How to Grow Sweet Potatoes From Slips

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Digging up sweet potatoes

This time of year, some of the prettiest produce on the shelves at my local organic market are sweet potatoes (Ipomoea batatas). Unlike many other crops, the quality of sweet potatoes improves in storage, so they taste better now than they did in November. But as their dormancy period ends and sweet potato tubers begin to sprout, growing sweet potatoes from slips (rooted cuttings) becomes a fun springtime project.

But wait. Aren't sweet potatoes a tropical crop, difficult to grow in cool climates? Yes and no. In recent field trials in chilly New Hampshire, for example, fast-maturing varieties like ‘Beauregard' and ‘Covington' produced three to four nice tubers per plant when planted into black plastic mulch, which helps warm the soil. In the UK, these and other vigorous varieties often are successful grown under plastic-covered tunnels. Still, you will get a bigger harvest when growing sweet potatoes in a warm climate than a cool one. In warmer climates, gardeners sometimes harvest eight or more tubers per sweet potato plant.

My own climate is a bit cool for sweet potatoes, but I still grow them because they are delicious, nutritious, easy to store, and grow like crazy in unusually warm summers. They also require little care, because vigorous sweet potato vines knit themselves together into a tangle of foliage that shades the soil and suppresses weeds. Besides, I wouldn't want to miss out on the drama of having sweet potato vines growing in my windowsills in late spring.

Growing sweet potatoes in a pot

From Tuber to Sweet Potato Vine

Sweet potatoes are grown from rootable cuttings, often called slips. If you've never grown sweet potatoes before, it can be great fun to grow your own slips from small or medium-size sweet potatoes purchased at the market. One sweet potato will produce between three and five slips. This process takes about six weeks, so there is no need to hurry. At the Sand Hill Preservation Center in Iowa, Glenn Drowns emphasizes the importance of planting sweet potatoes after the weather turns warm and stable, in early summer. In my garden, the soil is not warm enough for sweet potatoes until the middle of June.

As a kid, I had fun sticking toothpicks around the middle of promising-looking sweet potatoes so I could suspend the other end in a jar of water and thereby grow a robust vining plant. This method works when conditions are right, or the result can be a scummy rotting sweet potato. A better idea is to nestle a sweet potato tuber diagonally in a bed of moist potting soil, with the sprouting end pointing up. Kept warm and lightly moist, the tuber will quickly sprout shoots that leaf out into vines. As the shoots, or slips, grow to 6 inches (15 cm) long, they can be broken off and transplanted to the garden, or to containers if outdoor conditions are too cold.

You can buy bundles of sweet potato slips if you are growing sweet potatoes in a big way, or you can use the bucket of sand method. Fill a bucket halfway with damp sand, and then lay in several sweet potatoes, half buried in the damp sand. Keep the bucket in a warm place, and it will be overflowing with slips in four to six weeks.

How do you tell the sprouting end from the root end of a sweet potato? This is not always easy, but the end of the tuber that was closest to the mother plant is fertile ground for foliar buds. If you cannot see little reddish buds on either end of a sweet potato, simply place the tuber in a warm place for two weeks. Buds will emerge, and you will know which end should go up.

Sweet potato sprouts

Handling Sweet Potato Plants

Sweet potato slips that are grown indoors should be gradually exposed to strong summer sun over a period of one to two weeks – a task most easily accomplished by placing the mother plants in warm filtered shade. Prior to planting, the slips are snapped off, along with the lowest leaves. The slips are then positioned diagonally in well-moistened trenches, which are refilled so that only the top two leaves are showing at the surface. As long as the soil is kept lightly moist, the slips will develop roots and start growing within two weeks. Six weeks after that, the sweet potato vines will explode with growth and cover the ground with dense foliage.

Even the fastest-maturing sweet potato varieties should be allowed to grow for 90 days before you start looking for harvestable roots. It is also important to dig sweet potatoes before soil temperatures cool too much, because various skin diseases often develop in cold, moist soil. Some sweet potato varieties set tubers quite close to the primary growing crowns, while others wander a bit before initiating tubers. If you are not sure what to expect, begin digging from the outside of the row to minimize broken tubers.

Sweet potato leaves

Fresh sweet potatoes need to be cured for two to three weeks in a warm place. During this time, wounds to the skin heal over, and the flesh becomes sweeter and more nutritious. This process continues after curing, during the first months of storage at cool room temperatures, so stored sweet potatoes that are eaten in winter are often the best ones of the year.

The fastest-growing sweet potato varieties have orange flesh, but varieties with white, yellow, or even purple flesh are excellent options if you have a long, warm growing season. Sweet potato varieties vary in texture and flavor, though it can generally be said that orange-fleshed varieties cook up moist, white sweet potatoes become remarkably creamy, and purple sweet potatoes are dry and starchy, like regular potatoes. If you see these and other unusual sweet potatoes at local farmers markets, they are worth trying in your garden, too.

