Grow Your Own Sweet Potatoes at Home

What do you call roots that say things like, “You're the best”?

Sweet potatoes.

If you're looking for someone who has really bad vegetable garden puns, I yam here for you. 

Okay, okay, I know. They're so bad, but I just can't help it with these dumb puns. Because you know what? I yam who I yam. 

We're actually not talking about yams today. We're talking about sweet potatoes, and believe it or not, sweet potatoes are different from yams. 

Sweet Potato vs Yam

I thought these were the same thing for a long time, but it turns out, yams and sweet potatoes are two different plants from two different plant families, and they even look different. Things they don't tell you at the grocery store...

Sweet potatoes are herbaceous vines often grown as annuals, and they're mostly cultivated in tropical regions for their starchy tubers.

Yams can be perennial in tropical regions, meaning they can go on and on and live for years. Yams have a rougher outside (more bark) and a more earthy flavor, while sweet potatoes are soft and sweet. The inside of sweet potatoes, the flesh, is orange in color, while yam flesh is typically white.

You know those candied yams sold at the store around the holidays? Yeah, those are sweet potatoes. If you live in the US, it's likely you've never actually had a yam.

(Prefer to listen? Check out "Sweet! The Surprising Story of Sweet Potatoes" on the Grow Your Self podcast on iTunes, Spotify, Stitcher, or iHeartRadio.)

What Are the Health Benefits of Eating Sweet Potatoes?

Here are five reasons why you should absolutely be filling up on the good stuff—sweet potatoes:

Sweet potatoes are highly nutritious

They're a great source of fiber, vitamins, and minerals. Just one cup, 200g, of baked sweet potatoes provides you with tons of vitamins and nutrients, including 4g of protein, 769 percent of your daily value recommendation for vitamin A, 65 percent of your recommended vitamin C, 29 percent of vitamin B6, and 27 percent of potassium.

Sweet potatoes are good for your gut health

You get lots of fiber and antioxidants in sweet potatoes, and both are proven to help with digestion. Sweet potatoes actually include two kinds of fiber, soluble and insoluble. Your body can't digest either of those types. Do you know what that means? They stay in your body longer, help you feel full longer, and help you go number two.  

Sweet potatoes are loaded with cancer-fighting properties

Sweet potatoes have lots of antioxidants, which studies have shown can help reduce the risk or spread of cancer. They also help increase the body's power to fight cancer for those who already have it. Both the flesh and the peel have these anti-cancer properties.

Purple sweet potatoes especially contain anthocyanins, a group of antioxidants, so look for purple sweet potatoes next time you're at the farmers' market. In studies, mice fed a diet rich in purple sweet potatoes experienced lower rates of early-stage colon cancer.

Anthocyanins also protect your brain by reducing inflammation and preventing free radical damage.

Sweet potatoes are rich in beta carotene

The antioxidant responsible for giving sweet potatoes that orange color also helps you see better. Eating just one cup of baked sweet potato with the skin gives you seven times the beta carotene that you need per day. Beta carotene is converted to vitamin A in your body, and that turns into light-detecting sensors.

Sweet potatoes build a strong immune system

We all need a good immune system now. The beta carotene in sweet potatoes helps increase your body's immunity.

The Sweet Potato Origin Story

Sweet potatoes have provided hints that there may have been travel from Asia over to South America before "Columbus sailed the ocean blue" and all those European explorers claimed to have discovered "the New World."

Sweet potatoes are from Central and South America, where they were consumed for over 5,000 years to support the nutrition and growth of populations there. But there's evidencee that sweet potatoes were being grown in the Cook Islands, in the area of Polynesia, all the way back to 1000 A.D., and possibly even earlier. Archeologists are trying to figure out if Polynesians could have sailed across the Pacific in their double-hulled canoes, all the way from Polynesia to South America, gotten the sweet potato root, and brought it back. 

The Polynesian word for sweet potato is kuumala, which resembles kumara or cumal, the Quechua words for sweet potato. It’s crazy to think that exchange might have happened over a thousand years ago.

Columbus encountered sweet potatoes when he was in the West Indies and the Yucatan. He recorded it in his journals after his trip to Honduras and is credited—whether it's true or not—with this tuber's introduction to Spain in about 1500. 

If you think about it, sweet potatoes began in Central and South America, where the climate is super different than it is in Europe, so its popularity was slow to spread across Europe. You really need warmer temperatures to grow sweet potatoes. 

