Information About How To Harvest Sweet Potatoes

So you’ve decided to grow some sweet potatoes in the garden and now you need information about when and how to harvest sweet potatoes once they’ve matured. Read on to learn more.

When to Harvest Sweet Potatoes

When to harvest sweet potatoes depends largely on the seasonal growing. If the growing season has been good with adequate water and sunshine, harvesting sweet potatoes should begin about 100-110 days after planting depending on the variety. A good rule of thumb is to watch for the first signs of yellowing leaves. Usually this occurs in late September or early October before the first frost.

Many people think frost won’t affect your harvest. Sweet potatoes are well insulated underground, after all. The truth is once those vines blacken with frost bite, the answer to when to dig sweet potatoes becomes — Right Now! If you can’t harvest sweet potatoes right away, cut those dead vines off at the ground so the decay doesn’t pass to the tubers below. This will buy you a few more days for harvesting sweet potatoes. Remember, these tender roots freeze at 30 F. (-1 C.) and can be injured at 45 F. (7 C.).

When deciding when to harvest sweet potatoes,

choose a cloudy day if possible. The thin skins of the newly dug potatoes are susceptible to sunscald. This can open the way for infection to enter the tubers and cause damage during storage. If you must harvest sweet potatoes on a sunny day, move the roots to a shaded spot as quickly as possible or cover them with a tarp.

How to Harvest Sweet Potatoes

How to harvest sweet potatoes is every bit as important as when to harvest. Sweet potatoes have delicate skin that is easily bruised or broken. Be sure you sink your garden fork far enough out from the plants to avoid striking the tender roots. Don’t toss the freed potatoes into your carrying container. Place them carefully.

A potato that has been damaged by cuts and bruises will leak a milky juice over the injury. Some people believe this juice seals the injury. It doesn’t. Minor scrapes will heal during the drying process, but the best practice when harvesting sweet potatoes is to set deeply cut roots aside to be eaten first.

Washing the newly dug roots is another common mistake made by many home gardeners when harvesting sweet potatoes. Newly dug roots should be handled as little as possible and moisture should never be added.

What to Do After Harvesting Sweet Potatoes

When we talk about how to harvest sweet potatoes, it’s important to note that it’s more than just knowing when to dig. Sweet potatoes must be cured after harvest and before they are stored.

After digging, allow the roots to dry for two to three hours. Don’t leave them out overnight where cooler temperatures and moisture can damage them. Once the surface is dry, move them to a warm, dry, well ventilated place for 10-14 days. This will not only allow the skins to toughen, but will increase the sugar content. You’ll notice the color change to a deeper orange after several days.

When your potatoes are thoroughly cured, pack them carefully in boxes or baskets and store in a cool, dry, darkened place for the winter. Properly cured sweet potatoes can be stored for six to 10 months.

Knowing how to harvest sweet potatoes properly can increase your storable yield as well as the pleasure derived from enjoying your harvest all winter long.

Harvesting Sweet Potatoes

If you’re like me, the start of fall is not only exciting for the refreshing cooler weather it brings: It also means I can put up my canning equipment. The wonderful, hearty fall vegetables — winter squashes, potatoes and, of course, sweet potatoes — can store themselves for several months if harvested and stored properly. Sweet potatoes, with the high vitamin content found in their orange flesh, are an especially great and versatile fall and winter food.

After watching the beautiful, winding vines cover your garden beds through the summer months, it can be hard to know when it’s the right time to go grab the spading fork and dig out the fleshy tubers. While sweet potatoes can be dug as soon as the tubers have reached a suitable size — between three and four months after planting the slips — the flavor and quality improves with colder weather. Some even wait until after the first frost has blackened the leaves, but only if you can get all your sweet potatoes out of the ground quickly and right away. Rodale’s Encyclopedia of Organic Gardening makes the following recommendation: “You can harvest as soon as leaves start to yellow, but the longer a crop is left in the ground, the higher the yield and vitamin content. Once frost blackens the vines, however, tubers can quickly rot.”

The most common tool for digging sweet potatoes out of the ground is a spade fork, although a shovel will work, and the ambitious harvester can even adapt a broad fork to dig more plants at one time. If you have a large plot, you can adjust a mold-board plow to mechanically turn the sweet potatoes out of the ground. Tubers can grow a foot or more away from the plant, so give ample space to prevent nicking and damaging the skin, as this encourages spoilage. Digging is much easier when the soil is dry, and mud-coated sweet potatoes are less likely to sun-dry properly and rapidly.

Dry freshly dug sweet potatoes in the sun for several hours, then move them to a curing room. Although you can cook sweet potatoes fresh out of the ground, the natural sweetness improves after curing. Proper curing also heals injuries incurred to the tubers during harvest, which helps guarantee successful storage. The simplest curing method is to place the sweet potatoes in newspaper-lined boxes in a warm, well-ventilated room — ideally between 85 and 90 degrees Fahrenheit at around 85 percent humidity — for a week to 10 days. A hoop house or green house works well for this, but any space where you can control the temperature will work. After curing, move the sweet potatoes to a storage space, such as a root cellar, kept between 55 and 60 degrees with humidity of 75 to 80 percent. (If you don’t have a root cellar, you can build your own basement root cellar.)

Now that you have your sweet potatoes dug, cured and stored, look for some great sweet potato recipe ideas on our Relish! blog.


Photo from Flickr/David Bradbeer

Growing Sweet Potatoes(Impomoea Batatas)

How To Grow Sweet Potato Vines At Home

Growing Sweet Potatoes is very easy in tropical and sub tropical climates.
(And not difficult in cool climates, either.)

In fact, the question is not how to grow sweet potatoes, it’s rather how to stop sweet potato vines from taking over the whole garden! Sweet potato is a very invasive creeper…

But even though they can be a pain in the you know what if not managed (harvested regularly), you absolutely have to grow sweet potatoes! Why?

Sweet potato is one of the most useful food plants in a warm climate:

  • Sweet potatoes are the perfect substitute for normal potatoes.
  • Sweet potatoes have less disease problems.
  • Growing sweet potato vines is much easier than growing other potatoes.
  • Sweet potatoes are very nutritious.
  • And sweet potatoes grow with little water and fertilizer.

