This post is part of a series of educational articles on gardening, self-sufficiency and food independence. That’s what The Liberty Garden is all about. To find out more about the mission behind The Liberty Garden concept, go here. Or read all the archives.
As far as vegetables go, sweet potatoes are my favorite, and thankfully, they are extremely nutritious. In 1992, the Center for Science in the Public Interest ranked the sweet potato as the number one king of all vegetables in terms of nutritional value.
In addition to being nutritious, sweet potatoes are easy to grow, typically yield well at over one pound per plant, and do not require refrigeration for long-term storage. What a great recipe for food security.
Personally, I have had success growing (and eating) the following varieties: Beauregard, Carolina Ruby, Centennials, and Jewel.
Sometimes people get confused about the difference between sweet potatoes and yams. Botanically sweet potatoes are broad leafed plants in the same family as the morning glory and in the genus Ipomoea. Yams on the other hand, grown primarily in Africa, are a member of the Lily family and in the genus Dioscorea. The confusion came about in the 1950’s when a few marketing folks in Louisiana thought it would be a great idea to call their new orange-fleshed sweet potatoes “yams.”
Preparing
To successfully grow sweet potatoes you will need a frost-free growing season of 100 days (or more). Most sweet potato varieties need this length of time from the transplant of a sprout (or “slip”) until edible tubers can be harvested.
Assuming that you have an adequate growing season, your next consideration is whether to grow your own slips or to purchase them. If you decide to grow your own, it takes approximately 6 weeks before the slips become big enough to transplant.
To grow slips, select a few small sweet potatoes and soak them for several hours in water. Place the soaked potatoes in a large flower pot ½ full of dirt. After adding the potatoes, cover them completely with 2 inches of dirt. Keep the flower pot indoors in a sunny spot and well watered. Each potato will produce 10 to 15 sprouts which will have roots near the potato. When it is time to transplant the spouts, simply take the potatoes out of the pot and break off the individual spouts.
It may be possible to purchase slips at your local garden center in early summer or you can order them via the internet. One company that I have had excellent success with is Steele Plant Company in Tennessee. Even if you do not purchase slips from Steele, you may want to check out their page describing the characteristics of different sweet potato varieties.
Planting
Sweet potatoes grow best in loose, sandy, well drained soil (well drained is an absolute must for success). My strategy is to plant slips in raised beds with a center ridge 10-12 inches higher than the surrounding area. Each slip should be planted at a depth of approximately 2-3 inches (with the leaves sticking above the ground). Within a row, you can plant successive slips every 12 to 18 inches, but keep your rows about three feet apart so that the plants have adequate room to spread out.
After transplanting, you will need to water each slip immediately and do so every few days until the plants have established themselves. Typically you do not need to irrigate the plants after they are established unless you live in an area with limited rainfall.
Weed early and often as this allows the vines to produce large tubers that do not have to compete for nutrients. When the plants get fairly large, they will shade out any new weeds that might try and emerge. About one month after transplanting, I would suggest that you side-dress each plant with a generous amount of compost (a spade full on each side of the plant).
Lastly, with respect to planting, you will absolutely need to protect your sweet potato vines from deer if they tend to be a problem in your area. Speaking from experience, it is extremely frustrating to have a beautiful bunch of sweet potato vines one day and nubs the next morning.
Harvesting
You will need to judge your harvest date primarily based on the suggested growing time for the variety you have chosen. In most cases the number of days will be 90 up to 120 days. When I harvest, I pull up the vines first and pile them out of my way. In some cases a few of the potatoes may come up with the vines, but that is not typical.
I dig my potatoes with a pitch fork, but a shovel or spade should work fine as well. The key is to dig far enough away from the center of the vine (as most of the potatoes will be in a 12-18 inch radius of the center). Dig down about 6 inches and angle your shovel or pitch fork toward the vine center and gently lever up. The potatoes should lift out of the ground. If your soil is really loose, you can also use your hands.
Try not to leave the freshly-dug tubers exposed to the sun for more than one hour.
Storing
The most important part of the post-harvest process is called “curing.” Before you eat your trophies, you need to keep them in a hot, humid, dark area for approximately two weeks. For curing, I store my potatoes in 20 gallon tubs (not too deep) and keep them covered with damp towels in the garage.
After harvesting and curing your potatoes, keep them stored in a cool area in your home (and protected from sunlight). I typically am able to keep my September harvest potatoes until March of the following year.
Good luck. And please ask questions if you need more information.
Photo credits:
Great post! Since converting my eating habits from white potatoes over to sweet potatoes, I’ve been wondering if we can grow them up here in the northern states. Glad to know that there are 100 day varieties.
When the vines start to grow out of control, don’t forget that the prunings are edible, raw or cooked.
http://nutritiondata.self.com/facts/vegetables-and-vegetable-products/2664/2/
Great point Keith! And the vines will be thriving in the hottest part of the summer when most other greens have bit the dust.