Sweet potatoes finally took off with European settlers in North America. They're noted as being grown in Virginia in 1648. Native Americans were growing their own sweet potatoes by the 1700s. 

Even today, sweet potatoes grow better and are much more popular in the southern part of the U.S. than they are in the North. Whenever I visit my home state of Mississippi in August, my mom and dad have a big box of sweet potatoes that they've just bought from local farmers and will keep all through the fall and winter. 

Fun fact: George Washington Carver, the Black agricultural scientist from Missouri who's known for his work with peanuts, also did tons of work with sweet potatoes. In fact, he's credited with developing over 125 diverse products with sweet potatoes, including dyes, wood fillers, candies, paste, breakfast foods, starches, flours, and molasses.

Where Sweet Potatoes Grow Best

Sweet potatoes are very common in Asian cultures, perhaps from that first exchange back in 1000 A.D., but they really haven't caught on yet a ton in the Western diet. Most nutritionists and health experts say, “Hello, why are we not eating more sweet potatoes? They’re so good for you, not that expensive, and easy to store. We should all have sweet potatoes as part of our regular diet." 

Sweet potatoes are grown mostly in North Carolina, California, Mississippi, Texas, and Louisiana in the U.S. Again, the sweet potato is a warm-weather vegetable, and it can even be grown year round in parts of the South where there's no frost. When I lived in Houston, Texas, I loved growing sweet potatoes over the hot summers.

If you live somewhere with a long warm or hot season, you should absolutely try growing your own. If you don't want to grow your own but want to enjoy sweet potatoes at their peak flavor and nutritional content, buy them in season from the farmers' market. You won't get the same quality if they've been shipped/imported as you do when they're grown right outside your door.

Are Sweet Potato Leaves Edible?

Here's a fun fact: When you grow your own, you can enjoy the entire plant, not just the tuberous roots. Sweet potato leaves are edible and so good for you. Specifically, these greens are filled with vitamin C.

How Sweet Potatoes Grow

When I was taking plant family photos for my first book, Kitchen Garden Revival, I realized sweet potatoes would be the only ones in the picture for the Convolvulaceae family, more commonly known as the morning glory family. While there are a ton of species in that plant family, most are just herbaceous. Very few of them are things we would grow to eat. 

We ended up not putting that photo in the book because it just looked awkward, which is a great indication that sweet potatoes are in a league of their own. They're not going to be grown like most other plants in the kitchen garden. 

Sweet potatoes are tuberous roots that produce underground and above-ground stems. More tubers form at the edge of each of these stems.

Let's take a look at how to grow your own sweet potatoes.

How to Grow Your Own Sweet Potato Plant

Growing sweet potatoes is a different experience from many other plants in the garden. You're not going to order a little seed package or a seed potato, like you would with a potato in the Solanaceae family. You're actually going to grow sweet potatoes from a slip. (Not the kind of slip you'd wear under a thin dress.)

A slip is actually a little shoot, a little green growth that grows off of a mature sweet potato. If you've seen pictures or videos on social media of sweet potatoes growing in jars, those are slips. One sweet potato could actually produce up to 50 slip sprouts. You can buy sweet potato slips online or grow your own from organic store-bought potatoes.

Here's a fun little experiment to do with your kids: Stick some toothpicks through a sweet potato and suspend the bottom portion (the tip that's more tapered, less rounded) in a jar of water. Keep your jar somewhere warm and give it some light. Over the next couple of weeks, roots will form from the bottom part, and sprouts will emerge from the top. Refresh the water in the jar every couple of days.

Even if it's not time to plant sweet potatoes (it's not the right time in most places in North America right now), you can eat the sweet potato greens and watch the magic of food growing.

Another way to grow slips is to place a mature sweet potato in moist compost in a cool and dark place. Within a few days, you should see shoots of little green growth. (You've probably inadvertently grown some slips in a pantry if you've ever kept sweet potatoes too long.)

If it is almost time to grow sweet potatoes, then start your slips about 6 weeks before planting time. Remove slips from the sweet potato by cutting them at the base when they're about 5 to 6 inches long. Let the slips root in a jar of water. You should notice roots forming within 48 hours. Throw out any wilted or rotten slips, and continue to refresh the water in the jar. Your slips are ready for planting when their roots are several inches long.

Sweet Potato Growing Season

You might associate eating sweet potatoes with cold weather, but these plants actually need heat to grow—the hotter, the better!

