I used to be vegetarian for a long time, then added meat back into my diet because of a nutrient deficiency. We try to not eat too much meat in my household, so sweet potatoes often make an appearance on the menu instead. They’re nutritious, filling, and incredibly versatile.
In fact, I eat them so often it seems worth it to sacrifice a spot in my garden for this heat-loving root veggie. The key to growing them in an area without a long hot growing season is picking the right variety and to plan ahead if you have variable weather. If you’ve been gardening for any amount of time, you know that where there’s a will, there’s a way! With a little bit of adjustment, ingenuity, and care you can manage to grow anything nearly anywhere – including this delicious tuber.
Much sweeter than a regular starchy potato, this colored version of the humble tater is actually from a completely different family and has different care requirements. Read on to find out how to succeed at growing sweet potatoes.
Are Sweet Potatoes and Yams the Same Thing?
The age old question! They look somewhat similar but they aren’t from the same family. So why do they get confused? Because most folks use the term yam to refer to sweet potatoes, which is incorrect. Yams typically take on the same oblong shape as sweet potatoes do, but their skin is a whole lot thicker, and the flesh is never orange. The flavor and texture of yams are very different than that of sweet potatoes. They’re not very sweet, and the flesh is meaty and has less moisture.
Sweet Potato Varieties
The best part of growing your own produce is that you can choose among a variety of hard-to-find cultivars. I love growing vegetables that I can never find at my local supermarket. If your grocery store is anything like mine, you probably only have the option to buy orange-fleshed sweet potatoes. They’re what I think of when I think of this veggie, but there a myriad of other options with different colored flesh and skin.
- Jewel – Jewel has a bright orange meaty flesh and it's one of the most popular varieties. Semi-bush growth habit.
- Okinawa – A Japanese sweet potato variety with purple flesh. Vining plant.
- Garnet – Similar flesh to the Jewel variety, but the skin has a deeper reddish hue. Vining plant.
- Centennial – A excellent variety for those in northern climates with short growing seasons.
- Creamsicle – This type looks almost like an oddly shaped parsnip thanks to its cream-colored skin, but has a surprisingly bright orange interior.
- Covington – One of the sweeter varieties, it’s a perfect choice for gardeners who love to bake.
- Willowleaf – An heirloom sweet potato variety with a distinct nutty flavor. Semi-bush habit.
- Purple – Mildly sweet with a thick flesh that’s best used for savory recipes and not desserts. Vining.
Planting Sweet Potatoes
Sun and Temperature Requirements
The first thing you should know about growing sweet potatoes is that they love hot weather! A long hot growing season is ideal for growing these tuber-like roots. If your summer is short, pick an early variety like Beauregard or Georgia Jet to ensure you'll have enough time to harvest and cure your potatoes before frost arrives. The sweet potato is suitable for growing in zones 3-11 as an annual, and zones 8-11 as a perennial.
Whether you decide to plant in beds or in grow bags, choose a spot that provides full-sunlight for most of the day.
Soil Requirements
Sweet potatoes need a loamy soil with a pH between 5.0-6.5. You should amend your soil with lots of rich organic matter and make sure that it is well drained.
Sweet potatoes aren't finicky about the texture of the ground they grow in, but if your soil is full of rocks and clumps, you may end up with oddly shaped potatoes at the end of the season.
Slips or Store Bought Potatoes
Typically, sweet potatoes are grown from purchased slips, but it’s possible to root a store-bought sweet potato, as well.
When to Begin Rooting
Begin the rooting process about 6-8 weeks before your last frost date. Rooting your own sweet potatoes will take up to a month, so be patient! If you purchase slips from a seed company, they'll usually ship them out around the time it's suitable to plant them outdoors.
How to Sprout Sweet Potatoes
Put your sweet potatoes into some loose potting soil in a warm, humid area until sprouts start to form. Then, transfer to an area with some filtered sunlight until the sprouts are ready to plant. Some people will tell you to root in water without the soil, but plants tend not to form as strong of root systems this way.
