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Sweet Potato

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Botanical name: Ipomoea batatas

Plant type: Vegetable

USDA Hardiness Zones: 9, 10, 11

Sun exposure: Full Sun

Soil type: Loamy

Soil pH: Neutral


Flower color: Purple

Bloom time: Summer

The sweet potato is a warm-season, spreading vegetable of tropical origin. It is a good choice for a garden because it is easy to grow, is drought- / heat-tolerant, and has few pests or diseases. The sweet potato is also very nutritious and low in calories.

Planting

  • Sweet potatoes are grown from slips, which are sprouts that are grown from stored sweet potatoes. You can buy slips from garden centers, nurseries, or local farmers.
  • You can also grow your own slips to plant in the spring. In November (this is when the best of the new harvest will be out), go to your supermarket and look for unblemished and uncracked medium sweet potatoes. One potato should yield about 12 plants.
  • Store these potatoes in a well-lit room with a temperature between 65° and 70°F. Keep them there until about 90 days before the last spring frost date. They will then need to be embedded in soil for 90 days and kept continuously warm and moist.
  • Use a 1-1/2 gallon pot for every two potatoes. Remember to poke drainage holes in the bottom of the pot and fill it with 3 inches of mulch followed by garden or potting soil. Plant the potatoes in the pot at a 45° angle so that the sprouts will grow above the soil. When the slips are 6 to 12 inches tall, you can plant them outdoors as long as all danger of frost has passed.
  • After you have grown your own slips or bought them, till area of the garden you will be using to a depth of 8 to 10 inches. Create raised beds 6 to 8 inches tall and about 12 inches wide. Use fertile, well-drained soil.
  • Plant the slips 12 to 18 inches apart in the bed, after the last spring frost date. Plant the slips deep enough to cover the roots and about 1/2 inch of the stem. Water the slips with a starter solution that is high in phosphorous, then water generously for a few days to make sure that the plants root well.

Care

  • Side-dress the potatoes 3 to 4 weeks after transplanting with 3 pounds of 5-10-10 fertilizer per 100 feet of row. If you have sandy soil, use 5 pounds.
  • Hoe the beds occasionally to keep weeds down. Remember to reshape the beds with soil or mulch.
  • For good harvests, do not prune the vines, because they should be vigorous.
  • Remember to keep the potatoes watered. Deep watering in hot, dry periods will help to increase yields, although if you are planning to store some of the potatoes, do not give the plants extra water late in the season.

Pests

  • Flea beetles
  • Sweet potato scurf
  • White blister
  • Fungal leaf rot
  • Stem rot

Harvest/Storage

  • You can start digging up the potatoes as soon as they are big enough for a meal. Often, this is three to four months from when you planted the slips. The leaves should have started to yellow, but you can leave them in the ground up until the fall frost.
  • Since the roots spread 4 to 6 inches deep in the soil, a spade fork is useful when digging up the potatoes.
  • Handle the potatoes carefully because they bruise easily.
  • After digging up the potatoes, shake off any excess dirt but no not wash the roots.
  • If you want to store sweet potatoes for an extended period of time, you must cure them. Curing the potatoes allows a second skin to form over scratches and bruises that occur when digging up the potatoes. To cure, keep the roots in a warm place (about 80°F) at high humidity (about 90%) for 10 to 14 days. For best curing, make sure that the potatoes are not touching one another.
  • After curing, throw out any bruised potatoes, and then wrap each one in newspaper and pack them carefully in a wooden box or basket.
  • Store the sweet potatoes in a root cellar or other place with a temperature of at least 55°F. The ideal temperature range is 55° to 60°F.
  • The roots should last for about 6 months. When removing the potatoes from storage, remember to be gentle; do not dig around or else you will bruise the potatoes.

Recommended Varieties

  • 'Centennial', which is one of the most popular types of sweet potato. It is carrot-color and has a good storage life. It is also a good producer for northern growers.
  • 'Jewel', which is copper-color and has good disease resistance. It also has a good storage life.
  • 'Bunch Porto Rico', which is a good choice for gardens with limited space. It is copper-color and very flavorful.

Recipes

Cooking Notes

To the cook, sweet potatoes are easier than pie.

