How to Grow and Harvest Sweet Potatoes

One of the most versatile plants to eat and cook, sweet potatoes are also shockingly easy to grow.

These tasty tubers can be grown directly in the garden, in a container, or even on a trellis. Some people even have success growing them as houseplants!

sweet potatoes
sweet potatoes

Sweet potatoes are a relative to morning glories, and exhibit similarities when they begin to flower. While sweet potatoes make a gorgeous addition to a flower bed, they are truly valuable for their delicious tubers.

However you choose to plant and enjoy them, you must make sweet potatoes an addition to your gardening plans next year.

Where Should I Plant My Sweet Potatoes?

Sweet potatoes can be grown around the world, but prefer warm weather and more moderate climates.

This is in direct contradiction to typical potatoes, which like colder weather. Sweet potato plants produce best when they are planted about a month after the last frost, when both the outside air and soil temperatures are nice and warm.

The reason for this is that sweet potatoes require about four months of warm temperatures in order to develop full-sized roots – the edible tubers. Vines can root wherever they are able to touch the ground, meaning just one or two plants can give you a bounty of sweet potatoes to enjoy.

These plants can grow in any soil, including poor or densely packed soil, but prefer loose, fertile ground. Heavy clay or rocky soil can cause your potatoes to form deformed roots.

Choose an area that is well-drained and is mostly loam. The ideal pH for growing sweet potatoes is between 5.8 and 6.2. Though a variety of pHs can be tolerated. more acidic soil is preferred.

If you have soil that is overly alkaline or too heavy or dense to grow sweet potatoes, consider growing your crop in raised beds or containers. There must be plenty of airspace in the soil for the roots to expand.

If your soil is of good condition and composition, but perhaps too cool (Northern gardeners – we’re looking at you), consider laying down thick black plastic or fabric mulch about three weeks before you plant.

This will help warm the soil considerably. You can then plant your sweet potatoes directly into the black plastic, or pull up the plastic and plant into the newly warmed ground.

How to Plant Sweet Potatoes

Before planting, consider adding fertilizer or other amendments to the soil.

You can fertilize after planting, but the best way to make sure your soil is ready is to add composted manure or other additives about five to six months before planting (or, ideally, the autumn before the spring in which you intend to plant).

This will give the nutrients plenty of time to work into the soil.

Try to avoid tilling your soil. This can kill beneficial microbes in the soil that will help to nurture your plants and provide for optimal growth. Instead, turn the soil lightly before planting, making sure the particles are loose and not compacted.

Sweet potatoes don’t want for much – they simply need plenty of space to sprawl. In fact, many gardeners have reported accidentally dropping pieces of sweet potatoes on the ground and being incredibly surprised later on to see that the potatoes have grown on their own – with virtually no care at all!

The key to growing a successful crop of sweet potatoes is making sure that they are provided with plenty of warm, moist soil. When you receive your sweet potato starters, you will likely be given bare root plants or slips. These are essentially just small rooted pieces of tubers.

If you don’t want to purchase these from a nursery, seed catalog, or garden store, you can also create your own by slicing a sweet potato and placing the halves on a bed of potting soil. After you cover the pieces with a bit of soil and water, the roots should develop in just a couple of days.

Slips or bare roots should be planted about twelve to eighteen inches apart. There should be three feet between rows – if not more – so that the vines have plenty of room to expand.

The most effective way to plant sweet potatoes for northern gardeners is to plant them in raised rows. These should be about seven or eight inches high to help the soil warm faster and provide for better drainage.

If you are planting sweet potatoes in a container, keep in mind that they do have a tendency to become root-bound. This is problematic, as the edible part of the sweet potato plant is the root itself.

To counteract this issue, cut each plant off just above the soil line in the container before planting it into your bed or container. This will help prevent the roots from sprawling too much as they will produce new growth instead of continuing to extend old growth.

Varieties of Sweet Potatoes

No matter which variety of sweet potato you choose, you will benefit from this vegetable’s delicious and nutritious tubers. Sweet potatoes are rich in vitamins A and C, and contain many important micronutrients as well. They can be used raw, baked, boiled, stewed, or in desserts, pastas, or stir fries. The uses are endless.

The most popular variety of sweet potatoes chosen by home gardeners are Centennial and Georgia Jet. Both of these varieties have good disease resistance, while the Georgia Jet also offers a short growing season. Beauregard sweet potatoes are commonly grown by commercial farmers, offering a high yield. Ruddy sweet potatoes have excellent pest resistance, as do Patriots, making both an excellent choice for organic gardeners.


Caring for Sweet Potato Plants

Sweet potatoes are easy to care for, but do require extensive amounts of water within the first few weeks of growth.

This plant does not require extensive fertilizer and can grow well in poor soil conditions. That being said, a little bit of fertilizer can go a long way. Consider feeding your plants with potassium-based fertilizer (or organic fertilizers like compost tea) about two weeks after planting.

Be careful not to over-fertilize or to get any mixture on the leaves. Providing plants with too much fertilizer can cause your plants to produce too much foliage and diminished root growth.

If you can, amend your soil as much as possible before planting with plenty of nutrient-dense organic matter. Mulch over the soil and fertilizer with an inch of biodegradable mulch, like shavings, grass clippings, or straw.

You will need to weed and mulch your potatoes continuously for a month or so. After this point, they will have produced enough growth where these processes are not necessary.

You will still need to provide weekly or twice-weekly deep watering, especially when conditions are particularly dry.