I am just growing my first batch of Sweet potatoes. In a 4 foot by 4 foot raised garden. What can I plant next to them?
I am all over this! Woot!
You can buy the heirloom slips here:
http://www.sandhillpreservation.com/catalog/sweet_potatoes.html
Additionally, you can pick the maturation (e.g., early, late, etc)so those of you in harsher environs can grow SPs. If they can grow them in Iowa then you should be able to grow them in the north with a few modifications: black plastic over the soil and maybe a hoop house in the fall.
Sand Hill appears to be sold out for the season due to an unusual demand for sweetpotato slips. (Gosh, Robb and Amber, maybe because of this article!)
Where can one find a good source for different varieties of sweet potato seeds? Just curious, because I would like to try something a planting something a little less traditional.
Jeremy, I go to the organic store and buy theirs’. I put it in a glass of water with two toothpicks (or corncob holders)on either side of the potato and wait for the slips to come out. Then I put it in a glass of water to get more roots. This year I’m planting in a more controlled manner, in a barrel sawed in half, so I can find the potatoes. They sprawled and grew everywhere in my garden plot and it’s hard to dig without hitting one. Anyone got a plan on how to avoid doing that?
Awesome, I’ve been playing with the idea of trying to grow a couple kinds of japanese sweet potatoes here. Looks like it may just be that time!
Great post! I will have to try this. Maybe with purple yams.
I think the CSPI is the last org we’d want to be quoting though, if you’ve seen Fathead…
re: CSPI – I haven’t seen Fathead (but probably should), so I didn’t know about the stigma.
Check out Fathead on hulu.com or on Netflix Instant Play. A must-see. Movie maker Tom Naughton also has a great Fathead blog, too.
Tim – Great write-up! Maybe I missed it, but does anyone know where to get slips for the Japenese varieties that Robb is so crazy about? (hmm, I guess you get the slips by buying the Japanese varieties and growing slips off from them, don’t you) Next question: where to get Japanese sweet potatoes ?
Thanks!!
Thanks Allan! Growing your own slips from a variety that you have eaten (and loved) is a great way to go. I have seen some of the Japanese varieties in my local Whole Foods.
I just got The Japanese variety today at my Farmers Market in Raleigh. I understand they have white flesh.
I’m not sure where you live but I found Japanese sweet potatoes at Whole Foods. They are delish!
WHOLE FOODS!
Now there’s a blast from the past!
I got so fed up with trying to tell the ‘organic’ from the ‘non-organic’ produce that when I need to buy produce (which is seldom, since I’m a 4 season CSA farmer), I go to the local independent ‘organic’ market, where you don’t have to worry about coming home with conventional chemmie stuff.
Anyway, does anyone know if the japanese yams are there all the time or if there’s a definite season for them?
I can actually make it to a Whole Foods tomorrow and I’ll see what they have. (I’m in the DC-area)
I’ve got an email in to a California guy who is suppose to sell purple japanese sweet potatoe plants, but he hasn’t gotten back to me yet, unfortunately.
Thanks, Everyone!
UPDATE
I made it to WHOLE FOODS yesterday, the incredible new one in Rockville. Damn, what a madhouse! They had the dark Japanese sweet potatoes. I carried with me a photo of the Okinawa purple potatoes, the one that’s considered to be a ‘super food.’
http://www.examiner.com/nutrition-in-sacramento/what-are-the-five-super-foods-where-can-you-get-them-sacramento
The produce manager said that they get in purple Japanese sweet potatoes about once a year and they are sold within the hour.
In my GOOGLing for sources, I ran across this piece of information that I hope Robb incorporates in his advice to super market foragers:
Most of the purple sweet potatoes you will find in the US supermarkets and health food stores come from hawaii. All sweet potatoes that come from Hawaii are required to be irradiated.(source on request)
Irradiate sweet potatoes apparently taste as good as non-irradiated ones BUT sccording to the Organic Consumers Association:
” Irradiation can cause free radicals when the molecules of microbes break up. They can bond with other chemicals in the food, such as those from pesticides
Irradiation can affect the vitamin content of foods, lowering them by as much as 80%.
These foods may contain “trace amounts of radioactivity.”
Food irradiation can damage enzymes in food, making it harder for the body to digest. ”
All of these things make irradiated purple potatoes into something that I imagine should remain outside of the Paleo diet. I don’t know if there is such a thing as Hawaii grown purple sweet potatoes in this country that are ‘organic,’ but, apparently, even if they are organic, they have to be irradiated to come to the mainland. (Stranger things have happened, witness the ‘pastuerized’ ‘oranic’ almonds. Organic “rules” cave to higher powers readily. I just don’t know the details in this particular case.)
