Home gardeners quite like growing their own sweet potatoes, especially ones in containers. They are confined to one space, and you can grow them almost anywhere.
The great thing about growing sweet potatoes in containers is that you don’t really have a danger of frost because if the climate changes and its starting to get cold, simply move the container indoors where it’s warmer.
You might need to add a grow light to act as the sun, but it is easily possible.
Let’s quickly get the tech part out of the way. Sweet potatoes are tuberous roots and are different to yams in their genetic makeup – sweet potatoes are actually a member of the Morning Glory family, while true yams are from the Lily family. This means that sweet potatoes typically grow shorter vines and have smaller leaves than yams.
Huh. Who knew? Doesn’t that make any difference in your life? Probably not.
Sweet potato colors vary; you can grow white flesh, orange flesh, and purple flesh. The color of the sweet potato doesn’t affect the taste, but it can be a fun way to add some variety to your dishes.
Sweet potatoes are not tubers, like potatoes are. They are roots. If you leave them, they will keep growing and growing until the first frost.
Before you get started, know that sweet potatoes have a long growing season. But, the crunchy, yummy sweet potato fries will be well worth it!
Ideal planting season: Spring
Container: 20 – 25 gallons are best
Sun: Full sun
Soil temperature: Over 65 F during the day, and that nighttime temperatures do not drop below 55 F (generally 3 – 4 weeks after the last frost)
pH level: 5.5 – 6.5
Latin name: Ipomoea batatas
Planting slips to grow sweet potatoes
Sweet potatoes are grown from a thing called a ‘slip,’ which you grow yourself! (don’t you love growing your own food? It gets cheaper and cheaper!)
Plus, slips are super easy to grow, and once they’ve grown, you just cut them off the main potato. In fact, if you ignore your potato, chances are it will start to grow leaves and a stem (in other words it will grow the slips), without you lifting a finger.
Let’s begin.
The first thing you need is a sweet potato. Nothing fancy, you can get one from your local grocery store and from this you’ll need to grow slips.
A sweet potato slip is a stem and leaves grown from a sweet potato, which then develops roots. This is one of the easiest ways to start growing your sweet potato plants.
Note: If you’re planning to get your plants in the ground in spring, you’ll need to start growing the slips around 4 – 6 weeks prior, to allow the slips to grow long enough.
The method to grow your own slips
Take a sweet potato and cut the two ends off. You’ll see around the internet and on YouTube that some people try and grow slips from an entire sweet potato, but that isn’t necessary.
Take the two ends and place them cut side down in a container and fill it about an inch of water, with water. Leave it in a sunny spot and let nature do its thing.
When the slips are around 10 inches long, snip them off at the base of the slip as close to the potato as you can, and place these slips into a glass of water. You’re now going to grow roots from the bottom end.
- The new roots will take a couple of weeks to grow
- Each nodule on the slip will grow roots
- Watch for algae growth and clean your container or change your container as the algae can kill your slip
To plant sweet potato slips, simply bury them in the ground about 6-8 inches deep. Be sure to water regularly and provide plenty of sunshine. Within a few weeks, you should see new leaves starting to sprout.
The above instructions is what you’ll read pretty much everywhere.
But – here’s what I did.
I left the sweet potatoes alone for ages. Weeks, in fact. They grew the slips (image on the left) and I left them. I didn’t plant them in water, I didn’t do anything. I didn’t even put them outside.
They were indoors, in the pantry area that has a normal light on more often than not.
When the potato looked like it was starting to dry out, I cut the slips off, and put them in a jar of clean, tap water.
IT TOOK TWO DAYS FOR THE ROOTS TO GROW!!
That’s it – only two days! (and that’s the image on the right).
I had another sweet potato growing slips so I decided to conduct an experiment.
1. I cut two slips off one potato and grew the roots in two days.
2. I took the rest of the potato still with smaller slips and placed it, as is, in water. Roots started growing from the potato within two days.
3. I took the second potato which also had slips growing, I didn’t put it in water, and I planted it directly into the soil
This was in December 2022. I will update this post later when I have updates.
Using the cover up method to grow sweet potatoes
The cover up method is another popular way to grow sweet potatoes (mentioned above in point three).
It involves placing a sweet potato in a container of soil and then covering it with soil. The container can be anything from a pot to a bucket, to a grow bag.
The key is to make sure that the sweet potato is completely covered with soil with the stem and leaves emerging.
As the stem grows, keep covering it and water regularly.
Keep the soil moist but not wet.
You can also use hay or straw or even bark chips as mulch.
With a little care, you can enjoy a bountiful crop of delicious sweet potatoes.
Best container tips when growing sweet potatoes
- As I’ve said before, one of the most important things to successful plant growing is having the best soil, get this right from the beginning and you’re halfway there. Check the soil by carrying out a soil test. Make sure that the pH levels are between 5.5 – 6.5. Check this in advance so if you need to make adjustments to the soil, you’ll have time to do so.
- Sweet potatoes do best in a large container with plenty of room for their roots to spread. Look for a 20 – 25 gallon grow bag, bucket or even a large plastic storage container. Remember that sweet potatoes grow downwards, so it has to be deep.
- The container must have drainage holes to allow excess water to drain through quickly. Sweet potato plants must not be allowed to set in very damp soil.
- Whichever container you choose, be sure to fill it with loose, well-drained sandy loam soil. The pH levels should be between acidic and neutral.