  • They can simply be scrubbed, poked with a fork in a few places, and baked at 400°F for 35 minutes to one hour, until they give a bit when you squeeze them in your pot-holder-protected hand.
  • In the microwave, a whole sweet potato baked on high should be ready in 4 to 6 minutes. It may still feel firm when done; let it stand 5 minutes to soften.
  • Sweet potatoes can also be steamed whole, cleaned and unpeeled, for about 40 minutes or until tender, or cooked whole, cleaned and unpeeled, in boiling salted water for about 35 minutes. (Boiling reduces the flavor considerably.)
  • Immerse cut raw sweet potatoes in water until you're ready to cook them; they will darken otherwise.

As a general rule, don't substitute sweet potatoes for regular potatoes in recipes; the two aren't related. Sweet potatoes don't hold together the way potatoes do, and their strong flavor can overwhelm a dish meant for a milder potato taste. But they make a fine substitute for pumpkin, especially in desserts.

Wit & Wisdom

Sweet potatoes will retain their color if cooked with a slice of lemon.

Comments

I live Nashville TN planted

By Jeanette Harris-Johnson on October 14

I live Nashville TN planted sweet potatoes
June vines, not yellow are they ready to dig small bed. Planted beside squash have removed squash bush. Sweet potato vines still blooming

Hi, Jeanette: You can dig

By Almanac Staff on October 14

Hi, Jeanette: You can dig them up if you want to, but we'd leave them in the ground until the end of the month -- or until you get word of your first frost coming up (which is usually about October 28). But beat the frost, and be gentle.

My first harvested sweet

By gigiof6 on October 13

My first harvested sweet potatoes have very dark patches on their skins even after washing; when scraped with a fingernail, underneath is bright orange. Wassup with this coloring? Is it just the variety I planted and are they still edible?

We have grown sweet potatoes

By Ellie McLeod on October 8

We have grown sweet potatoes for the past 2 years here in SC. Started with slips from store bought potatoes and this past year slips from last years crop. We are fascinated with the sizes and shapes of the yield. Everybody gardening should try planting them at least once. My first bed was 10 feet by 4 feet. Vines were everywhere so allow for this. We just dug up some and got two huge potatoes that looked like swans on the same vine. They weighed over 2 lbs each. Get the kids involved in the digging.

I have just dug my sweet

By Janice Tyler on September 30

I have just dug my sweet potatoes and would like to know if there is anything I can do to the soil to prepare for my next years planting? Jan in Iowa

I bought a huge sweet potato

By Lynda Provenzano

I bought a huge sweet potato that weighed around a pound and wasn't able to cook it when I had planned. It grew quite a few "eyes," one of which was about 6" long when I found it hidden in a corner of the kitchen counter. I cut about an inch and a half off the end of the potato and put it in the ground under a bank of low windows about 10' long. I watered it from time to time all summer when I watered my grape vines and other backyard flowers. That vine is now about 2' wide and a foot high and has wrapped around the end of the house by about 3'. My husband just told me he sprayed that 3' section with RoundUp. The rest of the vine, all on the ground, had put on a dozen flowers. 1) Will the RoundUp on that end kill the whole vine? 2) If I cut that part of the vine off would the rest of ot be safe from the RoundUp? 3) Do you think there would be any sweet potatoes under the vine? 4) If it's safe, should I dig up anything or wait to see if the vine is going to live since there is so much of it? There are some purple leaves around where I originally planted it, and only one yellow leaf in the same spot. Can you advise me?

Since round up in made to

By DebbieA on October 27

Since round up in made to send the killing ingredients to the root of plants & that is what a sweet potato is a root. I would say nice try till hubby destroyed it but no don't continue dig & throw away! ASAP

Just leave the vine as is, no

By Almanac Staff

Just leave the vine as is, no need to cut anything off. You can harvest as soon as the leaves turn yellow, but some gardeners wait until after the first frost to dig the potatoes. The longer the potatoes are left in the ground, the higher the yield and vitamin content.

My mother was growing a sweet

By Helen Miles

My mother was growing a sweet potato plant in her yard and it was so beautiful that I was considering planting the ones I have sitting on my kitchen counter, with the plan to keep them as a houseplant. Is this too crazy? I have two very large pots for this plan.