You can use sweet potatoes in the kitchen just like you would use potatoes. Boil them, steam them, mash them, fry them… But sweet potatoes have more uses:

  • You can eat young sweet potato shoots and leaves in stir fries and salads.
  • Sweet potatoes also make a wonderful quick growing ground cover.
  • You can use them as a living mulch and to keep weeds down.

So, how do you grow sweet potatoes, and how do you keep them under control?

How To Grow Sweet Potatoes

Sweet potato plants are fast growing vines that cover the ground.

Originally they come from Central and South America, which means they are a warm weather vegetable. You need a long warm season to grow good sweet potatoes.

There are sweet potato varieties with red, yellow and white tubers. The red ones have the highest carotenoid content and have become the most popular variety. But all sweet potatoes are very nutritious in general, especially if you use the leaves and shoots, too.

You’ll be hard pressed to find a plant that produces more nutrition per square metre than the humble sweet potato!

What Sweet Potatoes Like And Dislike

Sweet potatoes like growing in sandy soils, lots of sun, lots of space, and a reasonable amount of water and nutrients. They love heat. The hotter it is the faster they grow.

Sweet potatoes don’t like heavy, waterlogged soils, cold weather, and fertilizers high in nitrogen (like chicken manure, it makes them grow lots of leaves but no potatoes).

Propagating Sweet Potatoes

The quickest and easiest way to grow sweet potatoes is to use cuttings. Simply cut a piece of a runner, about a foot (30 cm) in length.

Remove all the leaves except for the tiny leaves at the very tip. Plant the cutting by covering the whole length with soil, only the leaves of the tip should stick out of the ground.

The cuttings will root at every leave node. Not just the leave nodes under the ground will root. A sweet potato also grows roots from every leave node that develops as your cutting grows.

If you can’t get hold of cuttings you can start growing sweet potatoes by planting the tubers. You can use any shop bought sweet potatoes.

Place them on the ground, cover them with soil, and keep them moist. The tubers will develop shoots, called slips.

Slips can be snipped or pulled off and planted out when they are about 15 cm in size. The original root will continue to produce more slips.

Growing Sweet Potatoes In Water

It’s a popular project in school classes: growing sweet potato vines in a glass of water. You can do that by putting a tuber into water, pointy end down, with the top third above the water. Slips will grow from the eyes of the tuber.

You can plant those shoots out just like the slips grown in soil.

Some people root the slips in water as well. It’s nice to watch for children but it has no benefit whatsoever. Rooting any plant in a glass of water does not make sense other than for demonstration and teaching purposes.

The best soil for sweet potatoes is sandy but they can grow in all soils. If you have heavy soil plant sweet potatoes on mounds or ridges.

Raising the beds improves the drainage (very important) and gives the tubers a nice deep soil to develop in. (Otherwise you may end up with small, bent and forked sweet potatoes.)

The soil should have a good supply of nutrients, for example from digging in mature compost. Do not use fresh manures or any fertilizers high in nitrogen (like pelleted chicken manure). You’d just end up with lots of leaves and no tubers.

Growing sweet potatoes requires some space, so plant them where they can spread. Space your cuttings or slips about a foot apart in a row, and leave three to four feet between rows. (If you plant in rows, that is.)

Mulch thickly between plants and even between the beds to initially keep the weeds down. Once the sweet potatoes grow they will choke all weeds down themselves.

For planting time the general recommendation is to plant a patch in spring. (May in the northern hemisphere, November in the southern). In a cool climate you may indeed have to get by with a single planting. Sweet potatoes do need four to six months of reasonably warm weather to mature.

But in the tropics one big spring planting does not make sense, unless you are a commercial grower.

Sweet potatoes don’t keep well after harvest, so the best way is to plant a few cuttings every week or two. Just one row of one metre length, with three cuttings. They will take about 16 to 18 weeks to mature in warm weather, longer in cooler weather.

That way you can grow sweet potatoes all year round, and you don’t find yourself with a big pile of them all at once.

Growing Sweet Potatoes The Lazy Way

If you have enough room you can also plant a permanent sweet potato patch. I did.

When I started growing sweet potatoes I didn’t plant in rows. I have plenty of space, so I planted some sweet potatoes as a ground cover under most of my fruit trees.

They did extremely well, and now my whole orchard is covered in sweet potatoes. They don’t need any care, and when I want some sweet potatoes I can usually find a few there. I just look for a thickened stem, or walk around feeling for a lump, and start digging. It’s too easy.

How Much Water? How Much Plant Food?

Although sweet potatoes are a very tropical vegetable they can get by with little water once established. However, the freshly planted cuttings need to be watered regularly.

Make sure plants don’t become waterlooged. If your soil isn’t free draining it’s safest to grow sweet potatoes on mounds.

If you think the quality of your soil is not good enough fertilize your plants at planting time, at six weeks of age, and maybe once more at twelve weeks. Or whenever you remember to do it…

Just make sure you use a balanced fertilizer, for example seaweed extract. A sprinkle of sulfate of potash also doesn’t go astray. Compost that had lots of wood ash in it is even better. Avoid high nitrogen fertilizers. Root crops like potassium and phosphorus, not nitrogen.

Harvesting Sweet Potatoes

After four to six months, depending on the temperatures, your sweet potatoes will be ready. You will see that the original stem of your cutting or slip will have thickened, and when you carefully lift the plant with a fork you should find two or three sweet potatoes at the base.

You can harvest sweet potato leaves and young shoots at any time, it does not affect the plant or tubers.

Problems When Growing Sweet Potatoes

In the tropics sweet potatoes have one serious pest, and that’s the sweet potato weevil. An adult weevil is a metallic blue and orange and about 6 mm long. It eats everything, stems, leaves and roots. The weevils lay their eggs in the roots and the larvae tunnel through the roots and make a rotten mess of them.

If you have problems with sweet potato weevils you can’t grow a permanent sweet potato patch. Just use the other sweet potato growing method.

Plant slips or cuttings, that way you don’t transfer any weevils. Dig up the whole crop, don’t leave any tubers in the ground, and start afresh with cuttings in a different bed. That way weevils will never be a problem again.

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What are the next steps after digging sweet potatoes? How do I cure the spuds I have just dug? Due to a wetter-than-usual summer, the tubers are unusually large. I would like to ensure that I don’t lose them to decay.

I’ve just finished harvesting sweet potatoes in my own garden. Like you, this year’s harvest has yielded some of the biggest sweet potatoes ever.