Planting Outdoors
Once you've got your hands on some sweet potato slips and the chance of frost has passed, plant them in foot-wide hills of amended earth. I'd recommend dedicating a single bed to growing sweet potatoes since the vines will require some room to spread.
When planting, cover the slips in dirt but leave the leaves exposed. Water your slips once they've been transplanted. Remember, it's super important that you plant them a few weeks after the chance of frost has passed, and warm temperatures have arrived for the season. Sweet potatoes are quite sensitive to frost.
Potato Grow Bags
If you're lacking space or good soil, you can try growing sweet potatoes in potato grow bags. This is also an excellent option if you are worried the temperatures might dip because you can bring them indoors temporarily.
Spacing
Give plants 12-18 inches between each other, and 3-4 feet between plant rows. Plant them so that there's about 1/2 of stem above the ground and the roots are covered.
Mulching
To ensure that your baby plants stay toasty, use some kind of mulch to help warm the soil. Many gardeners like to use black plastic mulch when growing sweet potatoes for this reason.
Caring for Sweet Potatoes
Here are a few tips for keeping your sweet potatoes happy throughout the growing season.
Watering
Water weekly but avoid overwatering, which will quickly cause rot. Sweet potatoes can tolerate periods of drought but are less likely to survive waterlogged soil.
Protect from Frost
If a random drop in temperature is expected, cover with a frost blanket to protect your plants. If your sweet potatoes are in pots, bring them in if the forecast calls for an unexpected drop in temperature overnight.
Fertilizing
Avoid nitrogen fertilizer, which will increase foliage growth and diminish root output. Fertilize with low-nitrogen fertilizer or plenty of compost when planting.
Pruning
There’s no need to prune growing sweet potatoes unless you are struggling with mold. If needed, thin out about 20% of the leaves to improve air circulation.
Weeding
Weed regularly to eradicate invasive plants that may compete with your sweet potatoes for nutrients and sunlight, and that can bring diseases.
Sweet Potato Problems and Solutions
There are a few problems to look out for when growing sweet potatoes.
Problems
- Sweet potatoes don’t taste great: You’ve left them in the ground too long, and they’ve been exposed to frost, or you didn’t take the time to cure your tubers. Not curing your roots makes them more likely to rot in storage.
- Slips withering and dying: Uh oh! That’s a huge disappointment. If your transplanted slips are not thriving, it may be that they’re lacking moisture. Otherwise, you may have purchased diseased or poor quality slips.
- Small, scraggly sweet potatoes: This is likely due to overwatering. Your best bet for big sweet potatoes is to water evenly throughout the season.
- Mishappen sweet potatoes: Rocky or clumpy soil is the likely culprit. Make sure your soil is loamy and well broken-up.
Alternaria Leaf Spot and Leaf & Stem Blight
Blight and Alternaria leaf spot causes brown rings with a light center and a yellow halo. It's caused by a fungus, and there is no cure. Plant resistant varieties and destroy any infected plants.
Black Rot
Black rot is a fungus that can affect sweet potatoes. It’s essential to get rid of infected potatoes to prevent the spread of the disease. Don’t use slips from infected plants for planting.
Fusarium and Verticillium Wilt
These fungi cause distorted stems and a dark rot that extends into the roots. You'll first see yellowing leaves at the base of the plant, followed by white mold as the plant dies. Be sure to use disease-free slips, rotate your crops and sanitize tools to prevent spreading it. You can also solarize your soil between plantings.
Bacterial Soft Rot
If your plants are infected with this bacteria, you'll see moist lesions that cause parts of the plant to wilt and collapse. Plant resistant varieties and remove and destroy any infected plants.
Common Scab
Scab causes brown, woody scabs on growing sweet potatoes and will cause leaves to curl. It's caused by a fungus and is spread by water. Avoid overhead watering and be sure to rotate crops. If the infection is severe, use an organic fungicide.
Potato Leafroll
This virus can cause stunted plants and reduced yield. You'll notice leaves that are rolled at the margins and plants that aren't thriving. It's spread by aphids, so keep them under control and destroy any infected plants you find.