You only want to plant sweet potatoes after all chance of frost has passed. Even in Houston, which is a warm climate that typically experiences little frost, my clients wait until late April or early May to plant their sweet potato slips. Sweet potato plants are not frost-hardy at all.

If you have really hot summers, sweet potatoes are a great plant to try. They're one of the few plants that grow during the hot season that can handle a little neglect. We like to grow these for clients if they're traveling during the summer or just don't want to work out in the heat and humidity. 

Even if you can't give sweet potatoes 100-degree heat like Houston gardeners can, look for at least 100 days where the weather will be above 80 degrees—that's your sweet potato growing time.

How to Plant Sweet Potato Slips

Once you've purchased sweet potato slips or grown your own—and once your last frost date has passed—it's time to plant your sweet potato slips.

You can grow sweet potatoes in raised beds, but it's best to dedicate the entire bed to sweet potatoes since those vines will take over. Make sure the planting spot you've selected gets eight or more hours of sunlight per day. Sweet potatoes will soak up every minute of sun you give them, even when it’s hot outside.

Prepare your planting area by digging down about 12 inches to loosen the soil and adding compost to the soil. This ensures there will be enough nutrients for your tubers to work their underground magic.

Plant sweet potato slips in rows that are at least 18 inches apart. You can fit about 12 sweet potato plants in a 4ft. x 6ft. raised bed. That's one plant every 2 square feet in a 24-square-foot space. That would be a little tight if you were growing in the ground, but this spacing works in raised beds because the roots have more space to spread down, and the plant has space to grow up instead of growing wide. These vines need space to run.

You'll see pretty quickly that the sweet potato leaves take over. Your beds will look completely wild by the middle of the summer, but one of the great things is all that wildness is great for your soil health. Sweet potatoes are fantastic soil coverage because of all the green that grows from just a few slips.

Sweet potatoes are also drought-tolerant. That's another great reason to grow them in hot places. Those vines will protect your soil and not demand a ton of water, but you will definitely get more production if your plants receive at least one inch of water a week.  

How to Care for Growing Sweet Potato Vines

Sweet potato plants typically don't experience pest issues. You might get aphids, flies, or other bugs on the leaves. I once had grubs in the soil that attacked the roots below the tubers a bit.

There are diseases like black rot and stem rot that can affect sweet potato vines. To prevent disease, grow your plants in a nice, healthy soil and avoid overwatering. Soil really matters here because so much of the growth happens underground. Without healthy soil, you might see a lot of green growth above ground, only to find poor tuber root growth once you dig in.

If you're worried about disease in your soil, consider solarizing it before you plant sweet potatoes by laying plastic sheeting or a tarp over the soil for 6 to 8 weeks.

Continue to give your sweet potato plants about 1 inch of water a week.

When Are Sweet Potatoes Ready for Harvest?

Some sweet potato varieties say they're ready to harvest in 90 days, but I typically grow up for 120 days or more. In my experience, 90 days is not enough time for these plants to grow big roots. In Houston, I would plant sweet potato slips in May and harvest tubers in late September or October.

So, mark you calendars about 4 months after planting for sweet potato harvest time. Yellowing leaves are another clue that our tubers are ready to be harvested.

A couple of days before harvesting your sweet potatoes, cut the vines above the soil to send the plant’s energy toward toughening up the roots, hardening the skin, and sweetening the tubers. Hardening the skin is important so you don't peel off the skin accidentally during harvest.

To harvest, use your hands to dig around the tubers. Their skins are very delicate and can be easily damaged.

If your soil is healthy, you can leave some sweet potatoes down in the ground and harvest them as you go. We've had clients who harvest some and then wait all the way until Thanksgiving to harvest a few more (that's only for areas that don't get frost in November).

How many sweet potatoes can you harvest from each plant?

One hill of a sweet potato plant could yield about two pounds of sweet potatoes if the conditions have been just right.

Next time you're at the grocery store, weigh out two pounds of sweet potatoes to get a better idea of how much each slip can produce. I think we overestimate potential production from edible plants. We forget how much space is actually needed to grow our food. 

How to Cure Sweet Potatoes

After harvesting sweet potatoes, you’ll need to cure them before enjoying them. Set them in a warm place in your home, such as near a heater, and let them rest for a few days before you eat them. Curing allows the tuber to settle its sugar content and brighten the flesh. 