Sweet potato varieties are ready to harvest 95 to 120 days after planting in the garden. When the leaves turn slightly yellow they are usually ready to harvest. Because they have thin skins sweet potatoes are easily damaged during harvest so extra care should be taken. Some people even go so far as to wear cotton gloves when harvesting as to not harm the potatoes. Cutting the vines 2 or 3 days before you plan to dig will toughen up the skins.

After harvest, the sweet potatoes should be cured. This involves placing the potatoes in a warm (85 degrees) humid (90 percent) environment for about 4 to 6 days to increase sugar content, heal nicks and bruises incurred during harvest, and increase flesh color.

Once cured, store your sweet potatoes in dry boxes or bins in a room that’s humid and 55 to 60 degrees F. The ideal place to store sweet potatoes is in a root cellar or cool pantry. Do not store them in the refrigerator because low temperatures will cause the sugars to turn to starch.
They can be stored for 6 to 10 months under good conditions.

In the garden, on a trellis, or in a container, sweet potatoes are a beautiful plant. The delicious tubers in the fall just come as an added bonus to the lovely foliage and flowers.

Sweet potatoes grow well in a sunny vegetable garden, but you can also grow them in other parts of your home landscape. Try them as a temporary groundcover or a trailing houseplant. In a patio planter, a sweet potato vine will form a beautiful foliage plant that you can harvest roots from in the fall.

Related Story

This warm-weather crop grows worldwide, from tropical regions to temperate climates. The flesh is classified as either moist or dry. Moist, deep orange types (sometimes called yams) are more popular with home gardeners, especially the varieties Centennial and Georgia Jet.

Sweet potatoes are also remarkably nutritious and versatile; each fleshy root is rich in vitamins A and C, along with many important minerals. Use them raw, boiled, or baked, in soups, casseroles, desserts, breads, or stir-fries — and don’t forget to try some homemade sweet potato fries!



Sweet potatoes will grow in poor soil, but deformed roots may develop in heavy clay or long and stringy in sandy dirt. To create the perfect environment, create long, wide, 10-inch-high ridges spaced 3½ feet apart. (A 10-foot row will produce 8 to 10 pounds of potatoes.)

Work in plenty of compost, avoiding nitrogen-rich fertilizers that produce lush vines and stunted tubes. In the North, cover the raised rows with black plastic to keep the soil warm and promote strong growth.

It’s best to plant root sprouts, called slips, available from nurseries and mail-order suppliers. (Store-bought sweet potatoes are often waxed to prevent sprouting). Save a few roots from your crop for planting next year.

About six weeks before it’s time to plant sweet potatoes outdoors in your area, place the roots in a box of moist sand, sawdust, or chopped leaves in a warm spot (75 to 80 degrees). Shoots will sprout, and when they reach 6 to 9 inches long, cut them off the root. Remove and dispose of the bottom inch from each slip, as that portion sometimes harbors disease organisms.

Sweet potatoes mature in 90 to 170 days and they’re extremely frost sensitive. Plant in full sun three to four weeks after the last frost when the soil has warmed. Make holes 6 inches deep and 12 inches apart. Bury slips up to the top leaves, press the soil down gently but firmly, and water well.


Logan Mock-Bunting/getty

If you’re not using black plastic, mulch the vines two weeks after planting to smother weeds, conserve moisture, and keep the soil loose for root development. Occasionally lift longer vines to keep them from rooting at the joints, or they will put their energy into forming many undersized tubers at each rooted area rather than ripening the main crop at the base of the plant. Otherwise, handle plants as little as possible to prevent wounds that vulnerable disease spores.

If the weather is dry, provide 1 inch of water a week until two weeks before harvesting, then let the soil dry out a bit. Don’t overwater, or the plants — which can withstand dry spells better than rainy ones — may rot.

Protecting Against Pests


Southern gardeners are more likely to encounter pest problems than gardeners in Northern areas.

Sweet potato weevils — ¼-inch-long insects with dark blue heads and wings and red-orange bodies — puncture stems and tubers to lay their eggs. Developing larvae tunnel and feed on the fleshy roots, while adults generally attack vines and leaves. They also spread foot rot, which creates enlarging brown to black areas on stems near the soil and at stem ends. Since weevils multiply quickly and prove hard to eliminate, use certified disease-resistant slips and practice a four-year crop rotation. Destroy infected plants and their roots, or place in sealed containers and dispose of them with household trash.

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Fungal diseases include black rot, which results in circular, dark depressions on tubers. Discard infected potatoes, and cure the undamaged roots from the same crop carefully. Don’t confuse this disease with less-serious scurf, which creates small, round, dark spots on tuber surfaces but doesn’t affect eating quality.

Stem rot, or wilt, is a fungus that enters plants injured by insects, careless cultivation, or wind. Even if this disease doesn’t kill the plants, the harvest will be poor. Minimize the chances of disease by planting only healthy slips; avoid black and stem rot by planting resistant cultivars. Reduce the incidence of dry rot, which mummifies stored potatoes, by keeping the fleshy roots at 55 to 60 degrees.



You can harvest as soon as leaves start to yellow, but the longer a crop is left in the ground, the higher the yield and vitamin content. Once frost blackens the vines, however, tubers can quickly rot.

Use a spading fork to dig tubers on a sunny day when the soil is dry. Remember that tubers can grow a foot or more from the plant, and that any nicks on their tender skins will encourage spoilage. Dry tubers in the sun for several hours, then move them to a well-ventilated spot and keep at 85 to 90 degrees for 10 to 15 days. After they are cured, store at around 55 degrees, with a humidity of 75 to 80%. Properly cured and stored sweet potatoes will keep for several months.

Sweet Potatoes EN


Just like regular potatoes, their origins lie in Southern America. The Inca were already cultivating sweet potatoes 800 year after Christ. It was probably Columbus who brought the first sweet potatoes to Europe.

Sweet potatoes are not potatoes

Unlike regular potatoes, which are tubers, sweet potatoes are considered to be root vegetables. The root, however, is described as a tuberous root. Both sweet and regular potatoes grow under the soil, but they are very different when it comes to density, taste and nutrition.

Sweet potatoes are in the plant family Convolvulaceae (morning glory) Ipomoea batatas potato, Solanaceae (nightshade) S. tuberosum.