About a month before you plan to harvest your sweet potatoes, try to cut back on the amount of water you provide. Too much water can cause your sweet potatoes to split and will also result in premature rot.

Common Sweet Potato Pests and Diseases

Sweet potatoes aren’t prone to many diseases or pests, but can be attractants to some of the usual garden culprits. Deer, for example, especially love the leaves of sweet potatoes. You may need to erect a fence around your garden or position row covers over your plants to avoid this.

Mice are another problem experienced by sweet potato farmers. These are more difficult to detect, but planting your potatoes directly in the ground as opposed to raised beds can help. Be vigilant for signs of mouse occupation, such as disturbed soil or gnawed plants.

Other common pests include Japanese beetles, sweet potato weevils, wireworms, and nematodes. Japanese beetles feed upon the leaves of the vegetable, and while they don’t usually cause major damage, they can be an irritation to a gardener who appreciates the normally lush foliage of their plants.

Sweet potato weevils are more common in southern states, and these present a bigger problem. Sweet potato weevils attack the tubers of the plants and can wipe out an entire crop in a single feeding.

Sweet potatoes are immune to most diseases, but one fungal disease that can become a problem is scurf. Scurf is soil-borne and can live for years, lingering in the soil so long that many gardeners give up before they are able to fully eradicate it. Scurf can be avoided by planting only plants that are certified disease- free.

Crop rotation can prevent most disease and pest problems. You can also select disease- and pest- resistant varieties of sweet potatoes, regardless of whether you start them from seed, slip, or tuber.

sweet potato

Harvesting Sweet Potatoes

You will know your sweet potatoes are ready to be harvested when the vines begin to turn yellow and die back. In Northern states, this is just before the first frost. There is some finesse required in harvesting sweet potatoes, as you need to avoid injuring the tubers in any way.

To harvest, find the crown of the plant and then use a fork to lightly loosen an eighteen-inch circle around the crown. Pull up the crown with your hands, and then dig in the soil to gather up all the potatoes. It’s not a bad idea to cut back some of your vines before digging.

Be extremely careful when harvesting your sweet potatoes. If your foliage is hit by a light frost, your potatoes will probably still be fine. However, unlike other root crops, you shouldn’t let them sit in the ground, as they have more delicate skins that will rot more easily.

If you live in zones 8-11, you can actually allow your sweet potatoes to remain in the ground to produce growth for next year. However, this can be a challenging prospect for many gardeners, as the whole point of rowing sweet potatoes is to enjoy the delicious tubers!

You can also eat the greens of sweet potatoes. These are best enjoyed in a tasty salad, and should be eaten within a week of harvest.

Storing Sweet Potatoes

When you harvest your sweet potatoes, you may find that they are not terribly sweet once they first are removed from the ground. This is because sweet potatoes need time to cure before their natural sweetness is released.

To do this, simply shake off any excess soil and then lay the sweet potatoes in a warm, well-ventilated room for ten days to two weeks.

This room should be kept a about 80 to 90 degrees Fahrenheit. In some climates, this may mean heating a side room in the house, or keeping them in a warm greenhouse. In other areas, a shaded outdoor table or a screened-in porch may suffice.

As your sweet potatoes cure, you will notice that any scratches that existed in the skins of the fruits should heal, and the flesh will naturally become sweeter. Interestingly, your sweet potatoes will also develop a higher count of nutrients during this time as well.

If you don’t have time to commit to this step, you can also eat your sweet potatoes without curing.

This will work fine for casseroles or sweetened pies or desserts that don’t require additional sweetness. Uncured potatoes don’t bake or roast as well as cured ones, and they also will not hold up to long-term storage.

When you are preparing to store your sweet potatoes, you do not need to wash or rinse them. Simply brush off any excess dirt.

Washing your potatoes can lead to a buildup of moisture, which can then cause premature rot. To be safe, use a dry cloth to lightly rub your potatoes down before storage.

Cured sweet potatoes will last up to six months when stored at high humidity in temperatures of around 60 degrees Fahrenheit. A basement or pantry is a great place to store your sweet potatoes until you are ready to use them.

Do not store your sweet potatoes near certain vegetables. When placed near onions, for example, sweet potatoes can spoil and sprout more quickly. Other items that should not be placed near sweet potatoes include bananas and apples.

You can also choose to can, freeze, or dehydrate your sweet potatoes. Caned sweet potatoes should always be blanched first before preserving.

This is to ensure even heating and the elimination of all potential bacteria. They should only be preserved using a pressure canner.

Preparing Sweet Potatoes

Cooking your sweet potatoes is even easier than growing them. Simply rinse and then scrub the potato before you use it.

You can bake your sweet potatoes by rolling them quickly in olive oil, or roast them with other root vegetables, like beets or carrots. You can mash your sweet potatoes for a delectable side dish, or even bake them in casseroles or savory desserts.

If you notice that your sweet potatoes have begun to sprout before your six months of storage is up, simply cook them until they are soft and then freeze them. This will give them up to an additional year of storage time.

With all the potential uses for sweet potatoes in your everyday culinary pursuits, there is no reason not to grow them. They are easy to grow, even easier to harvest, and absolute cinch to store.

Consider including sweet potatoes in your gardening rotation next spring to add some color – and tasty nutrients! – to your diet throughout the year.

1 thought on “How to Grow and Harvest Sweet Potatoes”

  1. How do you find the crown? This is my first time growing sweet potatoes. I had no idea they would take over my garden. They are a beautiful plant and the flowers are so delicate and pretty. Thank you for writing this article.

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