Potato Stem Borer
These pests emerge from grasses in early summer in warm, wet areas, looking for dinner. You'll know you have them if you see a hole at the base of the stem of your sweet potatoes. The best way to control them is to spray your grass with insecticide in late spring and early summer.
Aphids
Like most plants, sweet potatoes are susceptible to aphids. These tiny insects gather on lower leaf surfaces and buds and suck the energy from a plant. Treat with neem oil.
Cutworms
The cutworm lurks close to the soil and cuts plants off at the stem near the ground. You can use cardboard plant collars and diatomaceous earth to control them. If things get bad, you can also use an organic insecticide.
Whiteflies
These tiny flies hang out on the underside of leaves and secrete sticky honeydew that can attract mold. Use insecticides like Admire to control them, along with traps and neem oil.
Root Knot Nematodes
Root knot nematodes cause stunted growth and plant dieback, as well as galls on the roots. Rotate crops and grow cover crops like marigolds, which is toxic to nematodes. Soil solarization is also effective.
Flea Beetles
Flea beetles are another annoying pest that targets sweet potato foliage. Get rid of the little black beetles using a homemade bug spray using a mix of soap and cayenne. You may also have success with row covers to prevent an infestation.
Scurf
Sweet potato scurf is another fungus that affects the skin of the vegetable. Affected tubers will have patches of grey or brown. Avoid overwatering since this disease is encouraged by high levels of moisture.
Companions for Sweet Potatoes
Best Companions
Sweet potatoes are vining plants that take up a bit of room, not unlike vining squash plants, so you may not want to plant anything nearby that may get crowded out. Still, there are a few great companion plants for this sweet root vegetable.
- Beets
- Parsnip
- Salsify
- Beans
- Potatoes
- Dill
- Thyme
Worst Companions:
Squash is a fierce competitor for sweet potatoes. Both are spreaders and require plenty of room to grow, so making them neighbors is a bad idea. Tomatoes share some of the same diseases, so it's best to keep them apart.
Harvesting and Storing Sweet Potatoes
Sweet potatoes are typically ready for harvest 3-4 months after you put the slips on the ground once the plant has begun to wither and die back. Don’t wait until after your last frost date to harvest! Waiting too long and exposing sweet potatoes to frost will likely leave you with rotted roots at the end of a long season.
Carefully dig out tubers with your hands or gently move dirt with a spade taking care not to knick or dent your potatoes.
Curing Sweet Potatoes
Curing sweet potatoes before storing helps to transform the fleshy part from starchy to sweet and helps them keep longer in storage. The process involves keeping the potatoes exposed to high humidity and hot temperatures for about a week.
This is the toughest part for northern growers who will likely be harvesting their sweet roots sometime in the fall when temperatures and humidity are lowering across the board. Once cured, store sweet potatoes in a cool, dry area.
To save sweet potato slips for planting again in the following year, spare a few potatoes from the dinner table. Smaller roots work better than large ones.
Note: uncured sweet potatoes spoil very quickly. Use them within 7 days.
Recipes for Using Your Garden Sweet Potatoes
Here are a few of my favorite ways to use the tasty sweet potato in the kitchen.
Mashed – sweeter than regular mashed potato, mashed sweet potato pairs deliciously with many proteins including steak and pork loin.
Stuffed – The meat of a sweet potato is super filling and full of nutrients so stuffing this root makes for a complete meal. Stuff with ground beef and peppers and top with salsa for a Mexican twist or with quinoa and roasted veggies for a satisfying vegetarian entree.
Tempura – Tempura fried sweet potato coins make a great side dish for a sushi party!
Roasted – One of my favorite ways to use sweet potato is to cube it, toss in olive oil and garlic salt, then roast in the oven. Once the cubes are tender, I throw the warm sweet potato in with a few other ingredients to make a delicious salad. It makes a great potluck side dish but works as a meal, too.
Canned – If you can't use up all those delicious tubers fast enough, try canning them.
Check out our 35 favorite sweet potato recipes for more ideas.
Have you had any luck growing sweet potatoes? Let us know in the comments! I've got my slips ordered for this year and can't wait to experiment with a whole new plant.
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