Growing sweet potatoes in a sunny vegetable garden produces a calorie dense tuber. The vines spread across the ground or can be trained up a trellis, making them a great addition to the landscape, even in areas that you might not normally grow food crops.
Bonus: The sweet potato vine is edible, too!
Here in Hawaii, and in other warm climates, growing sweet potatoes is like growing weeds. Trimmed vines tossed aside will root and eventually form an edible tuber.
The wilder areas of my yard are graced with purple sweet potato plants that have emerged from my compost. (Though admittedly, growing sweet potatoes like this doesn’t really net a big crop.) Growing sweet potatoes in containers is a more reasonable option if you live in a climate with a short season, as you’ll be able to start them early and move them outside after the weather warms.
Even if you live in a region with a shorter growing season than mine, you can harvest some of these tasty tubers. Sweet potatoes require a minimum of 90 days between planting and frost. The trick to growing sweet potatoes is to start early so you’ll be ready to get them in the ground as soon as your soil is warm enough. With a little forethought, home gardeners can easily enjoy the flavor of sweet potatoes grown right in the backyard.
Here’s something to consider about adding sweet potatoes to your garden: They are a calorie-dense vegetable. Here’s why that matters.
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Growing sweet potatoes – start with slips
Sweet potatoes are planted live cuttings called slips. You can start growing your own sweet potato slips so they’ll be ready for spring planting, even when it’s too cold to do any outdoor gardening.
Start by picking up a sweet potato from the grocery store. Choose organic if it’s available; some conventionally-grown potatoes are chemically treated to prevent sprouting. Push three toothpicks into the sweet potato at midway, spaced equally. Put the sweet potato into a recycled jar filled with water so that the bottom of the sweet potato is submerged. Set in a bright location.
This will look a lot like a grammar school science project.
The potato will begin sending roots down into the water within a few weeks. Soon you’ll see green shoots start to emerge from the upper portion of the sweet potato. These are the beginnings of your summer sweet potato crop!
Planting sweet potatoes
Sweet potatoes are easy to grow and prefer well-drained soil. Sandy soil works well. I’ve also had good luck with planting sweet potatoes in loose wood chips or mulch. They seem to like the loose growing medium and swift drainage.
When your soil reaches about 50 degrees F, it’s time to plant sweet potatoes. Cut 10″ to 12″ lengths of sweet potato leaves from your “seed” potato. Trim leaves from the lower portion of the slip, leaving a couple of leaves at the tip for photosynthesis. Plant each slip 6″ to 8″ deep, making sure that at least two leaf nodes are completely buried. I met one grower who actually plants a little bouquet of five of these slips per hole. Others plant just one. Both methods seem to work.
You can also cut the starter sweet potato up into rooted sections, as you see above. Plant those sections, burying them about three inches deep.
As the greens grow and spread, you’ll find that they try to root. Lift the vines once in awhile to prevent this. This allows them to use all their energy for producing large tubers rather than a lot of smaller tubers.
Getting started in cooler regions
If your region is really late in warming up, you can start rooting your slips indoors in pots filled with potting soil following those same steps. Keep the soil most but not wet. When warm weather finally arrives, you’ll have rooted cuttings to move out into the garden.
When are sweet potatoes ready to harvest?
I’ve been told that when the sweet potato plants begin to flower, it’s time to harvest. I’m not one to contradict an expert gardener, but I’ve planted quite a few crops of sweet potatoes and I’ve only seen them flower occasionally. I’m not sure that this is the best indicator! Instead, I suggest that you mark your calendar. Your sweet potatoes should be ready to harvest about three months after you planted them.
To harvest sweet potatoes that are growing in the garden, carefully loosen the soil in a wide area around the base of the plant. Don’t be surprised if you don’t find anything directly below the base of the plant. Sweet potatoes send out long roots and can develop anywhere on those roots. Gently sift through the soil (another reason to make sure your soil is light and loose!) until you’ve found all of the tubers.
Growing these tubers in containers
I’ve had good luck growing sweet potatoes in pots and raised beds. In particular, they’ve done well in grow bags. Sweet potatoes grow by forming tubers along their roots. Those roots can extend a good way from where you originally planted the sweet potato slips.
Growing sweet potatoes in pots allows you to keep them contained to a specific area. This also allows for harvesting without having to dig up a large area in the garden.
A purple sweet potato plant
While the orange fleshed sweet potato is probably the most recognizable, one of the more common varieties of sweet potato here is the Okinawan purple sweet potato. They are just stunning. I just discovered that Hawaii Veggie Farm ships Okinawan purple sweet potatoes by the box. I’ve never ordered from them, so I can’t give you any feedback on the company itself, but it might be a fun way to try something new in your garden!
Originally published in February 2014; this post has been updated.
I used to sprout a regular yam (as we call them here in Canada) in water – lots of roots and a very long time for the scapes or sprouts. Instead I put the yam into soil in a pot in a sunny window and it began to sprout pretty soon with lovely green leaves. When it was warm enough I moved the whole thing to the greenhouse awaiting warmer temperatures. I then removed the sprouts, placed them in light soil for a short while, so they would grow roots. Direct planting just wasn’t as good, as some leaves died. I have quite a few planted in my garden but the season may again be too short. Twice before I got finger-width yams, too young to harvest or eat. Yams also need to be seasoned in a warm, somewhat humid place for about a week. Then they will store well.
Good to note!