An additional piece of news I found was that there are two commonly sold purple sweet potatoes. One if the Japanese/Okinawan purple, which is a true super food and the other is a “Hawain” purple sweet potato which apparently tastes good but does not qualify as a super food.
Even if you are only eating sweet potatoes for carbs, I wouldn’t think you’d want to accrue the non-food by products of irradiation in your gut, but that’s not for me to say.
Another piece of “news” Sand Hill Preserve in OHIO, which offers (but does not currently have) Japanese Purple Potato plants says that they grow very poorly in OH, often do not produce a crop and are only recommended in HOT climates. Now, they don’t address greenhouse growing but they do say a very long season is necessary, which can refer to light needs as much as heat needs, so those of us with non-electric greenhouses may not do too well, either.
I’m still looking for a source for the Okinawa purple potato plants!
I’d still eat them.
Great info! Thanks Allan.
hmmm, maybe Robb is talking YAMS, here’s what I found for Japanese Sweet Potatoes, but they aren’t bragging them up like Robb does (so I don’t think they are the right ones)
http://www.farm-fresh-produce.com/spvarieties.html
Another easy trick for sweet potatoes is to grow them in straw bales. Make sure it is straw and not hay though! Stick aabout 8 sets (part of the potato with root and leaves growing out) into the bale with a small shovel-full of compost. Water the straw bale every day the first week or so and only occasionally after that. You can add more compost later in the season if it looks like they need it. When it is harvest time, just cut the strings on the bale and kick it open. You can just pick up the potatoes off the ground and they don’t need as much curing time.
Also, once the vines start growing, they completely cover the bale so it looks beautiful while they are growing.
Wow! right on. Katie, would this be a good option in cold areas? Say if you are using a green house?
I would think it would work. I’ve definitely extended the season this way, so it seems like it would work in colder areas.
That’s pretty awesome! Thanks for the tip.
What a coincidence… I just a wrote an article about the Sweet Potato and Yams differences and how to know which is which…
http://www.paleovillage.com/2011/04/19/sweet-potato-yam-which-is-which/
Hi Mike,
I went to the link you mentioned regarding yams vs sweet potatoes and your domain has expired. Is it somewhere else on the web that I could read it? It sounds interesting.
Oh, yeah, Japanese sweet potatoes are the best, hands down! If anyone knows how to grow them in the Pacific Northwest, let me know.
Growing sweet potatoes in the Pac NW? Check your micro-climate. I’m near the airport in Port Angeles and had no problems.
I simply found a sunny, not too windy, side of the house and prepared a sandy soil bed there, planted, and harvested.
Hey Dr Robb,
Since starting my paleo journey I have to say that sweet potato has been a big area of confusion to me.
I understand that yes it’s a lower GI vege. For me is a perfectly great alternative to potatoes, but is it paleo? Will enjoying it help me on my weight loss journey or does it need to be limited?
Your thoughts would be greatly appreciated.
Dr George
Doc! I tend to limit carbs in folks when they are leaning out. As you get lean then PWO carbs come in, then just find what your sweet spot is.
So when I get me a place that has a yard I am grow me some sweet pa taters! Has anyone made sweet potato taters, maybe cooked on bacon grease?
Yep, every week. I peel and slice a sweet potato (about 1/8 inch thick slices) and put them on a cookie sheet (covered in bacon grease). Put into a 275-300 degree oven for about 30 minutes (flip once halfway through). They make excellent chips!
I want to grow sweet potatoes this year for the first time. I am trying to start slips in water but nothing seems to be happening. It has been two weeks. Should I give up and order some?
Hi Mindy,
Two weeks probably isn’t long enough. If you don’t see any spouting within a total of four weeks, move on to plan B.
That said, I am not sure where you are located so if you need to get your slips in the ground in May (to have a long enough growing season), you will likely need to order them.
…Tim
so your saying the leaves themselves you can eat just as if they were salad? And as far as putting the potatoes in a tub. Do you drape the towel over the tub or lay it directly on top of the potatoes? Could I bring that same tub inside the house after the 2 weeks cure time if I don’t have a dark area to put them in?
Thanks, sorry for so many questions
Pretty great post. I just stumbled upon your blog and wanted to mention that I’ve really loved surfing around your weblog posts. After all I?ll be subscribing to your feed and I’m hoping you write once more very soon!
Just the info I was looking for! I picked up some starters at our local farmer’s co-op (Beauregard) today and wanted to check before I plant them. Great article AND comments!
Only one question:
Are there any plants that they shouldn’t be planted near? I’ve got space in a raised bed that has okra and carrots (and maybe some asparagus). Thanks!
You can cut vines and make better small baking pototoes the u do with slips.
Great post.I was wondering if sweet potatoes
could be grown in South Florida.Family favorite.