At first glance, the exterior of the sweet potato seems to be the same as a normal potato; on closer inspection however, the skin colour and the shape are very different.

In terms of flavour, sweet potatoes taste more like carrots. The flavour is very sweet, as the name suggests. The ‘brix’ level (the level of sweetness) will vary between the different varieties. This depends on the place where they were grown and the variety which was used. It is clear, however, that we cannot really compare sweet potatoes with regular potatoes.

Another difference between the normal and the sweet potato is the nutritional value.

More about the nutritional value of the sweet potato can be read here.

How do they grow

Nowadays, sweet potatoes are cultivated in America, Asia and New Zealand. China is the world’s largest producer of sweet potatoes; the USA, however, is the most professional grower. Most sweet potatoes are grown in the State of North Carolina, however other states such as California, Louisiana and Mississippi also grow the crop.

It is very hard to grow sweet potatoes in Europe. The sweet potato is a tropical vegetable which means it needs a long warm season of 110 days with temperatures of at least 30 degrees Celsius. The nights must also be fairly warm (above 20 degrees Celsius). And of course, just like every other crop, it needs enough water.

In May the small seedlings are planted out close to each other in the fields. Later in the summer, when the seedlings have grown into small plants, they are replanted in the fields and in September/October the sweet potatoes are harvested. Most of these harvesting activities have to be done by hand.

On average, an American grower harvests 15 to 20 tons per hectare, much less than a regular potato grower in Europe.

After the harvest the farmer stores the fresh crop in wooden crates in cold, well ventilated dry and dark storage barns, where the sweet potato will stay in good condition for 12 months. Sweet potatoes are available the whole year round.

How to store sweet potatoes at home.

The best advice is to buy fresh potatoes at the supermarket or greengrocer. They can be stored outside the refrigerator in a dark, cool, well ventilated place, like normal potatoes. You will then be able to keep the sweet potatoes for up to two weeks.

A sweet potato isn’t a potato, and other myths

The sweet potato is versatile and can be eaten as a healthy snack or added to dishes, like soups and casseroles, in bread recipes and even smoothies. But it’s also misunderstood.

Myth: A sweet potato is an orange potato.

Fact: Even though both the potato and sweet potato originated from Central and South America, they are actually not related. They come from different families, with the potato coming from the nightshade and the sweet potato from the morning glory family.

Myth: Sweet potatoes are yams.

Fact: Yams and sweet potatoes are not the same vegetable and they have different tastes. Back in the 1930s, “yams” was used as a marketing term for sweet potatoes and still to this day, you might find the two mislabeled in stores. They’re grown from different families, with yams coming from the same family as grasses and palms. Sweet potatoes are typically grown in the U.S. while yams are imported.

Myth: The sweet potato is all starch and doesn’t contain many nutrients.

Fact: The sweet potato is an excellent source of vitamins A and C and a good source of vitamin B6, potassium and manganese. One medium sweet potato contains only 100 calories. Also, the fiber content is 15 percent of the daily value along with 16 percent for vitamin B6, 15 percent potassium, 28 percent manganese and 10 percent pantothenic acid. These vegetables are an excellent source of vitamin A (438 percent of the daily value) and vitamin C (37 percent of the daily value) and contain no saturated or trans-fat or cholesterol.

Myth: The outer skin of sweet potatoes are found in only one color.

Fact: The outer skin is found in more than one color. Different varieties of sweet potatoes skin are found in yellow, purple, brown or white. The flesh can vary from orange to white to purple.

Myth: Sweet potatoes must be refrigerated.

Fact: Sweet potatoes don’t need to be refrigerated. If stored in a cool, dark place, they should be used within a week. If stored in ideal conditions including a dry, dark place and around 55 degrees F, sweet potatoes can be stored for three to four weeks.


1 sweet potato, medium

Brown sugar, 1 teaspoon

Butter, 1 tablespoon, melted

Preheat oven to 400 degrees. Pierce sweet potato with a fork multiple times. Place in oven and bake for 45 minutes. Cut the sweet potato in half and then drizzle with butter and sprinkle brown sugar on top.

Corinne Labyak, a registered dietitian nutritionist and associate professor in the Department of Nutrition and Dietetics Flagship Program at the University of North Florida. Contact her at [email protected]

These are the sweet potatoes that you roast for meal prep, use for Thanksgiving sweet potato pie or marshmallow-topped mashed potatoes, and snack on as fries and chips. They’re versatile, easy to find, and the varietals within the orange-fleshed potatoes are all “pretty much interchangeable,” says Heck. She notes there will be “subtle differences in flavor, sweetness, and moisture” between Beauregard (brown skin, more deeply sweet, grown in Louisiana), Garnet (red skin, more like pumpkin flavor), and Jewel (coppery-orange skin, mildly sweet and earthy, California-grown).

Heck argues that sweet potatoes should be your new vegetarian meat replacement because they “can carry spices in a way that other vegetables can’t.” Standard white potatoes’ flavor would be obliterated by a heavy seasoning from Spanish paprika, black pepper, and garlic, but it works perfectly as a bacon-ish flavor in her Cobb salad recipe (pictured above) or with cumin and coriander for tacos.

White Sweet Potatoes

Treat white sweet potatoes like russets and fry ’em. These ones are served with ricotta and scallions.

Gentl & Hyers

White sweet potatoes may look like russets, but they’re loaded with some of the same fiber and vitamins that orange sweet potatoes have—though not as much beta-carotene. Since they’re a little drier in texture, Heck suggests using them for gnocchi so you can control the amount of moisture in the dough. For non-pasta applications, Heck says they go really well with bright, acidic sauces like chimichurri. The texture is more toothsome than mushy when roasted, but if you braise them low and slow, they end up being silky yet still hold their shape.

Purple Sweet Potatoes

Sambal-buttered purple sweet potatoes.

Kristin Teig

Purple sweet potatoes have super amped-up anthocyanins like blueberries, which are great for both color and antioxidants. The North Carolina-grown Stokes varietal are the most popular (with a sweet chestnut flavor), but you can sometimes find Hawaiian Okinawan potatoes with purple-speckled flesh that are best boiled whole. To prevent the color from bleeding out when cooking, Heck suggests roasting, sautéeing, or frying purple sweet potatoes. One of Heck’s favorite ways to eat them is topped with sambal butter. You can either make your own sambal paste with chiles, garlic, ginger, lemongrass, lime zest, and salt, or just mix 1 Tsbp. sambal oelek with a stick of butter. As it melts into your potato, all your problems may melt away too.

