How to Grow Sweet Potatoes

how to grow sweet potatoes

It’s no surprise that growing sweet potatoes is so popular with their long-storied history. Whether it be their origins placing them in Peru or Columbus bringing them to Europe during his famous tour of the America’s, sweet potatoes have always held a special place in the gardens of the people who’ve grown them. Their sweet flavor and high yield have contributed to their success and are a massive benefit for one’s gardening ventures. Keep reading to learn how to grow sweet potatoes.

The process for the growth of sweet potatoes is simple and requires few steps. Begin by planting the slips 12-18 inches apart during the early stages of spring with above a 60 degree Fahrenheit soil temperature. Water the plants regularly about one inch until two weeks before harvest. Finally, dig up the potatoes and cure them to store for at most six months.

While in the abstract this process seems fairly simple the main difficulties come from the development and cultivation of the sweet potatoes’ growth. As the environment they are most optimal for is one of the warm temperatures and high humidity, sweet potatoes require specific nuances and steps to develop. Don’t worry despite these nuances once properly handled sweet potatoes are as easy as learning to follow any baking recipe and coincidentally perfect for one as well.

growing sweet potatoes

Growing Sweet Potatoes

Pre-planting

The main nuances of growing sweet potatoes actually come completely before even the planting takes place due to, as stated before, their very specific environment required for growth. The interesting part is with a little work and necessary equipment you can work to match this environment to allow for easy growth and harvesting.

Slips

A large contribution to proper growth is having an actual plant to grow from and this is where the slips come into play. Slips are rooted sprouts from mature potatoes and are one of the only ways to grow sweet potatoes as almost all grocery stores shave their potatoes down to prevent growth. The upside to this is that slips possess a very efficient growth rate once placed in the proper soil.

Soil Temperature

Soil temperature is the main consideration in these slips growth as sweet potatoes require a warm temperature. Specifically, a range of about 60-75 degrees Fahrenheit to allow for a normal growth rate and harvesting period. Generally, this temperature is more likely to occur after the last spring frost. Although, an alternative method to increase the temperature of the soil is the use of black plastic in mulch but black plastic containers work just as good if mulch is unavailable.

Spacing

Speaking of containers, it’s good to note that the spacing in these containers is an important aspect of sweet potatoes' continued intake of nutrients. On average, you’re going to want to be spacing out your sweet potatoes 12-18 inches apart to allow for the roots to properly grow and expand. Though this will change depending on the type of sweet potato being used but I’ll get into more detail on that later.

All of these items and considerations are important when aiming for the maximization of growth and yield for sweet potatoes. They should also allow a smooth transition from planting into the growth phase of gardening.

Growth and Development During Season

So, you’ve done a lot of the heavy lifting during pre-planting. Overall, that is going to allow much easier growth from here on out but there are a few critical steps that need to be taken to maintain this progression throughout the rest of growth. A lot of the steps from here on out are focusing on mainly the protection of the plant to prevent disease or any other significant problem from consuming our yield.

Garden Fabric

Once the slips have been carefully planted, you’re going to want to surround the entire growing area, except for the potatoes of course, in garden fabric. The fabric will help to reduce a lot of the stress that is being put on the slips by early growth and decrease weeds in the garden. The fabric should only be needed for the first 3-4 weeks of growth. It can be removed after that to allow maturity to take place, but no change is required in gardening so regular watering is still needed.

Watering

Watering for sweet potatoes is overall fairly similar to any other vegetable. Sweet potatoes require about 1 ½ inches of water a day with a total of one foot of water per three weeks. You want to make sure to water the soil around the plant to reach the roots underneath and allow steady growth. You’re going to want to slow down watering about two weeks before harvest to allow the soil to dry out for easy removal.

I would also recommend supplementing the watering with a starter solution high in phosphorus after planting as this gives the young slip a steady growth. Phosphorus is critical in the early development of plants as it acts as a base for a lot of what happens in photosynthesis and acquiring energy. Though, it’s only necessary for the early stages of growth as it will begin acquiring a source of phosphorus from our next step, side-dressing.

fertilizer

Fertilizer

After 3-4 weeks of planting the slips, about the same time you remove the garden fabric, you’re going to need to begin side-dressing the potatoes with fertilizer. Your fertilizer for maximum growth should contain 5% nitrogen, 10% phosphate, and 10% potash. The bag will simply state 5-10-10 so make sure to keep an eye out for that. For every 100 feet of row, you’re going to want to use 3 pounds of fertilizer unless using sandy soil then you’re going to need about 5 pounds. All that’s required once acquiring the materials is to place the fertilizer along the side of the sweet potatoes’ row.

