Planting the Sweet Potato Slips

I kind of left you hanging there with the whole sweet potato slips thing.  Sorry about that but I was busy.  I couldn’t tell you what I was busy with, all I know is that “I was busy” is a good all around, cover your bases, excuse for pretty much anything.  Plus … I am always busy.  Everyone is.  Even if you’re just watching staring at your cat, you’re still busy.  You’re busy staring at your cat.

I think I was busy avoiding doing my taxes.  That’s a kind of busy there’s no escaping from. I washed my pencils, inspected my arm hair, and did all manner of incredibly important things. Anything that allows me to avoid doing my taxes is incredibly important.

So. That’s my explanation as to why you haven’t got your “How to Plant Sweet Potatoes” instructions yet.  Don’t worry about it though, because if you’re around my zone (6) then you’re still in the window of planting time.

Sweet Potatoes slips shouldn’t be planted until the weather and soil are WARM.  June 1st is the day I usually plant them, this year it wasn’t until June 5th.

To add extra warmth to the soil you should put down black thermal plastic to help heat up the soil a couple of weeks prior to planting. Even if you can’t get it down 2 weeks before planting, put it down whenever you can. Even if it’s the day you plant.  The black plastic helps keep down weeds, retain moisture as well as increases the temperature of the soil by 10 degrees.  That’s just enough degrees to increase your chances of growing great big sweet potatoes by 100%.   That’s obviously a percentage I made up to encourage you to put down the black plastic but trust me, you should do it. I’m 100% sure of it.

If you don’t have access to “official black thermal mulch”, just use a black garbage bag or two.  Amazon even has biodegradable black plastic mulch for just $15, which is less than I paid for my regular black plastic mulch.  And it’s enough to last you for years of sweet potato growing.

I used 5 or 6 sweet potatoes to create my slips this year. I had NO idea how many slips this would produce but as it turns out it created 14 million.    Maybe not quite but definitely over 100. Most of which I sold at my community garden sale, and 25 or so that I kept for myself.

I also ordered 12 sweet potato slips this winter from an online source in case my slips didn’t work.  So this year I’m planting the 12 I bought and the 25 or so that I grew myself.




Technically sweet potato slips don’t even need roots on them to plant them. You can just snap them off the sweet potato and stick them in the ground.  This slip has a couple of little roots but nothing impressive. Just make sure you water right after planting them.


To plant them just  cut a hole in your plastic, stick your finger in the soil and stick your slip in. Then pack the soil around the slip so it has contact with the dirt.




You can plant 1 sweet potato slip per square foot.  My bed is 8′ long by 4′ wide, so I planted …. (I’m just getting out my calculator now) … 32 sweet potato slips.  Generally speaking, you’ll get 1lb of sweet potatoes per square foot, so this bed should yield 32 lbs of sweet potatoes.



This little thing in the photo above is one of the sweet potato slips I ordered through the mail.  It’s sad and thin looking but it’ll eventually become huge so I’m not worried about it.  This is how sweet potato slips always look when you order them in the mail.




On the other hand, this is one of the sweet potato slips I grew myself.  Much healthier, much fuller and therefore much better. Also it was free which makes it the best. Chances, are they’ll both end up the same size by the end of the year with the same amount and size of sweet potatoes though.



This on the other hand is an experiment of mine.  After my sweet potato slips grow, I put them in water to root. Some of them were in water for 2 months!  So I took 2 of them and potted them up to see if they would grow significantly more in soil than in water while I was waiting for the weather to warm up enough to plant them.

Yup.  The potted ones grew 5x as big.





This shot gives you a better comparison between the sweet potato slip I grew in soil compared to the rooted slips I bought online. So clearly this one has a way better head start on the other ones.  I’ll check at the end of the year to see if there’s any appreciable difference in the size of crop between them.

[print_this]How to Plant Sweet Potatoes

1.  Lay black thermal mulch (plastic) on area for planting 2 weeks before setting out.

2.  Cut a circle in the plastic and push one slip in.  Make sure the slip has contact with soil all around.

3.  Plant 1 slip per square foot.

4.  Harvest sweet potatoes before the first frost.  Once the weather cools down they won’t grow anyway.

5.  Cure you sweet potatoes according to the instructions in this post for optimum sweetness.[/print_this]

I’m also trying sweet potatoes in big black containers this year as an experiment for an article for Lee Valley (which I write for).

So I’ll let you know how that goes.  Probably 2 weeks too late, probably because I’m busy, probably because I’m avoiding something.

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  1. Dette says:

    Hi, when harvesting sweet potatoes, do I leave the sweet potato plant with it’s roots back in the soil or pull them and discard them after? I’m a newbie gardener.


    SE Ohio, raised bed taters!