Related: 25 Sweet Potato Recipes to Try

Kristin Teig

Reprinted from Sweet Potatoes. Copyright © 2017 by Mary-Frances Heck. Photographs copyright © 2017 by Kristin Teig. Published by Clarkson Potter/Publishers, an imprint of Penguin Random House, LLC.


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It seems like my family nearly lives off of sweet potatoes.

In a clean eating household these root tubers are like dessert, even without the added brown sugar. And if we go more than a few days without including them in a meal, we notice.

So, if you’re looking for a garden crop that’s nutritious and indulgent, sweet potatoes are the answer.

At breakfast, lunch, and dinner, this easily stored warm-season edible is delicious and versatile.

And although it requires a good amount of space in the garden, it’s a relatively easy crop to grow.

Photo by Amber Shidler.

Last May, I purchased six slips, popped them in a raised bed, and admittedly paid little attention to them.

Come September, I had more than 30 medium-sized root tubers. I will definitely be growing these delicious beauties again this year.

To get even better results, keep reading. I’ve dug into the details about what it takes to grow this amazing root crop for the best harvest possible. Here’s what’s in store:

How to Grow Sweet Potatoes

  • What They Aren’t
  • Getting Started
  • Ideal Growing Conditions
  • Pests and Diseases to Know About
  • Minimal Effort, Large Reward

What They Aren’t

It’s important to realize that sweet potatoes (Ipomea batatas) aren’t related to regular potatoes (Solanum tuberosum) or yams (Dioscorea sp).

They are a tropical plant, hardy only in zones 9 through 11, and are actually a relative of the morning glory.

Ornamental varieties are sold nationwide for their attractive, colorful leaves.

The edible part of the plant is an enlarged storage organ that forms on the root, referred to as a root tuber. Irish potatoes, on the other hand, are stem tubers.

This is why methods for growing sweet potatoes and Irish potatoes are very different.

For Irish potatoes, you encourage the stems to develop through a method such as hilling. But with sweet potatoes, it’s all about encouraging root growth.

Getting Started

Sweet potatoes rarely flower outside of their native range so they are generally propagated from slips, or new growth that sprouts from the ends of the root tubers.

If this is your first attempt, it’s best to order slips from a nursery or trusted purveyor, since they are less likely to carry diseases.

In subsequent years, you can use your own parent plants to start new slips. To avoid diseases, think about purchasing new slips every three years or so.

There are a ton of tutorials out there on starting slips, but I’ll just share one option with you:

In early spring, move a healthy parent potato to a warm place. Soak the entire tuber in warm water overnight about a month before your area’s last frost date.

Then, find a container large enough to fit the number of potatoes you want to use. I stuck a single potato in a loaf pan and it was the perfect size.

Feel free to get creative with your container. You can use whatever is handy that’s the right size.

Photo by Amber Shidler.

A deep seed tray is fitting if you’re trying to sprout more than one.

Fill the container just an inch or two with a mixture of potting soil and sand.

Photo by Amber Shidler.

Place the sweet potato into the container horizontally and cover it with soil. It’s okay if it peeks through the soil a bit.

Keep the soil moist and warm, and wait for slips to form. This will likely take a few weeks, and you can expect to get at least 6 per tuber.

Photo by Amber Shidler.

Once the newly formed slips are at least 4 inches long, carefully break them off.

Photo by Amber Shidler.

One of the benefits of sprouting sweet potatoes in soil rather than water is that slips tend to have pretty well formed roots from the start.

Photo by Amber Shidler.

If you don’t find this to be the case, however, you can root them in water. Fill a glass with just a couple of inches of clean and, ideally, chlorine free water.

The bottom inch or two of the slip’s stem should be submerged, while the leaves stick out of the top.

Photo by Amber Shidler.

Within a week, they will develop roots and be ready to plant out in the garden, given that all chance of frost has passed and the soil temperature is around 70°F.

You’ll want to get them out in the garden as soon as possible because, depending on the variety, plants will require 90 to 120 days to mature.

Without a long growing season, chances are you’ll be disappointed with your harvest. If you’re desperate for more time at the end of the season, try using floating row covers.

Ideal Growing Conditions

Sweet potatoes are pretty tough. The one thing they won’t tolerate, however, is cool weather. Even the slightest frost will take them out.

But they handle heat and drought really well.

Still, the better the growing conditions, the better the harvest.

Being a root crop, soil health makes a big difference. Slightly acidic soil with a pH between 6.0 and 6.5 is ideal.

Sandy loam that’s well draining but nutrient dense will make this sun-loving tropical vine happiest.

Photo by Amber Shidler.

Raised beds are a great option too, since they warm up quickly and are typically filled with a loamy soil mixture. Loose soil will allow roots to grow freely.

Add fresh organic compost a week or two before planting, for added nutrients and organic matter.

If you prefer chemical fertilizers and don’t want to have your soil tested, stick with an N-P-K (nitrogen, phosphorus, potassium) ratio of 5-10-10.

Keep in mind that too much nitrogen will result in vigorous vines, but a small harvest.

Photo by Amber Shidler.

Space plants at least 24 inches apart to give vines adequate room to sprawl. Keep them well watered until they become established.

Apply a layer of organic mulch, such as pine bark or grass clippings, which will help to retain soil moisture and temperature, as well as reduce weeds.

Once vines start taking off, you can assume they’re established.

Containers work well, too, but don’t try to cram a small area with too many slips. If you do, you’ll dramatically decrease the number of tubers that develop per plant.

Instead, plants with enough room to grow produce a much larger harvest.

In the absence of rain, water regularly. Even though plants will tolerate drought, your harvest will be larger if they aren’t subject to water-related stress.

If allowed to wilt, root development will likely suffer.

About three weeks or so before harvesting, stop watering. Overwatering at the end of the season can cause tubers to split.

Once vines fill in, weeds will have a harder time becoming established. Avoid cutting vines back if possible.

If space is an issue, consider growing a more compact bush variety.

If you live in an area that has mild summers, try laying heavy-weight garden fabric over the soil to increase temperature.

Raised beds warm up faster and are especially appropriate if cooler temperatures are common.

You can also consider laying black plastic over the area in spring to get soil temperatures up.