By Barbara Pleasant

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Comments

 
"Fantastic information. I am trying to grow them but no luck so far. I got organic sweet potatoes from stores, hanging them in water in warm, light place, but no luck so far. Only 4 weeks have passed. Let's see if it does anything in the next two weeks. "
KL on Friday 1 March 2013
"what about using potato grow bags in a warm location in your garden? has anyone tried sweet potatoes using this method?"
Terry on Friday 1 March 2013
"Great article. I have just planted my second row of slips and my original potato still popping out more. I am using a japonese sweet potatoe. It began showing roots within three days of being suspended in water. I then put it in a plastic bag and it took an airline flight and I popped it back in a glass and slips started coming within two weeks. It is summer here in the tropics so quite warm, but it was winter where I started it. "
LR on Friday 1 March 2013
"I planted 40 slips last season. I harvested about 50 lbs of tubers. Cured them for 4 weeks and now we are enjoying them a couple of times a week. My place is in central Ontario Canada."
James Wylie on Saturday 2 March 2013
"Terry, I have seen pictures of sweet potatoes grown in large grow bags, but have not done this myself. Sweet potatoes prefer a firmer soil than regular potatoes, so they may be prone to curve more in bags filled with soft soil. You will get tremendous foliage, however, which is ornamental in itself. Young leaf tips are edible as cooked greens, too."
Barbara Pleasant on Monday 4 March 2013
"hi, i'm from bc canada. can i grow sweet potatoes here?"
marie hallam on Saturday 9 March 2013
"British Columbia is a big place, and it's possible that some of the mildest coastal areas would do. However, you will be better off growing fast-maturing winter squash as your fail-safe orange-fleshed storage crop."
Barbara Pleasant on Monday 11 March 2013
"I am in Northwest Mass and I have grown sweet potatoes for years with no problems I always have a great harvest we still have two milk crates full and I have given tons away!!! I order my slips online thru a sweet potatoe grower and have been very happy with the plants"
Michelle Douglas on Tuesday 19 March 2013
"I live in central Ontario (Peterborough) Canada. Just started growing sweet potatoes last year. I tried 2 varieties. Georgia Jet was the best. Forget the name of the other. They were fun to grow and we did get some tasty meals out of the 12 slips we planted. The biggest problem with them is digging the tubers. They really do spread out away from the center of the plant snd deep. Bit of a treasure hunt. Anyway we are plsnting SP again this year. Trying 2 more cultivars to see if they are better than the Georgia Jets. "
Bill in Ontario Canada on Wednesday 20 March 2013
"I'v got 1 big sweet potato shootin shoots without water its just sittin in a foam box near a fridge can't wait 2 plant them n barta with them with a stall market I barter "
kim from QLD Australia on Sunday 28 April 2013
"I have been growing sweet potatoes outside in potato bags in Yorkshire, UK. I was told they like a warm climate so I grew them initially in the green house, but they're outside now and doing better than ever. I have given them canes to grow up and they seem to like this. "
Marie on Sunday 11 August 2013
"Hello Marie from Yorkshire, was great to get information on growing in Yorkshire, where did you get your slips from, what sort where they? Have you tried to grow your own slips? N. R another Yorkshire Gardener"
N. R on Monday 7 October 2013
"Hi can.t wait grow some sweet potsin the new year .i want the best and easy way to grow them"
Linda on Thursday 31 October 2013
"hi,ive never grown sweet potatoes before but im going to give it a try and we will see what happens. 5 spuds in the greenhouse just waiting to emerge. west midlands."
malcolm ditchburn on Friday 14 March 2014
"Im gona try some there in water at mo im in Wiltshire UK plant them in a sand sawdust and soil mix at my allotment"
Sam on Saturday 24 January 2015
"Do you live in the peterborough area and do you sell slips or do you know a local farm that does. Tks."
Steven on Tuesday 24 May 2016
"I live in sub tropical Australia, where it is easy to grow sweet potatoes. I bought organic tubers of different varieties 18 months ago and confined them to raised garden beds for ease of digging up. I'd had no success with starting slips from shop bought sweet potatoes, and discovered this was because of the treatment to inhibit shooting. The organic ones worked well. From that time on, there was no problem. Any piece of vine shoved in the ground would produce a new plant. They also grew from pieces left in the ground after harvesting, and everywhere I threw a few bits of vine on the lawn, and forgot to pick up, there is now a sweet potato vine. They take much longer to mature than expected - up to a year for a good crop. But while we wait, the leaves are delicious in stir frys."
Linda on Tuesday 4 April 2017
"Thanks for your interesting report, Linda. Hope you harvest a great crop of sweet potatoes!"
Barbara Pleasant on Wednesday 5 April 2017

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