Hi, Helen, Lots to talk about

By Almanac Staff

Hi, Helen, Lots to talk about here. First, the sweets on your counter, presumably from a grocery store, may have been treated with a sprout inhibitor (some potatoes are, too). You might seek out organic ones, ideally something that has started to send out slips—roots. If you can't find one of those, choose the freshest, least blemished one/s you can find.
Here's one option: Put the sweets into a warm, dry paper bag and see if any roots develop.
Or try this: Do not cut a sweet into pieces to plant. Instead, plant the entire organic tater (this step you could  try concurrently with the bag, if you have enough sweets) in potting soil. It should sprout slips. When these reach several inches in length, you can cut them and a piece of the "mother" tater and plant separately.
You can also put the narrow end of the tater into a glass of water, holding the sweet in place on the rim by prodding it with toothpicks. Put it in the sun, and in about 10 days you should see growth at the bottom. For long green foliage to develop, cut off all of the weak slips/roots, leaving 2 or 3 strong ones, and plant it in potting soil.
Sweets indoors or out like warmth.
Good luck!

Hello. We have been growing

By Taryn

Hello. We have been growing sweet potatoes for the past 5-6 months now, and we have noticed that the plant is flowering above the ground. Is this okay, and do sweet potatoes actually grow above ground like pumpkins as compared to below like potatoes?

Sweet potatoes grow under the

By Almanac Staff

Sweet potatoes grow under the ground. In most areas, you dig up the potatoes around the time of the first frost in the fall. Some varieties flower though it's not common in most U.S. regions. The flowers attract pollinators which are a good thing!

Hi! I'm in Tucson Arizona and

By Grace Bean

Hi! I'm in Tucson Arizona and bought 2 Ruby Red ,cut them up and tossed in the ground. Now a month later the plants are a 1-2 ft. Combo with some vines that are taller than me ...with a grasshopper problem. What r my chances, tips? And with 2 pets how can I get these lil buggers to go away? Thanks!

Hi, Grace, Sources tell us

By Almanac Staff

Hi, Grace, Sources tell us that the best control of grasshoppers for a small crop such as your is hand picking, that a variety of natural enemies—bee flies, blister beetles, ground beetles, spiders, rodents, birds and disease—should keep them in check.
The last two pages of this Cochise CountyMaster Gardener newsletter from Nov 1999 describes the problem in particular in your vicinity:http://ag.arizona.edu/cochise/mg/pdf/Nov99.pdf You might also contact them for specific information.
You might also read and contact the source quoted, as he is in your area. According to this, your sweets should be thriving. We don't know what might be the challenge (in addition to the 'hoppers). http://post.uanews.arizona.edu/blog/sweet-potatoes-vs-yams
Finally, hope for a very cold winter. That would destroy the eggs.

My five year old put a sweet

By Genna

My five year old put a sweet potato in water and roots have sprouted, can we plant this now?

The sweet potato needs to

By Almanac Staff

The sweet potato needs to develop slips, not just roots. Please see the planting advice above.

My sweet potatoes are showing

By Darlene Cannon

My sweet potatoes are showing above ground. What should I do,can I cover them up and wait or dig them up? The variety that I planted is beuregaurd.

Hi Darlene, If the tops are

By Almanac Staff

Hi Darlene,
If the tops are still green the potatoes are still growing. We suggest that you cover them up with soil and wait another month before checking to see if they are ready to harvest.

When you mention "tops" does

By Christy Huffman

When you mention "tops" does this mean the vine or the root? Thank you.

"Side-dress" Not familiar

By Daniel Casey

"Side-dress" Not familiar with this word or term. What does this mean?

Also, I've read the vine leaves are stable and actually ate one. Although their taste is starchy, it was tender and mildly flavored.

Does the vine produce more sweet potatoes as it grows?

How much room or slips does it take for enough potatoes to feed a family of 4 for a month?

:)

Sorry Correction "Stable" to

By Daniel Casey

Sorry Correction "Stable" to Edible...

"Side-dress" means to apply

By Almanac Staff

"Side-dress" means to apply fertilizer on or in the soil near the roots of a plant.
 
Sweet potato leaves are edible to humans, but regular potato leaves are not (different plant family). Sweet potato vines are listed by the ASPCA as toxic to dogs, cats, horses, and some other animals.
 
The plant may form tuberous roots (the sweet potatoes) along the length of the vine in sections that have developed normal roots. A tuberous root is a thickened modified root, and contains buds on one end, which will develop stems and leaves in the spring; the other end will form tiny roots.
 