    • Julie B. says:

      Those are simultaneously frightening and beautiful. You should definitely be proud! I have been duly inspired by your example and this blog’s directions on growing, so I’ve just started sprouting my very first SP’s. Starting with a small patch, then hopefully I’ll go buck-wild like you! Cheers.


    Our raised bed taters, using “MEDINA HASTA GROW” bought on Internet. Zone 6, S.E. Ohio


    Raised beds!! Loose soil definitely was a key
    We added Sandy lo to loosen our soil. Go on line and you can buy “MEDINA HASTA GROW.” Fertilize with it mixed in a bucket of water; I do bi-weekly. Be prepared, this stuff makes EVERYTHING GROW CRAZY!!! Our raised beds have about 20″ of loose soil. I ran the house down spout underground to the bed in a perforated drain pipe and covered with gravel, then straw, then black tar paper, before filling the bed. Works fantastic!!!! Yum, pass the brown sugar!

  5. cheryl seals says:

    THANKS KAREN, Now i know what to do with the 2 sweet potatoes that are on my window sill in laundry room, they started growing leaves all by themselves in the pantry ,alas i moved them to window ! Poor lost in the pantry sweet potatoes…I shall be giving them a new home in the ground any day now, it’s still June so i’m good…hehe

  6. Malia@Small Town Girl Blog says:

    That’s really cool! Great tutorial. Pinned :)

  7. Jan in Waterdown says:

    Don’t know if this question has been asked before, so apologies in advance! I assume that those pretty lime green or black leaf sweet potato plants sold at the garden centres for decorative purposes are non edible? They produce huge roots in the pot and in the past I’ve been tempted but didn’t want to die!

    • IRS says:

      Jan, I ate the tuber at the bottom of my garden centre, lime green, sweet potato when I tossed the plant at the end of the summer. This was about 4 years ago, and I’m still here! It was quite tasty, and I had no stomach ache, etc. It never even occurred to me that it wasn’t edible. Maybe I will be more cautious in the future, but I doubt it. :D

  8. Amy says:

    We planted ours in big plastic buckets (like keg buckets) last year and we’re STILL eating the potatoes we grew. It worked perfectly! You’re awesome, hope all of your potatoey dreams come true!

  9. Shirley says:

    I just planted my first slip today. The others didn’t have roots yet but now I see that doesn’t matter so I will stick those in too. It will be fun seeing what comes of them.

  10. Laura Bee says:

    My kid ate so many potatoes when she was a baby I thought she would turn orange. I had a cousin that happened to – all my aunt could get him to eat was carrots.

  11. Erin says:

    I am really interested to hear how the slips that went into soil compare to the ones grown only in water.
    That could really give us northern gardeners an edge raising sweets.
    Thanks for keeping busy!

  12. Mary W says:

    Black plastic is used to kill what is under it here in Florida. Got the humidity and temperature correct though to cure them just laying on the ground outside. I grew and ate SP for years but never knew that about the sugar cure. I did however, find out about the fat cell storage system LOL. Quit gardening, start cell storage. That is why I love your blog – I always come away with something knew – spelled new but for knowledge. Know what I mean Vern?

  13. Valerie says:

    Thank you Karen for all of this information. My slips grew perfectly. Years ago I obtained a “sweet potato vine” that had beautiful pink flowers. I scoured the internet in a search to see if there is a different type of bulb or tuber that produces this plant but was unsuccessful. Will the slips that I grew from my grocery store sweet potato produce flowers and if so do you recall if they are pink in colour?

  14. Catherine Vosper says:

    Do you have any experience or tips re planting horse radish?

  15. Ella says:

    Thanks, Karen! I’ve been following your instructions and just planted mine in the soil! I can’t wait! I got about 30 slips off of ONE sweet potatoes! I love multiplying food. Makes me feel like Jesus! lol!

  16. Tigermom says:

    Taxes. Yuck.

  17. Ann says:

    Something I think I should mention. Sweet potatoes do better in very very loose soil. Doesn’t have to be particularly fertile tho. The best crop I ever had was when I layered leaf mulch which we had gotten for free by the pick up truck load full, with plain garden soil. This year they are growing in raised beds that were filled with the compost that came from sitting a year in the chicken run. It started out as leaves, kitchen waste, grass clippings, weeds, and anything we had that we could throw into the chickens. And of course, what the chickens added themselves.

    Every year that we have planted sweets into our basic garden soil, we had only so-so yields. Any time we made sure to use extra loose soil, we had crops that could have helped feed a starving small country. And it sure makes them easy to harvest. You can almost reach down, find the original stem coming out of the soil and pull the entire plant out of the ground. We had had at least 1 football sized sweet potato off each plant along with dozens of very good sized tubers and then some smaller ones that we just throw into the chickens to pick at. Even the super big roots are tasty and tender, although they can be a bit hard to prep for cooking!!

    Don’t bother fertilizing sweet potatoes. Like I said above, they don’t need it. And down where we are, black plastic will be cooking the soil by May.