Thanks so much. Your page is very informative. I’m going to start planting tommorow. By 100 days my backyard will be full of potatoes. Thanks.
Are the vines of the sweet potato nutritional enough for livestock? I am interested in planting in Central America, (potatoes for humans, vines for goats, cattle).
why cure sweet potatoes?
Longer shelf life.
i live in guyana south america. webdo not sprout but rather we use the slips pulled out from the previous crop.
What do you mean,you use the slips pulled from the previous crop?
Does anyone know where to get kumura slips stateside? My wife and discovered these delicious tubers in New Zealand.
Kumara is the Maori name for sweet potato. They are the same thing.
Nope, not the same at all.
If you ever ate a roast kumara, you’d know (and see) the difference.
If I pull the plant up and potatoes are too small, can I replant and wait?
Whats the best time to plant the slips in Switzerland? Thanks
Can sweet potatoes be grown in a pot?… i mean for food (but maybe the foliage would be nice, too???) I don’t have a big enough area for ground-planting more than one vine anyway.
This is the first time I have grown Sweet Potatoes, I only grew 9 plants and they have covered our garden. Being anxious to see how they did, I dug up one plant. It had close to 8 potatoes.. they were very strange looking. My friend told me to use slips rather than purchase them in a 6 pack garden container or this would happen. Also, I didn’t realize they needed to be stored before eating; so I brought them in the house and cleaned them and where my knife cut through them it turned a silver/gray color.. do you think all the potatoes are bad? Thank you!
I am sitting here in January in the Pacific NW–grey, wet, cold–etc. Found your information on Pinterest–can’t wait for time to try sweet potatoes.
Great instructions, great comments, made my day.
Hoping to have raised beds and try more than one variety–I have lots of compost, my horse and my goat are great at supplying material.
I am going to spend the rest of the evening reading all the archives–just know I will learn a lot more.
Thanks to all for brightening up the atmosphere !!
Now that you have eaten the potato you should try the leaves also. They are just like spinach,also great in smoothies
I love sweet potatos! I already have a vegetable garden where I grow some veggies (my latest harvest is brussels sprouts!) and last year I had considered to grow sweet potatos, but everyone around me said that I was crazy, so I didn’t do it. But after reading your post, I will grow it this year. Last year, I grown regular potatos, so I think that the sweet ones, will grow here too, hopefully. Thank you for your sharing 🙂
How big do sweet potatoes gets?
They can potentially get pretty big. The Guinness record is 81 lb 9 oz
What kind of yields per square foot of garden space are you guys getting on these?
irish potatoes are supposedly yield around 1 lb/sq ft or better. was hoping sweet potatoes are similar.
Just knocked down my potato tower. They had small holes but no bugs. My godfather has us put wood on his garden and burn it. I think this keeps the bugs out. I use the potato tower made out of crawfish wire, hay around the outer edge and fabric on the outside. One tower had huge potatoes. Spendt more time in the ground than what was recommended. Doing it again next spring. btw it was Sweat Potatoes.
I read about growing Sweet Potatoes using slips so I got a bud vase shaped so that it would support the “Mom”, potatoe. When the slips seemed to be thriving I planted them in a pot in April and have not known when to dig them or how to dig them. Strange thing– in the same pot a mini bell pepper grew so we have been picking peppers for months and the sweet potatoe is still growing strong in that pot.I read that when the temp drops below 55 Degrees it is time to dig. SO – I have a dilemma . The weather has not gotten below 55 and I don’t like the idea of destroying the pepper .plant So do I just throw caution to the wind and dig now ?
i made a cool discovery after pouring through endless blogs on sweet potatoes. they love a heavy mulch especially woodchips with greens mixed in. when i do this with my sweets they flower prolifically.. i have started to suspect a microryza relationship possibly with ink caps.. good article ty
how Will I know how to differenciate the vines from each others?
I live in S Florida and am growing Okinawan sweet potatoes for the 1st time. It’s been 5 months and the plants are flourishing like crazy so that I had to cut the vines back as they were intruding into the neighbor’s. I cooked the greens. Better than spinach! My question is, WHEN DO I HARVEST? There has not been any flowers if that’s a sign. Also, CAN I GROW MY 2nd CROP FROM THE VINES OF THE OLD PLANTS OR DO I NEED TO START NEW SLIPS FROM ANOTHER POTATO?
Great post, bty. Thanks, Robb.
Use them in large containers to cover the feet of tall growing flowers on the patio. Harvest several medium to large potatoes per pot as bonus to enjoying the lush, draping vines.
EASY!
u
I am Anekwe,Emmanuel.
Can i plant sweet potato during the dry season,if answer is YES.How?
Check this out https://bonnieplants.com/growing/growing-sweet-potatoes/
The Okinawan’s diet consisted mainly of sweet potato, and with one of the highest numbers of octogenerians there must be a good reason why!