As for how many to plant, it depends on how many sweet potatoes your family will eat. :-) Sweet potatoes will yield about 8 to 12 pounds per 10-foot row.

8 - 12 lbs per 10' row? I

By Rich in Arkansas on October 24

8 - 12 lbs per 10' row? I planted just one sweet potato plant (Beauregard)in north Arkansas and it yielded 30 lbs. One of the potatoes was 6 lbs. I've always found them to be exceptionally prolific.

Wow! That's a lot of sweet

By Almanac Staff on October 24

Wow! That's a lot of sweet potatoes from one plant. 'Beauregard' is known to be high-yielding and you must have the right growing conditions.

I put potato in a cup and

By nancy luse

I put potato in a cup and it is growing long vines. Can this be planted and how.
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I put sweet potato in a cup

By nancy luse

I put sweet potato in a cup of water and it is growing long vines from it. Can it be planted?

Yes, break the vines off at

By LivinLifeAgain on October 7

Yes, break the vines off at the potato, place in a jar & let it root, then plant. They are called slips.

When is a good time to start

By Joseph Mukura

When is a good time to start growing sweet potatoes in the uk

im sorry if i seem dumb, does

By gill

im sorry if i seem dumb, does the potatoe grow above ground on plant or in the ground like long island potatoes

No worries. Sweet potatoes

By Almanac Staff

No worries. Sweet potatoes grow under the ground. 

I live Ontario and am

By henryenn henr.enns@gmail.com

I live Ontario and am trying to grow sweet pototes for the first time. We have always enjoyed them in recipes and as sweet potato fries .

Thanks for the info. I have

By Patsy Olive

Thanks for the info. I have learned a lot today. Thank you. Patsy

Sweet Potato thrives very

By Bisiriyu O.Afolabi

Sweet Potato thrives very well in my locality Offa,Nigeria and it's environs.Could you kindly connect me to interested growers or business partners who may be keen in investing in massive growth of Sweet Potato in Nigeria.
My future plan is to cultivate Sweet Potato and turn into it's various nutritional values such as flour,chips,noddles and other food items.Thank you.

Thanks for the information

By Wesley Miller

Thanks for the information and looking forward for more info

If the temperature should be

By Jeremiah Tamez

If the temperature should be between 55 and 60 F what should the humidity be during long term storage.

Sweet potato roots are stored

By Almanac Staff

Sweet potato roots are stored between 55 and 60 degrees F with high relative humidity (>90%) for a storage life of 6 to 10 months.

I bought one little plant at

By LIANE

I bought one little plant at a plant sale just to try it in our climate---Powell River, BC Canada. I know it has potatoes as they came out of the ground and I hilled them up. The vines are really growing. Will they put down more roots and then more potatoes? Can I protect the vines over our usually pretty mild winters and keep the whole thing going or do I need to start over in the spring?
thanks, this is exciting.

Depending on the variety,

By Almanac Staff

Depending on the variety, sweet potato vines are hardy in zones 8 through 11. The vines will not survive in cold weather, but in climates free of frost, the tubers should survive the winter and sprout new vines come spring.

Please help me. I LIVE IN

By OVID P. MERCENE

Please help me. I LIVE IN SOUTHERN cALIFORNIA AND HAVE PLANTED SWEET POTATOES. DURING THIS WINTER THE PLANTS LEAVES HAVE TURNED YELLOW AND LEAVES DIED?. aRE THEY DEAD OR SHOULD I JUST LEAVE THEM THERE AND COME SPRING THESE VINES WILL SPROUT NEW LEAVES. PLEASE HELP I DON'T KNOW WHAT TO DO WITH THEM. THEY'VE SPREAD ON MY BACKYARD WITH ALL LEAVES NOW YELLOW THIS WINTER. SHOULD I JUST LEAVE THEM ALONE? PLEASE SENT ME THE ANSWER ON MY E MAIL. THANK YOU.

Did your field get hit by

By Almanac Staff

Did your field get hit by frost? If so, it's possible that they died. Look at the vines. Are they green/alive or brown and dead? To be safe, you may want to dig up the sweet potato tubers if they are in good shape and store for spring growing and prepare your soil for replanting.

Why do plant seeds grow on a

By Luv u

Why do plant seeds grow on a 45* angle???
Plz answer fast because my science fair depends on this

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