3 feet then cut them at 3 feet
    #4 I let grow 5 feet but kept burying the vine as it put down roots
    #5 I let the vines grow 8 feet and take root
    #6 I kept the vines cut at 0 feet never gave it a chance to root

    Results were that a trimmed vine that roots, will in fact produce a sweet potato
    #2 and 6 produced poorly
    1 3 4 and 5 did fantastic, bringing in near record weigh ins
    the top best result is #4 and 5

    So the answer is yes, vines can and will grow tubers if allowed, and does not effect
    the over all weight of the tubers at the plant.

    One more tip, if you want the vines to also produce, as soon as the vine roots, cut the vine on the plant side, and it will form another plant, with awesome results.
    We send our extra to a food bank.

    Hope this helps

  • Thomas Campbell, Thank you so much for that hard data! I scoured the internet for a WEEK looking for just the sort of concise info you posted (Oct. 2023, on your Sweet Potato vine experiments). I was especially searching to learn the effects of ‘cut(ting) the vine on the plant side’ of rooted nodes along a running vine and whether that would form another bearing plant. For I had started to bury the vines as they ran speedily away from the seed potato. And, as each buried node began to sink roots, I noticed a new vine sprouts off the side. So it got me wondering if I cut these off from the main vine, whether they would become a bearing plant. None of the Cooperative Extension documents I found had any such details!

    Bravo, sir!

    County Agents: take note! Your constituents want and need hard data, experiment results, cause & effect and the like spelled out for us like Mr Campbell did.

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