Sweet potatoes may be one of the best-kept secrets for families who want to grow more of their own food without spending much money. They are nutritious, productive, relatively easy to grow, and—when properly cured and stored—can provide food for months after the garden is finished. You don’t need a large farm, either. Sweet potatoes can be grown in a garden, raised bed, or even large containers. Better yet, once you learn how to grow your own slips, a few saved sweet potatoes can help start next year’s crop.
Sometimes saving money isn’t about finding something cheaper. It’s about learning how to provide something for yourself.
Why Sweet Potatoes Are Such a Good Food to Grow
Sweet potatoes give you a lot in return for a relatively small investment. A few plants can produce a substantial harvest, and unlike many garden vegetables that need to be eaten or preserved quickly, properly cured sweet potatoes can be stored for months.
They are also remarkably versatile. Sweet potatoes can be baked, boiled, mashed, roasted, added to soups and stews, or used in breads and other dishes. They provide carbohydrates and fiber and are especially rich in beta-carotene, which the body converts to vitamin A.
For families trying to stretch the food budget, another advantage is that sweet potatoes don’t require an elaborate garden setup. They need warm weather, sunshine, adequate growing space and reasonably well-drained soil. People without a traditional garden can also grow them in large containers or grow bags.
And perhaps the best part for Mountain Know-How: you don’t necessarily have to keep buying plants every spring. With a little planning, sweet potatoes from one harvest can be used to grow slips for the next planting season.
A Sweet Potato Isn’t Really a Potato
Despite the name, a sweet potato isn’t actually a potato at all. Sweet potatoes belong to the morning glory family, while ordinary white or Irish potatoes belong to the nightshade family, along with tomatoes, peppers and eggplants.
There’s another interesting difference underground. The part of a regular potato that we eat is a tuber—an enlarged underground stem. A sweet potato is an enlarged storage root.
If you’ve ever noticed the long, trailing vines and heart-shaped leaves of a sweet potato plant, the morning glory relationship suddenly makes a lot of sense.
And here’s another misconception we might tackle in the same little section: sweet potatoes aren’t true yams either. True yams belong to an entirely different plant family.
This distinction may also be useful for people who avoid nightshade vegetables. Sweet potatoes are not members of the nightshade family, although anyone avoiding foods for medical or allergy-related reasons should follow the guidance appropriate to their individual situation.
You Don’t Have to Buy Sweet Potato Plants Every Year
Sweet potatoes aren’t usually planted from seeds or chunks of potato like Irish potatoes. They are commonly grown from slips—young shoots that develop from a mature sweet potato.
You can buy slips from garden suppliers, but you can also learn to grow your own. That means a few sweet potatoes saved from one year’s harvest can help provide the plants for the following year’s garden.
For a family working with a limited budget, that’s worth knowing. Instead of purchasing new plants every spring, you can save healthy sweet potatoes from your own crop and use them to start slips when planting season approaches.
Can You Start With a Sweet Potato From the Grocery Store?
Yes, sometimes—but there are a couple of catches. Some store-bought sweet potatoes may sprout slowly, and you may not know what variety you’re getting or how well it will perform in your area. Starting with a known variety from a garden center, local grower, or reputable supplier gives you a more predictable first crop.
After that first successful harvest, save some of your best healthy sweet potatoes for next year’s slips.
How to Grow Your Own Sweet Potato Slips
Sweet potato slips are simply shoots that grow from a mature sweet potato. Once those shoots develop roots, each one can become a new sweet potato plant.
One traditional method is to partially suspend a sweet potato in a jar of water using toothpicks, with part of the potato above the water. Place it in a warm location with good light and change the water regularly. Eventually, shoots should begin growing from the sweet potato.
Another method is to place the sweet potato partly into moist potting mix in a container and keep it warm and evenly moist. Shoots will emerge and grow into slips.
When a shoot is several inches long and has developed several leaves, it can be carefully removed from the sweet potato. The shoot can then be placed in water until it develops a good set of roots, or rooted according to the method you’re using.
Start Earlier Than You Think
Sweet potatoes love warm weather, but producing your own slips takes time. If you wait until the garden soil is warm enough to plant sweet potatoes before starting your slips, you’ll be late.
For that reason, plan on beginning the process several weeks before your expected planting time. We’ll give readers a specific timetable later in the article so they can work backward from their area’s planting season.