Pests and Diseases to Know About

Underground pests might be the worst of them all because you often don’t know they’re a problem until harvest time.

What a disappointment when you go to harvest, only to find your crop has already been a meal for underground dwellers.

If growing plants in an area that was recently growing grass, wireworms (the larvae of click beetles) and root knot nematodes might already be present. Both of these critters like to munch on the tubers.

Keep an eye out for any vines that are stunted or yellowing. It may be worth digging a bit to do some investigating if you suspect underground pests.

Crop rotation, cover crops, and planting in raised beds where soil material is more controlled can help to prevent infestation by soil-dwelling pests.

Tiny holes in the leaves may be the work of flea beetles. If vines are healthy and vigorous, they should be able to handle some damage.

Sweet potato scurf is a somewhat common disease, resulting in black spots on the skin of tubers. Although it might be unsightly, it doesn’t really affect the quality of the crop. Remove the affected skin and eat them just the same.

Choose disease resistant varieties and healthy slips from the start, and provide adequate growing conditions, and you likely won’t experience any disease issues at all.

Minimal Effort, Large Reward

Overall, sweet potatoes are a forgiving crop to grow.

And, even if you only get a small harvest your first season, you can save one or two tubers as parent plants for next season.

In this way, you’ll need to spend very little money while honing your sweet potato growing skills.

Learn more about harvesting and storing your sweet potatoes here.

This long-season, heat-loving tropical is beautiful and low maintenance. And the delicious, easy to store root tubers are a satisfying reward for minimal effort.

Have you grown sweet potatoes before? Fill us in on your secrets to a guaranteed harvest below!


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Photos by Amber Shidler © Ask the Experts, LLC. ALL RIGHTS RESERVED. See our TOS for more details. Uncredited photos: . With additional writing and editing by Allison Sidhu.

About Amber Shidler

Amber Shidler lives in Cincinnati, Ohio and holds a dual bachelor’s degree in botany and geography. For four years she worked as a horticulturist, but is now a stay-at-home mom. With experience in landscape design, installation, and maintenance she has set her sights on turning her tenth-of-an-acre lot into a productive oasis. Amber is passionate about all things gardening, especially growing and enjoying organic food.

Sweet potatoes are tender, warm-season perennial plants grown as annuals.

  • Sweet potatoes require a long, warm growing season, usually about 4 months of frost-free weather to reach harvest.
  • Set sweet potato starts or slips in the garden after all danger of frost has passed, usually 4 weeks after the last average frost date in early summer.
  • Sweet potatoes grow best where the air temperature remains very warm, from 75° to 95°F throughout the growing season.
  • Sweet potatoes are best started indoors as early as 12 weeks before they are placed in the garden.
  • Sweet potatoes require from 100 to 150 days to reach harvest.

Planting Sweet Potatoes

Where to Plant Sweet Potatoes:

  • Plant sweet potatoes in full sun.
  • Grow sweet potatoes in loose, well-worked, well-drained loamy or somewhat sandy soil with aged compost added.
  • Prepare the planting bed by adding aged compost and aged manure or a commercial organic planting mix across the bed then turn the soil 12 inches deep.
  • Soil that is overly rich in nitrogen will produce more foliage than tubers.
  • Remove all soil lumps, rocks, or other obstacles from the planting bed; if tubers hit an obstacle as they develop, they will grow deformed.
  • Sweet potatoes prefer a soil pH of 5.0 to 6.5.

Plant sweet potatoes in the garden four weeks after the last frost in spring.

Sweet Potato Planting Time:

  • Set sweet potato starts in the garden after all danger of frost is past in spring, usually about 4 weeks after the last frost.
  • Sweet potatoes are extremely sensitive to frost and need a warm, moist growing season of as many as 150 days.
  • Sweet potato slips can be started indoors as early as 12 weeks before they are transplanted into the garden.
  • Well-rooted sweet potatoes require a soil growing temperature of 60° to 85°F and an air growing temperature of 65° to 95°F.
  • Sweet potatoes will thrive in air temperatures as high as 100°F.

Sweet potato slips can be started indoors as early as 12 weeks before they are transplanted into the garden.

Starting Sweet Potato Sprouts or Slips Indoors:

Grow sweet potatoes from rooted sprouts, called slips, taken from a mature tuber. Here are two ways to start sweet potato slips:

  1. Place the sweet potato in a jar of water that is half full with about one-third of the tuber submerged. Leave it in a warm (75°F), sunny location where it will sprout. When sprouts are 6 inches long, pull them off the tuber and set them in water or damp sand; they will root in a few days. Start this process about 12 weeks before you plan to set the slips in the garden.
  2. Place cut pieces of a tuber moist sand or light growing medium with a constant temperature of about 80°F. (Use a heating mat with a thermostat to keep the soil consistently warm.) Each piece must have one or more “eyes or sprouts. Set each piece 2 to 4 inches deep in sand or light soil. Shoots will appear in about 3 weeks. When shoots appear, add another inch of sand or light soil. Do not let the growing medium dry out. When sprouts reach 3 to 4 inches tall reduce the soil temperature to 70°F and grow on for another 3 weeks. Seed tubers will be rooted in about 6 weeks and can then be planted in the garden.

You can start slips in one-gallon containers or in a hotbed. If you plant in a hotbed space slips 3 to 4 inches apart.

One sweet potato tuber can yield as many as a dozen slips.

Protect tender sweet potato leaves from the direct hot sun for five days after planting.

Planting Sweet Potatoes in Garden:

  • Set rooted slips in the garden on mounded rows 12 inches wide and 8 inches high; space rows 3 feet apart; plant slips at 12 to 18-inch intervals.
  • Plant slips so that the sprouts grow up toward the sky, not sideways. Be sure to cover all of the roots and about a ½ inch of the stem.
  • Protect tender sweet potato foliage from the direct hot sun for five days after planting. Set a floating row cover over the plants.
  • Grow 5 sweet potato plants for each household member.

Companion Plants for Sweet Potatoes:

  • Grow sweet potatoes with other root crops: beets, parsnips, and salsify.

Container Growing Sweet Potatoes:

  • Grow a single sweet potato plant in a box or tub that is at least 12 inches deep and 15 inches wide.
  • Use a light, porous soil mix.
  • Place a stake or trellis in the center to support the vine which grows up and outwards.