Out of the ground, sweet potatoes can be stored for six to ten months. You do want to store sweet potatoes somewhere that stays about 55 to 65 degrees, but they don't have to be stored in the refrigerator. Spread them out to make sure they're not rubbing against one another and avoid wet areas, and you'll end up having sweet potatoes for a long, long time.

How to Enjoy Your Sweet Potatoes

One of the best things about sweet potatoes is how long they store. That means sweet potatoes are still in season in the winter, when we crave warm, nutritious meals. Every Thanksgiving, my mom makes the best sweet potato casserole. One half has marshmallows on top, and the other half has this amazing pecan candy thing. Many of us have sweet potatoes around the holidays because they grow during the hottest months and then save well into the winter.

If you're looking to get the most out of a plant and have something that stores and can carry you through the winter, this is how Native Americans kept their civilizations alive for 5,000 years. They would grow sweet potatoes, store them, and eat them nearly year round. These kinds of foods should really form the base of our diet because they don't require a ton of shipping, storage, or refrigeration, and they last so long.

Not only are sweet potatoes so good for our bodies, it's good for the environment to focus our diets more around foods like this.

If you're a smoothie fan, which I definitely am, you may often find yourself using something like bananas a little too often in your smoothie mix. If you're trying to eat local and more seasonal but you're not in a tropical region, bananas are neither local nor seasonal. It's hard to make a smoothie with some sweetness in it and some creaminess and still be local, but sweet potatoes can make that possible. You just cook the sweet potatoes and let them cool. You can even cut them up into cubes, freeze them, and then blend them up in your smoothie. It's going to give you a sweetness to your smoothie and you can call that more seasonal and local than if you're using bananas.

If you're looking for more sweet potato recipe ideas, check out the book Sweet Potatoes: Roasted, Loaded, Fried, and Made Into Pie: A Cookbook by Mary-Francis Heck.

Sweet Potato vs Regular Potato 

I love to compare the nutritional value of foods that we often think of as similar in the garden and in the kitchen. Let's do a match between the two tubers: sweet potatoes and regular ol' spuds like russet potatoes. Who do you think is going to win?

Round #1: Sweet Potato vs. Regular Potato Nutrition

The numbers I give are for 100g of each tuber.

Sweet potatoes have 14,187 IU of vitamin A, which is more than 300 percent of your daily value, while potatoes have 2 IU. There are 4.18g of sugar in a sweet potato, but only 0.82g in a regular potato. Sweet potatoes have 0.8mg of vitamin B5, while potatoes have just 0.295mg. Sweet potatoes also have one more gram of fiber. Vitamin C surprised me: potatoes win here, with 19.7mg of Vitamin C, compared to just 3.2mg for sweet potatoes.

When it comes to other minerals, potatoes win in most categories. Potatoes have 32 percent more iron, 26 percent more potassium, 36 percent more folate, and 21 percent more phosphorus. Sweet potatoes do have 150 percent more calcium though.

So plain potatoes are obviously lower on the glycemic index (they also have less sodium and fewer calories), but the vitamins and minerals available in each are just about tying them for Round 1.

Round #2: Sweet Potato vs. Regular Potato Growing

I've had more success growing regular potatoes than sweet potatoes. Regular potatoes are more predictable in that they grow up into a containable bush-like plant, whereas sweet potatoes vines can grow wild. Potatoes are also really easy to grow in the ground because they're not picky about the soil.

That being said, sweet potatoes are one of the easiest plants to grow if you live somewhere with a hot season, during which time not many other plants will grow well. If you live in Florida, Arizona, Texas, Louisiana, Mississippi, Alabama, etc., sweet potatoes are a wonderful thing to grow during the summer.

Flavor-wise, I prefer the taste of sweet potatoes, though homegrown potatoes are incredible.

I'll let you call this one. Which tuber is the winner?

Enjoy Your Homegrown Sweet Potato Harvest!

I hope you feel inspired to buy sweet potatoes from your local farmers or CSA, to try growing your own, and to fill up on the good stuff while it's in season.

Before you go: What did the potato say to the yam?

Any idea?

She said, “Boy, you sure are sweet!” And I'm sure she would say that to the sweet potato too, if she knew that sweet potatoes were different from yams.

What can I say? Potato puns just a-peel to me!

Thanks for being here! I hope you fill up on the good stuff and eat lots of sweet potatoes all winter long.