Maintenance

The early development is now finished so the rest of the growing period simply requires regular maintenance. All of the maintenance is fairly cliché for the growth of any vegetable. You’re going to need to hoe the bed occasionally after removing the garden fabric to prevent the weeds from draining nutrients from the potatoes. The only step unique to the sweet potatoes is the lifting of the roots on occasion to prevent them from rooting at the joints to maintain a controlled growth.

Overall, we’ve front-loaded a lot of the work to allow for easy and substantial yield once we’re ready for harvest but after you’ve done those beginning steps it's smooth sailing for a big harvest. Harvesting that should be made significantly easier by that early work we’ve put into our sweet potatoes.

Harvesting

You’ve finally reached the moment that all this hard work has been leading up to but there are still a few steps before you can begin cooking up some tasty sweet potato pie. Beginning with identification, it’s important to begin paying more attention to your sweet potatoes leaves and vines around the 100-day mark. The more yellow your leaves and vines look the more likely they are ready for harvest. You want to keep them out just long enough so that they're fully ready with the maximum yield and vitamin content but not too long as to allow disease or animals to overtake your sweet potatoes.

Removal

The potatoes are ripe for harvest, but you need to be sure that your removal is careful. I suggest the use of a spading fork to dig around the potatoes due to the length of the mature roots. It’s smart to also loosen the soil around the plant to prevent any damage from actually occurring as that can cause early spoilage and prevent proper curing from taking place. This is why it’s important to begin slowly decreasing the amount of watering you're doing before the harvest as it dries out the soil for easy removal.

The dirt should now be loosened enough to allow you to easily remove the sweet potatoes by the primary crown of the plant. You want to guarantee that you’re not pulling or applying too much pressure to the newly harvested potatoes as that can cause bruising. This may require you to have to dig around the roots more but it’s more important to be overly cautious than be stuck with ruined potatoes.

Cleaning

Now that you’ve got some strong healthy potatoes, you’re going to want to clean them before allowing the curing process to occur. When cleaning a sweet potato, you want to make sure to carefully shake off any excess dirt but there’s no need to remove all the dirt in every crevice. Water can’t be used for cleaning as the roots cannot be made wet after removing from the soil. After the dirt has been removed you want to allow the sweet potatoes to air dry for several hours to remove any excess moisture before curing.

Curing

We’ve finally reached the moment that we’ve all waited for, the final step required for sweet potatoes, curing. Please note, this is also one of the most critical as curing allows the potatoes to maintain and intensify their sweet flavor for several months. You’re going to need an area that is both warm but also high in humidity for about 10 to 14 days. Depending on your location, you could simply place these on a table in the shade or perhaps an attic. The main goal is wherever that is easily accessible and fits the requirements for curing. Once you’ve selected a location you can store the potatoes there but remember to keep the potatoes separated from touching one another.

The potatoes after curing should last up to six months as long as they’re stored in a temperature range of 55-60 degrees Fahrenheit in high humidity. They are now fit for whatever recipe you’ve been craving or even a simple bake. I promise no sweet potatoes are as good as the ones you’ve harvested yourself so go ahead and dig in.

sweet potato varieties

Sweet Potato Varieties

Due to sweet potatoes' ease of growth and popularity all around the world, sweet potatoes have produced many varieties that are genetically distinct from the classic American style. Honestly, there’s too many for this one article but I’ve taken the time to list a few common varieties that possess notable deviations from the original that you may find useful.

Beaureguard

Beginning with a fairly common variety, Beaureguard possesses a purplish-red exterior and light orange interior, the one most commonly associated with sweet potatoes. The main difference between this variety is its substantially larger yield in comparison to the common sweet potato. It’s also quite disease tolerant so overall it makes it pretty good for beginners as no matter what you’ll most likely obtain a harvest. The main drawback comes from its exceptionally larger roots so you’re going to need to expand your plot in comparison to a normal sweet potato.

Georgia Jet

Speaking of larger roots, the Georgia Jet is another variety that will require a larger plot but is good for cooler areas. This means if you’re living farther north it might be a safer bet to use Georgia Jet slips as they’re more likely to actually grow without heavy maintenance. The harvest period is also a bit shorter, clocking in at about 90 days instead of the normal 100.

Jewel

Perhaps you have a larger amount of time on your hands though so you can handle a longer harvest period. If so, I suggest the Jewel. It’s a variety of sweet potato that is considered one of the most flavorful varieties despite its short chunky appearance. The Jewel also possesses an extremely high yield with one plant producing about six sweet potatoes on average. Though as mentioned earlier, it does have a longer time until the actual harvest at about 120-135 days from planting but is absolutely worth the wait.

Buncho Porto Rico

Maybe you’d prefer a simpler variety though, one that requires a bit less work and room. If so then I’d suggest the Buncho Porto Rico variety of sweet potatoes. While the harvesting time for these potatoes is the same as normal sweet potatoes, Buncho Porto Ricos possess shorter roots. This means that your gardening area and rows can be much smaller for them. Overall, if you end up using this variety, you’d need fewer materials and less maintenance due to the size making it easier to grow. It’s also described as having an old-fashioned taste very good for baking so that could be another plus depending on what you want your sweet potatoes for.