Caring for Sweet Potatoes

Watering Sweet Potatoes:

  • Sweet potatoes will tolerate dry soil once established but will produce best if kept evenly moist, an inch of water every week (1 inch equals 16 gallons) until 3 to 4 weeks before harvest.
  • Do not overwater sweet potatoes; tubers will rot in soil that is too wet.

Feeding Sweet Potatoes:

  • Add aged compost or commercial organic planting mix to planting beds before planting. Aged compost contains all the nutrients sweet potatoes need to get started.
  • Feed newly planted slips with a B-1 starter solution or compost tea.
  • Add a low nitrogen fertilizer (5-10-10) to the soil two weeks before planting.

Maintaining Sweet Potatoes:

  • Sweet potatoes are easily trained onto trellises, lattice, or wires strung between sturdy poles.
  • Keep weeds away from young plants. Mulch around plants with loose straw or chopped, dried leaves to control weeds and slow soil moisture evaporation.
  • Pull weeds by hand or cultivate shallowly to avoid disturbing roots. Eventually, the foliage of the maturing sweet potato plant will shade out new weeds.

Sweet Potato Pests and Diseases

Sweet Potato Pests:

  • Insects are not likely to attack sweet potatoes in northern regions. In southern regions, sweet potato weevils and wireworms are common pests.
  • Weevil larvae chew holes in tubers and adults chew holes in leaves. Control adult weevils by knocking them from plants and crushing them or spray with pyrethrins.
  • Plant resistant varieties.
  • Where heavy infestations occur remove all plants and do not re-plant in that area for three years.

Sweet Potato Diseases:

  • Sweet potatoes are susceptible to root rot and fungal diseases including a fungus disease called scurf.
  • Plant disease-resistant varieties and keep the garden clean of debris and weeds where pests and disease can harbor.
  • Remove and destroy infected plants immediately before the disease can spread to healthy plants.
  • Scurf is a fungal disease that grows on the skin of sweet potatoes. The skin develops shallow purple or grayish-brown lesions. Prevention is the best control. Plant certified disease-free slips. Rotate sweet potatoes out of an infected bed for three years.

Lift sweet potato tubers when they have reached full size, commonly when leaves and vines have begun to yellow and wither.

Harvesting and Storing Sweet Potatoes

Harvesting Sweet Potatoes:

  • Sweet potatoes require from 100 to 150 days to reach harvest.
  • Lift sweet potato tubers when they have reached full size, commonly when leaves and vines have begun to yellow and wither.
  • Carefully dig plants using a garden fork starting about 15 to 18 inches from the center of the vine and working inwards lifting. Tubers will be 6 inches or so deep in the soil. Be careful not to cut or bruise the tubers which are thin-skinned.
  • Complete the harvest before the first frost in fall; tubers are damaged by freezing or cold weather.

Storing and Preserving Sweet Potatoes:

  • Cure (dry and harden) sweet potato tubers for 10 to 15 days after harvest. Set them in a warm spot (about 80°F) out of direct sunlight. Curing will help heal nicks and cuts and harden the skin. Curing will also improve the sweetness of the tuber.
  • Sweet potatoes will store at 55° to 60°F in a dry, cool, well-ventilated place for 4 to 6 months.
  • Store sweet potatoes unwashed. Wrap the tubers in a newspaper when you store them; don’t let the tubers touch or they may rot.
  • Do not refrigerate or store sweet potatoes at temperatures below 50°
  • Sweet potatoes can be frozen, canned, or dried.

Sweet Potato Varieties to Grow

Sweet potato tubers are described as “dry” and “moist” noting the texture of the tuber when eaten. “Moist” sweet potatoes are often called yams; however, the true yam is actually a different species found in tropical regions.

About Sweet Potatoes

  • The sweet potato is a tender vining or semi-erect perennial plant grown for its swollen fleshy tuber, similar to an elongated potato.
  • Tubers grow underground from the vine’s central shoot.
  • Tubers vary from creamy-yellow to light brown to deep red-orange in color and from 4 or 5 inches to 8 inches or more in length.
  • The flesh of the tuber is yellow or gold.
  • The flower of the sweet potato is pink to purple colored.
  • Botanical name: Ipomoea batatas
  • Origin: Tropical America and the Caribbean

More tips: How to Harvest and Store Sweet Potatoes

How to grow sweet potatoes in a home vegetable garden

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Growing sweet potatoes is fun and easy, and a great way to enjoy super-sweet tubers that taste so much better than those you’ll find at the local supermarket. If you’re wondering how to grow sweet potatoes in your home vegetable garden, I’ve got all the information and advice you need to get started.

Homegrown sweet potatoes are better than any you’ll find in a supermarket. And, they’re an easy-to-grow, low-maintenance crop.

Sweet potato or yam?

There’s been some confusion about yams and sweet potatoes, so let’s set the record straight. Yams are a tropical crop grown mainly in the Caribbean and Africa. The yams I see in my local supermarket generally have brown, bark-like skin and white flesh that is starchy, like a white potato, when cooked. The roots vary in size and color, with some yams growing small and others getting several feet in length.

The confusion between yams and sweet potatoes comes from the fact that for many years orange-fleshed sweet potatoes were incorrectly called yams. Sweet potatoes tubers have tan, pinkish, purple, or red skin and flesh that may be orange, white, or purple. The tubers have tapered ends and a delicious sweet flavor.

Now that we’ve cleared that up, are you ready to learn how to grow sweet potatoes? Read on!

Choosing sweet potatoes to grow

Traditionally, sweet potatoes have been a crop grown in warmer climates, but thanks to plant breeders who have been selecting for fast maturing sweet potatoes, we now have a wonderful selection of cultivars that can be grown in short-season gardens. However, you still need around 100 days of frost-free weather to grow a bumper crop of sweet potatoes.

I’ve had great success with short-season varieties like Korean Purple, Beauregard, and Georgia Jet, but there are many cultivars to choose from in seed and speciality catalogs. Just keep in mind that you won’t be ordering seed potatoes, as with potatoes, but instead will be buying slips. Slips are the shoots that grow from a sweet potato. You can also start your own slips or buy them from a garden centre in spring to plant in your garden.

It’s easy to root your own sweet potato slips or you can order them from a mail order company or buy them from a local garden centre.