  18. Phyllis Kraemer says:

    Are the sweet potatoes growing in the pots that are in the first photo?…or are they special pots that are bigger than those…if not…what is in those pots please?

    • Karen says:

      Those pots have a combination of experiments. 4 have regular potatoes, 2 have sweet potatoes and 2 have tomatoes. I’m doing an experiment with watering and not watering tomatoes to test their sweetness levels at the end of the summer. ~ karen!

  19. Teresa Jennings Richardson says:

    I don’t know if you do this or not, but once the sweet potatoes start producing vines, we would make sure they also made contact with the soil, put a little on top to hold it in place and you get extra potatoes where that vine roots. We usually did that after a nice rain so we could pull any tall grass or weeds out at the same time, then we left the patch alone to grow babies until fall. The vines keep the soil shaded so weeds didn’t have much of a chance to grow. Sweet potatoes were always a favorite crop of mine. No hoeing, no hot summer work. As the commercial says, “set it and forget it” til fall. Harvesting Sweet potatoes was always one of my favorite jobs. We had an acre sized patch for our family of 7 and daddy plowed them up with his old John Deere tractor. It was a true treasure hunt for us all that day and after the next big rain. Just like an Easter egg hunt, there are always one or two that got missed. We usually found about another bushel or so .

    • Phyllis Kraemer says:

      What a great story Teresa!…thanks!

    • Karen says:

      I have a love hate relationship with digging potatoes and sweet potatoes! That’s why I’m also trying some in huge pots this year to make harvesting a bit easier. Just dump the bucket! ~ karen

      • brenda says:

        I think I might do a couple in buckets too now … and I really like that tip about putting the vines in soil and getting more and more … and more

        I love them pureed …

  20. Sherry in Alaska says:

    Being in an even colder zone (9 or 10) depending on the year…… I may try this next summer in hay bales. In the meantime, I’m watching to see your results.

    • Sherry in Alaska says:

      Oops! Got that really backward. I’m in zone 3 to 4………… maybe. Depends on the year and how hardy a plant is. Like you – recommended planting date is 6/1….. On 6/1 this year we woke to snow falling and covering the ground. After a week that ran into the 80s F….. So I still intend to try this next year.. Just needed to set the zone thing straight.

  21. Jeannette says:

    My question is this: what are you going to do with all those sweet potatoes after you harvest them? Do they really last an entire year in storage or are you eating sweet potatoes morning, noon, & night in an effort to avoid wasting them? My daughter & I love sp, but 3 meals a day would get tiresome quickly, I would think. I often get sweet potatoes in my CSA box, and find myself trying to give a lot away, much like a bumper crop of zucchini.

    • Karen says:

      I’ll use and give them all away. My mother loves sweet potatoes so she’ll get a few. I used them primarily for sweet potato fries but also like to bake them. If cured and stored in fairly good conditions they’ll last until next March/April. ~ karen!

      • Paula says:

        I don’t grow them for lack of space but I buy lots of them from a local farmer. I bake them,wrap in plastic wrap or foil and throw in the freezer. Last year the hubs and I ate 30 pound of them darn things. We are a little addicted to plain old baked sweet potatoes.

    • David says:

      We live in Georgia and harvested our crop in October. We ate some and packed the rest away. We used them off and on over the winter. I had them in a dry spot where they will not freeze and they lasted until April. I packed them in a box with layers of crumpled paper between the layers. A few of the smaller ones did shrivel, but they were no great loss. We’re getting ready to sprout the healthy looking medium to small ones.
      Some of my friends from the Philippines were surprised that we do not eat the leaves, as they eat them in soup.

  22. brenda says:

    alrighty then … mine need to go in now … YAY – thanks Karen.

    I only did one potato but I got at least 10 really healthy sprouts from it and there’s still one growing from the top of the potato’s head. AND I remembered to put down two garbage bags on my soil last week … so YAYAYAYAYAYAY … I am ready to do this.

    I will take pictures and post on Twitter once it’s done. I’m in the High Park allotments (I think that’s zone 6-ish-y-ish).

  23. dana says:

    Those plants in the little top less canning jars are so cute. Can I save a few as houseplants? I’m also zone 6.

    • Karen says:

      Hi Dana. Yup! People grow sweet potatoes as a house plant all the time but I’ll warn you, the vines can get many, many feet long, lol. ~ karen!

    • Rondina says:

      We use sweet potatoes as plants for tall containers and ground cover. They’re really pretty. (Zone 7-B)

  24. Claudia says:

    I knew that I’m not the only one who tries to avoid doing the taxes!
    (Usually I begin several times, and when approaching the deadline, I get so fed up with it all that I just throw all of the bills and forms in an envelope and mail it – come what may.)
    So, caring for the sweet potato slips seems like one (of many) pretty good excuse for avoiding the taxes… ;-)
    Thanks for sharing!

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