Sweet potato leaves! yum. Sierra Leoneans make a staple meal with them and I have been working to grow them in Portland OR for my Sierra Leonean friends who live here but do not have ANY gardening space. They have made some great meals and shared them with me; happy to share that recipe if asked!
I cannot find the plants with dark green leaves, though, and have been using the ornamental ones from nurseries, which taste fine, but my friends would love the darker green-leaved ones. I don’t know which variety of sweet potato has the dark green leaves… Also, the dark red leaved ones have not grown well for me. I tried doing both types in the house over the winter and did get a horrible infestation of gooey white blobs on the stems…now I know to try DE around them, thanks! Oh, and if growing them inside, watch out for the kitty! Mine eats the leaves at night!!
So I can actually eat the huge sweet potato which I dig up after my vine has been frozen. I didn’t realize I could eat the vine as well?
Yes, the leaves are edible!
Can I just cut the okinawa sweet potato into chunks and plant them directly into the ground during spring? I live in southern California.
Assuming your growing season is long enough, they will sprout that way, yes.
Thank you for your answer.
I submerged 1/2 of okinawa sweet potato in a jar of water, held in place with 3 toothpicks 10 days ago.I believe that I put the 1/2 where the roots would sprout in the water…. but it got rotten! The other okinawa sweet potato, I left it on the counter purposely for it to sprout, but a small part got rotten too.
Nothing have sprouted.
So what did I do wrong?
I have planted sweet potatoes for a lot of years.early on they were planted just in rows and not hilled rows and my amount of potatoes has really increased the loose soil really lets them grow beauregard’s get really big and even at 7 lb are still good makes real good sweet potato pies . also they don’t take a lot of water once they are growing.the smaller leaves are the best for salads.
Hawaii Veggie Farm radiates their sweet potatoes prior to shipping. It’s per USDA requirements for overseas produce. It states so on the shipping box. So their sweet potatoes will not sprout. Your best bet is to order okinawa sweet potato slips directly from either Rareseeds.com or SandhillPreservation.com
I agree with you about those okinawa sweet potatoes! They are the BEST!
By chance would you know what the name of the red sweet potatoes you have in the picture and where I could get a few of them so I could start slips from them – any information would be appreciated.
I’m sorry, I don’t! The purple/white ones are an Okinawan sweet potato. Those with the red skin/purple flesh are not as common. I’ll ask next time I find them, though!
You can just grow the plant in a hanging pot and harvest the leaves for stirfry and salads ….. edible and tasty, and easy greens to have when there is not much else around.
i just want the plant will it still grow a sweet potato …
It will still grow a sweet potato, but you don’t have to harvest it!
PL advise as to how I can grow a pretty plant from a bottle in my living room?What steps will I have to follow?
Just starting a potato in water (as you see above) will net a pretty substantial trail of (edible) vines. If you wanted to keep it as a houseplant long term, though, I think I’d transplant into a pot with soil. Fun project!
Can I grow sweet potato’s in a container or do they need to be in the ground? I don’t have a backyard to plant in. Thanks, Tami
I’ve not done it, but I’ve seen lots of people (online) doing it successfully!
We grew sweet potatoes in containers a few years ago.
We plan on growing them again this year now that we’re settled in a new place for a while.
I grew them in a big garbage can with composted straw.
My mom has been looking for the Okinawan Sweet Potato for YEARS!!! I saw the article about the Hawaiian Veggie Farm. I bought her a box of the fingerlings for her birthday (3/9) and we just got the box yesterday! 🙂 I told her how it’s yellowish on the outside and purple in the middle. She’s actually looking for an Okinawan Sweet potato that’s purple on the outside and yellow in the middle. Oh well, I tried…. 🙂 We’re going to cook some of the fingerlings tomorrow! 🙂
My mom is full Okinawan so that’s why she’s been trying to find the Okinawan Sweet potato!
Please ask your mother if Okinawan purple sweet potatoes have a purple skin and flesh or if they have a tan colored skin and purple flesh, like the ones grown in Hawaii? Thanks!
i believe those would be the Murasaki potatoes that are purple on the outside and white-ish on the inside. I bought some this year to try as I can no longer eat regular potatoes – they trigger pain for me. (Gurneys.com had them for sale)
Okinawan sweet potatoes actually originate from North America and not Japan. They were brought to Japan from indigenous tribes from North America.
I’ve never heard that before!
This is my second year growing sweet potatoes. Last year I harvested a great amount of purple potatoes, this year I am trying to sprout a Covington (orange) potato but even though I got it at the farmer’s market and it supposed to be organic, it’s not sprouting…. I think the temperatures in my house were a bit too low for it. Luckily, a friend gave me a few of the Hawaiian purples you mentioned, I am so excited to try them! He also said they are the best he ever tasted. Hopefully they’ll grow good here in the South.
How funny–my youngest and I did the sweet potato project this winter, just for fun. My family doesn’t really like sweet potatoes, either, so I never plant them, but now I’m dying to try the variety you mentioned. Ironically, I bought an organic sweet potato, and it never sprouted. The conventional one did, but it didn’t grow well. Isn’t that weird? I should have gotten it at our Farmers’ Market instead of the grocery store.
I just ordered 12 lbs. from the company you mentioned so I’ll let you know how they do! Thanks for all the info.
Last year I purchased 4 slips from a local garden center. I planted them in a mounded hill in a 4×4 area. I harvested 22 sweet potatoes. Some were very large. I stored them in my cool basement. We ate the last one this past January. They were 10 times sweeter than the store bought ones. That was my first sweet potato bed. Hurry up warm weather!!!!!