Mountain Know-How Tip
When to Plant Sweet Potatoes
Sweet potatoes are a warm-weather crop. Don’t rush them into cold spring soil. Wait until the danger of frost has passed, the soil has warmed, and nighttime temperatures are reliably mild.
Unlike Irish potatoes, which can tolerate cool spring weather, sweet potatoes grow best once genuinely warm weather has arrived. Planting too early can slow their growth and may result in a poorer crop.
Choose a location that receives full sun and has loose, well-drained soil. Heavy or compacted soil can make it harder for the storage roots to develop properly.
Give Them Room to Spread
Sweet potato vines can travel surprisingly far. Plant slips roughly 12 to 18 inches apart, with enough room between rows for the vines to spread.
If garden space is limited, don’t let that stop you. Sweet potatoes can also be grown in raised beds, large containers or grow bags, provided there is adequate soil volume, drainage, sunlight and warmth.
How to Plant Sweet Potato Slips
Once the weather and soil are warm, sweet potato slips are simple to plant. Each slip should have a healthy stem and several leaves. If you’ve rooted your slips in water first, they may also have a cluster of roots.
Make a hole deep enough to bury the roots and several inches of the lower stem, leaving the leafy portion above the soil. Gently firm the soil around the slip and water it well.
Don’t worry if newly planted slips look a little wilted at first. Transplanting can be a shock, particularly on a hot day. Keep the soil adequately moist while the plants become established. Once they begin putting out new growth, you’ll know they’re settling in.
Don’t Overdo the Fertilizer
Sweet potatoes don’t need to be pampered. In fact, excessive nitrogen can encourage lots of beautiful vines while producing fewer sweet potatoes underground.
If your soil is reasonably fertile, don’t assume you need to spend money on bags of specialty fertilizer simply because the garden center has them. Compost and ordinary soil improvement may be enough, depending on your soil.
If you’re unsure about your soil, a soil test through your local Cooperative Extension office can tell you what it actually needs—and can keep you from spending money on products it doesn’t need.
Caring for Sweet Potatoes During the Summer
Once sweet potatoes become established, they are fairly easy plants to care for. Their vines will begin spreading across the ground, helping shade the soil and suppress some weeds.
Water is most important while the slips are becoming established and during extended periods of hot, dry weather. Sweet potatoes can tolerate some dryness once established, but prolonged drought can reduce the harvest. At the same time, constantly soggy soil isn’t good for them either.
Weed around young plants until the vines begin covering the ground. After that, the vines themselves can make weed control much easier.
Don’t Let the Vines Fool You
A sweet potato plant can produce an impressive amount of vine growth, but the goal isn’t to grow the prettiest vines in the neighborhood. What matters is what’s developing underneath the soil.
Avoid continually adding high-nitrogen fertilizer just because the vines look as though they could use a boost. Too much nitrogen can favor leafy growth rather than the storage roots you’re hoping to harvest.
Don’t Forget the Leaves: They’re Food Too
One of the lesser-known benefits of growing sweet potatoes is that the leaves and tender young shoots are edible. While most Americans grow sweet potatoes for the roots, sweet potato greens are eaten as a vegetable in many parts of the world.
The young leaves and tender stems can be cooked much like other greens. They can be sautéed, steamed, boiled, or added to soups and other dishes. Their mild flavor makes them an easy way to add another fresh vegetable to a meal from a plant you’re already growing.
That means a sweet potato patch can potentially provide food during the growing season as well as at harvest time.
Don’t strip a plant bare, however. The leaves are doing the work of producing the energy the plant needs to develop those sweet potatoes underground. Harvest modest amounts of young leaves from healthy, vigorous vines and leave plenty of foliage on the plant.
Be Sure You’re Growing Sweet Potatoes
Don’t assume the leaves of ordinary white or Irish potatoes can be used the same way. They cannot. Irish potatoes are members of the nightshade family, and their foliage contains toxic glycoalkaloids and should not be eaten.
When and How to Harvest Sweet Potatoes
Sweet potatoes need a long, warm growing season, so give them as much time as your weather safely allows. Depending on the variety and growing conditions, many are ready roughly 90 to 120 days after planting.
You can carefully check one plant as harvest time approaches to see how the roots have developed. Don’t expect every sweet potato to be the same size. You may find everything from small ones perfect for a single serving to some surprisingly large ones.
Try to harvest before a hard frost. Cold temperatures can damage sweet potatoes and shorten their storage life.