In the end with so many varieties, I promise there’s going to be sweet potato that’s right for you and your situation. I’ve been able to go over a few that solve some of the common issues associated with growing sweet potatoes or improve upon them but there are plenty more. If I didn’t list one that exactly fits what you’re looking for go ahead and search for more varieties. All of them can be found and ordered online with a few simple searches but don’t forget the steps for growing potatoes are all the same and can be found right here.

Common Problems & Remedies

All the steps and recommendations I’ve listed have been to prevent any issues from happening so my first suggestion is to try your best to stick to those tips. Just remember, growing sweet potatoes is a long process and despite your best efforts, problems can occur but if you can catch them early, they can be handled. This section's goal is to list some common issues that can happen, especially if your sweet potatoes haven’t been properly maintained, and how to solve them.

stem rot on potato

Stem Rot

Firstly, I want to begin with one that’s most likely to take place due to improper handling of your slips as that’s probably going to be the first thing you acquire, stem rot. Stem rot occurs if the slips have been damaged and allowed fungus to enter the plant from insects, wind, or careless cultivation. A simple solution is to make sure your planting healthy slips and being careful with them if so that should minimize any risks but if needed they do have resistant cultivars. In case you don’t know what cultivars are, they are carefully bred plants meant to gain specific traits like disease resistance.

Black Rot

On the topic of fungal diseases, another common one is black rot. It’s caused by practically the same scenario but can in the end be much more devastating to a plant’s overall growth. The main treatment after noticing its effects is to try and remove the infected potatoes. You’re also going to want to carefully cure, essentially relocate away, the undamaged roots from that same crop to prevent spreading.

Sweet Potato Weevils

The main contributors to the fungal rot are insects and the ones most devastating to sweet potatoes are the sweet potato weevils. Sweet potato weevils are a common insect, ¼-inch-long insects with dark blue heads/wings and red-orange bodies, that can be devastating to a sweet potato harvest. They are naturally drawn to the plants as that’s where they prefer to lay their larvae and can completely destroy an entire garden of sweet potatoes. The easiest solution to deter infestation is by the prevention of soil cracking. Regular soil irrigation or the hilling of a small area around the sweet potato to keep the insects away from the roots are the strongest solutions.

Protection for your garden is always going primarily be maintenance and cultivation so at the end of the day focus on that as your main source. I suggest keeping a careful watch over your garden and noting any changes that occur on a regular basis. If something looks unhealthy on the plant it most likely is, so go ahead identify the issue and its solutions. All problems can be prevented if caught early enough and, in the end, cause minimal damage to your plants. The best prescription is careful cultivation but if that doesn’t work damage control is a strong second option.

growing sweet potatoes

Related Questions

Growing sweet potatoes is a long process and requires a lot of effort so naturally, questions are going to occur no matter what stage you're in. In an effort to allow this article to act as a comprehensive guide I’ve added some common questions that I’ve seen during my research.

How long does it take to grow sweet potatoes?

The answer is it honestly depends on the variety. On average it’s going to take a sweet potato about 70 days to as long as 170 depending on the variety till harvest. A good rule of thumb I’ve been able to find is once the leaves start to turn yellow it’s almost time to harvest.

Can you grow a sweet potato from another sweet potato?

The simple answer is yes but not ones you’ve gotten from any grocery store. It’s common for grocery stores to treat the potatoes to prevent them from growing on the shelf but any ones grown fresh are perfect for growing more sweet potatoes.

How many sweet potatoes do you get from one plant?

Obviously, as with most things with sweet potatoes, this question depends on the type of potatoes but on average you’re going to get about one pound of potatoes per plant. This can also change depending on the climate with warmer temperatures providing a higher yield.

You know sweet potatoes are undoubtedly one of the most popular vegetables in the world and adding them to anyone's garden is an accomplishment in and of itself. We’ve seen the effort and steps it takes to actually grow a sweet potato and I’ve offered suggestions all along the way. Whether it be managing the soil temperature, creating a large enough garden space, or the whole process of curing, sweet potatoes are not easy but they are absolutely rewarding. 

Once you’ve added this vegetable to your garden I promise you’re never going to want to stop growing it when it’s in season. So go ahead and grab yourself some well-earned sweet potato pie or mashed sweet potatoes and take a break after a long gardening journey.

About the author

Greg Volente

Greg Volente holds a Naturalist Certificate from the Morton Arboretum, worked for The Nature Conservancy leading environmental education programs and doing natural areas restoration, and worked in the soil science research & testing lab at Michigan State University. Besides gardening, he's an avid wildflower enthusiast, and loves botanizing, hiking, and backpacking.