- Sweet potatoes need plenty of water, so be sure to check the soil regularly and water as needed. With a little care, you can successfully grow sweet potatoes in just about any container.
Water regularly
Watering sweet potatoes grown in containers regularly is important to their health and yield.
The water schedule for sweet potatoes grown in containers depends on the size of the container, the type of soil, the weather, and how often you water.
A general rule of thumb is to water sweet potatoes grown in containers every 7-10 days but don’t drown them. Just keep the soil moist.
Best way to feed sweet potato plants
Sweet potatoes are pretty happy in good quality soil, and don’t really need special fertilizers.
What you could do though, is add an organic product such as vermicastings or ‘worm poo,’ which is an excellent, natural source of nutrients for plants. This helps to improve the soil health, and promote plant growth.
Best companion plants for sweet potatoes
Sweet potato plants and peas and beans can be planted together in a companion planting method known as the “Three Sisters” method.
This method is based on the traditional agricultural practices of indigenous people in North America, where corn, beans and squash were planted together.
1. The corn provides a structure for the beans to climb
2. The beans fix nitrogen in the soil which benefits the other plants
3. The squash provides a living mulch that helps to retain moisture and suppress weeds
In this method, sweet potatoes can be planted as the “ground cover” crop and grown alongside beans and peas. The sweet potatoes act as a living mulch, helping to suppress weeds, retain moisture and provide a natural source of fertilizer. The beans and peas will also benefit the sweet potatoes by fixing nitrogen in the soil, which will make the soil more fertile for the sweet potatoes. This can lead to increased yield and healthier plants.
When to harvest your home-grown sweet potatoes
In some states and parts of the world, the ends of the vines will turn a brown color and you will know it is time to harvest your sweet potatoes. Other states and countries closer to the equator where it’s warmer will not give you clues.
Just remember this rule, if your plants are outside, you need to harvest before the first frost. If you wake up one morning and find that the leaves have frosted, just mow them down immediately and then you have about a week to dig them up.
In general, wait about 4 – 5 months before attempting to harvest your sweet potatoes.
The first light frost is unlikely to damage your sweet potatoes, but it means you’ve got work to do as you’ll need to get them up before the heavy frosts begin.
How to harvest your sweet potato plants
If your sandy soil, or loose soil, you can just get your hands in the dirt and carefully dig around the plant to find them. Once you’ve found them, you can simply break them off from the roots. If you want to, you can use a sharp knife or gardening shears to clip them free. Be sure to leave at least one or two sprouts on the root so it can continue growing.
If your soil is more dense, you can use a shovel or a garden fork. Carefully stick it into the ground and then just pop the soil upwards to loosen it. Then get right down there and stat digging around with your hands.
if you come across some that are still small, just pop them back in the ground, cover them up and leave them to continue growing.
The greenery of the leaves and vines make excellent ground cover, but if you need to start clearing it away to prep for your fall crops, that is possible.
Select plants that grow taller such as peas, which are also great companion plants as they fix the soil with nitrogen, something that sweet potatoes need to live and thrive.
Peas are also great companion plants because they fix the soil with nitrogen, something that sweet potatoes need to live and thrive.
Sweet potato vines and leaves
Sweet potato leaves are completely edible. When’re ready to harvest your ‘taters, it’s time to start collecting the vine cuttings and them in bunches.
If you’re looking for a delicious way to use up your sweet potato leaves, why not try some Vietnamese or South African dishes? Both countries have a variety of dishes that include sweet potato leaves as an ingredient.
For Vietnamese dishes, you can try stir-frying the leaves with pork, shrimp, or chicken. Or, you could add them to a soup or salad.
South African dishes often include a stew or curry with sweet potatoes and other vegetables. The leaves are typically chopped up and added to the dish near the end of cooking.
You’ve harvested your sweet potatoes. Now what?
Curing Your Sweet Potatoes
Next, you’ll want to leave your sweet potatoes in a humid space to cure. Curing the sweet potatoes helps them to last longer and keeps their flavor and sugar content consistent aka sweet.
You can do this in a greenhouse or a similar warm room. The temperature needs to be around 80 – 85 degrees F (26 – 30 degrees Celcius) in really, really high humidity.
A nifty little trick is to cover them in a thick blanket to trap in the heat that is evaporating and creates humidity.
Too much heat will cook them. Frost will kill them.
If frost does get them, just toss them on the compost heat.
If you don’t take the time to cure them, they will not have a sweet taste; in other words, they’ll be starchy.
A humid space can be an enclosed room, a greenhouse, or even just a shady spot outdoors and they should be left there for about 10 – 14 days.
Once curing is complete, move the harvested sweet potatoes to a cool, dry place until you’re ready to use them. If you want them to last longer, wrap them in newspaper.
If you store them correctly, the shelf life can be as long as 6 months. #happydays
Pests and Problems
As with all plants, there are some pests and problems you need to look out for, but doing regular checks on your plants so enable you to pick up anything quickly.
One way to organically protect your plants is to grow some companion plants that are suitable, with your sweet potatoes.
The most common diseases with sweet potatoes are:
- Root-knot nematodes
- Sweet potato weevils
- Fusarium wilt
To try and avoid these, select disease-resistant varieties and make sure you are planting disease-free slips right from the start.
And that’s it!
After about 4 – 5 months, your sweet potatoes are ready to be enjoyed!
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Happy planting!
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