How to grow sweet potato slips

Starting your own slips isn’t difficult and you can use a sweet potato from last year’s harvest, from the grocery store (see my advice below about this though), or the farmers market. Look for blemish and disease-free tubers. Depending on how many plants you want, you’ll likely need a few sweet potatoes for slip starting. Each tuber can potentially grow several dozen slips.

Once you’ve got your sweet potatoes, there are two main ways to produce slips:

  1. Stick toothpicks in the top third of your potato and set it in jar filled with water so the bottom two-thirds is underwater.
  2. Place the whole sweet potato on its side in a pot, seeding tray, or shallow container filled with a pre-moistened, high-quality potting mix. Fill the container so the potting mix covers the bottom half of the sweet potato.

Place your jars or containers of sweet potatoes in a bright, warm spot and wait. The slips typically emerge in a few weeks, but it may take as long as two months. This means you need to plan ahead and start your sweet potato slips about two months before you intend to plant them in the garden.

Preparing sweet potato slips for planting

Once the slips are six to eight-inches long, they can be broken off and transplanted into the garden (they’ll likely have some baby roots attached). If it’s not yet time to move them to the garden, pot them up in four inch pots filled with moistened potting mix. You can also put the just-clipped sweet potato slips in a jar of water so the bottom half of the stem is underwater. If there are no roots, they’ll emerge in around a week. Change the water often to promote healthy root growth.

You do need to harden off your sweet potato slips – just as you would harden off seedlings that were grown indoors under lights. To do this, you can introduce the mother plant gradually to outdoor growing conditions about a week or two before you want to snap off the slips and plant. Or, if you are removing the slips and potting them up until it’s time to transplant, you can harden off the rooted slips beginning about a week before you want to move them to the garden.

Sweet potatoes need loose, well-drained soil to produce large tubers. They can be planted in garden beds or containers, if you’re short on space.

Buying sweet potato slips

I generally buy my sweet potato slips from a reputable grower like Mapple Farm because I don’t have a good cold spot to store my garden-grown sweet potatoes over the winter and I don’t like to use sweet potatoes from the grocery store. Why? Most grocery stores don’t list the variety of the sweet potatoes they carry and with such a wide range of maturity times – from 100 days to 160 days – I want to make sure I’m growing a sweet potato variety that has time to mature in my short season garden. If I order from a mail order company or buy them from a local garden centre, I can ensure that I get varieties suited to my climate. Alternatively, head to your local farmers market and if they’re selling locally grown sweet potatoes, go ahead and buy those for your slips.

How to plant sweet potatoes

Rule number one is don’t rush sweet potato slips into the garden. They need the weather – and soil to be warm. I usually plant them around the same time I plant my cucumbers and melons which is about a week or so after our last expected spring frost. If the weather is still unsettled, wait or install a mini hoop tunnel over the bed to shelter the slips.

Preparing the soil for sweet potatoes

The key to a good crop of large tubers is loose, well-drained soil. Plant your sweet potato slips in a garden bed that has been loosened and amended with compost. Sweet potatoes are relatively light feeders but they do appreciate phosphorus and potassium, and so I work in a little balanced organic vegetable fertilizer before I plant. Avoid high nitrogen fertilizers which promote foliage growth, but often at the expense of tubers.

There are a few heat-loving crops that really appreciate you taking the extra step of pre-warming the soil, especially if you live in a short season or cold climate. I like to pre-warm the soil for my melons, peppers, eggplants, and sweet potatoes. This isn’t hard to do, but it really pays off! To pre-warm the soil, lay a piece of black plastic mulch on top of the garden bed for two weeks before planting. I usually time it so that I put the plastic out about a week before the last expected frost date.

Once you’re ready to plant you can remove the plastic mulch or leave it in place and cut holes for the slips. If you choose to leave it on the soil, it will continue to keep the plants warm and reduce weed growth. Run a soaker hose underneath the mulch to make watering a snap.

How far apart to plant sweet potatoes

Wondering how far apart to plant sweet potatoes? They should be spaced twelve to eighteen inches apart. If growing them in raised beds, I plant on 18 inch centers. In a traditional in-ground garden, leave three feet between rows to allow room to tend the crop. If you’re short on space, you can also plant sweet potatoes in containers or fabric bags. Just be sure to keep an eye on soil moisture as container dry out quicker than garden beds.

To encourage healthy growth and a bumper crop of sweet tubers, irrigate sweet potatoes regularly during the summer.

How to grow sweet potatoes

Once your sweet potato slips have been planted in the garden, water them well and continue to irrigate the bed daily for the first week if there has been no rain. After they’ve adapted to their new home, you can reduce watering, but keep in mind that drought-stressed plants yield fewer and smaller sweet potatoes. If you’re not growing them under a black plastic mulch, mulch plants with straw or shredded leaves to reduce the need to water.

Expect the newly planted sweet potato slips to sit for a few weeks as they put on root growth. Once the heat arrives, the vines quickly take off. If the spring weather experiences a setback and cold temperatures are in the forecast, cover your plants with a row cover to insulate them.

How to harvest sweet potatoes

Be patient, growing great sweet potatoes takes time. I plant 90 to 100 day cultivars and don’t even bother trying to sneak any tubers before that 90 days has elapsed. Generally the crop is harvested when the vines are blackened by frost. Dig the sweet potatoes with a garden fork, being careful to not skewer your tubers.

While you can grow sweet potatoes in containers, you’ll get a larger harvest and bigger tubers when the slips are planted in garden beds with deep, loose soil.

How to cure sweet potatoes

Once you’ve harvested all your sweet potatoes, it’s time to cure them. Curing allows the flesh to sweeten up and heals small wounds or cracks on the skin for long-term storage. Proper curing requires warm to hot temperatures and high humidity. If you can, place the tubers where it’s 85 to 90 F with 85% humidity for a week. This can be difficult in a home garden, but I’ve heard of gardeners who use an oven to cure sweet potatoes.

If you only have a small amount of tubers and don’t plan on keeping them more than a few months, quick cure them at 75 to 80 F over one to two weeks. Store cured sweet potatoes in a cool, dark basement where the temperature is around 55 to 60 F.

Did I answer all your questions on how to grow sweet potatoes? If not, leave your questions or comments below.

You may also enjoy these related posts:

  • Grow potatoes in small spaces with these 7 easy steps
  • When to harvest potatoes
  • The best vegetable gardening books to get you growing

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