Potato Towers Don’t Work

Overview

  • Potato towers are a form of extreme hilling that uses a structure to add a foot or more of soil above the seed tuber.
  • Towers are not a new idea, but they have only become popular in recent years.
  • Potatoes are normally hilled up about six inches, whether they are grown in the ground or in containers.
  • Hilling up much beyond six inches brings no benefits and is likely to reduce yield.
  • The purpose of hilling is not to stimulate production of tubers, but to protect the tubers from the environment.
  • Potato yield is primarily limited by foliage area, not by the amount of soil above the seed tuber.
  • Conventional container growing works fine with potatoes but potato towers don’t work.

You have probably read about potato towers somewhere on the Internet.  The idea is immediately appealing: rather than strain your back growing potatoes in the ground, you can grow just one plant, but keep adding soil to it in layers to increase the yield.  This is essentially extreme hilling, adding 12 to 30 inches or more of soil over the top of the seed piece instead of the more typical 4 to 6 inches.  Each additional layer delivers essentially a doubling of the yield versus growing the plant in the ground.  At the end of the season, you just take the tower apart and hundreds of pounds of perfect spuds tumble out at your feet.  The only problem with this idea is that it isn’t true.  You will find no research that supports this idea.  You will also not find any photographic evidence that is not obviously faked.  The claims about the physiological basis for this idea are totally wrong.  Despite these limitations, the myth persists and grows stronger each year.  A friend called the potato tower phenomenon “the single worst piece of gardening advice that you see frequently on the Internet,” and although the Internet is chock full of terrible gardening advice, I think he is probably right because towers require a substantial investment of time and material that brings no benefits.  This post will take a look at the history of this idea and delve into the reasons why it simply doesn’t work.

Defining Failure

Before we go any further, I want to clarify exactly what I mean by “doesn’t work.”  I always get some angry responses when I claim that towers don’t work.  I am not saying that you can’t grow potatoes in a tower or even that you can’t get good yields in a tower.  I am saying that you won’t get better results with a tower than you can obtain under similar growing conditions without the additional levels of hilling.  You will almost certainly get worse results with a tower if you do perform all that additional hilling.  (Growing conditions vary, and in some climates it might still work out for you, but it will be success in spite of your efforts.)  It is specifically the claim that towers are able to produce greater yields due to the production of more layers of tubers that is wrong.  If you take that away, then a tower is just a planter and subject to all the pluses and minuses of growing potatoes in containers, which are specific to climate.

Several people have asked, quite reasonably, how we could tell if a potato tower worked as described.  I don’t want to get your hopes up, because there is really no possibility that you are going to find success with this, but it is still a useful exercise to imagine what it would look like.  Per plant yields with elite potato varieties occasionally reach 10 pounds or more under perfect conditions.  If a tower worked as described, it would be able to routinely exceed that threshold.  The tower hypothesis claims that the additional hilling allows the plant to create more tubers, so the tuber count should also be significantly higher than for a conventionally grown plant.  If you can show this kind of high yield, high tuber count combination and you can reproduce it reliably, you might have the first real tower potato.  Just don’t invest your retirement savings in this project.

Where is the Research?

I get a lot of responses to this post and one question comes up again and again: where is the research that shows that potatoes don’t form additional levels of stolons?  As far as I am aware, this has not been studied.  There is a good reason for that.  Nobody has observed a potato that grows this way.  It is kind of like asking why there aren’t more studies showing which tomato varieties form tubers.  Nobody has studied that because nobody has ever observed a tomato that makes tubers.  Science usually starts with an observation.  It would be better to ask if there is anybody who has documented a potato that does form multiple levels of stolons.  This would be very easy.  Just one picture would sort everyone out and almost certainly inspire further research.  I have grown tens of thousands of potato plants, from hundreds of accessions, modern, Andean, and wild potatoes from the whole native range of the potato.  I have never seen one that forms stolons in the way that is imagined in towers.  I have also talked to many other people with similar experience who have never seen such a thing.  You can’t prove that something doesn’t exist, but you can prove that it does.  I leave it to boosters of the potato tower to demonstrate a variety that behaves in the manner claimed.

From Tires to Towers

As far as I can tell, the potato tower began with the idea of growing potatoes in tires.  Somebody realized that you could achieve the necessary hilling quite easily by putting a potato on the ground and then filling up the tire with soil.  That works very nicely.  I’m sure it didn’t take long before someone decided to add a second tire, then a third, and the tower was born.  I’m not sure how far back that idea goes, but I’m guessing that just about as long as there have been tires, there have been people trying to grow stuff in them.  I can find references to growing potatoes in tires going back to the 1970s.  References to towers don’t go that far back, but some structures that we would now call potato towers do.  The most notable of these is a potato tower patent from 1976, from which I lifted the image above.  While the patent predates the term “potato tower,” all the elements are there and the illustration does an admirable job showing a kind of potato growth that has never been captured on photo or video.  One of the most fascinating parts of the potato tower phenomenon is how little people are deterred by its lack of reality.  There is more than one patent for potato towers and hundreds of articles, both in print and on-line.  A lot of work went into writing all that material, but apparently no testing.  That’s pretty remarkable.

The term “potato tower” first started to show up on the Internet on Usenet in the 1990s, but it wasn’t a common term.  Through the 1990s, there are more than a hundred mentions of growing potatoes in tires for every mention of potato towers.  Potato towers came into the Internet consciousness in 2006 and really started to take off in 2012.  Google Trends shows the frequency of these search terms over time:

So, fewer people are searching for information about growing potatoes in tires, but more people are looking for information about potato towers.  While spring searches for the term peaked in 2013, the overall amount of searches year-round have been pretty constant.  It doesn’t look like the potato tower myth is ready to die out on its own, unfortunately.

The Irish Eyes Type Box

Image: Seattle Times Mar. 9 2009

For the first few years, the idea shows up primarily in forums and personal blogs, but starting about 2005, it began to creep into magazines and newspapers as well.  One frequently cited article from the Seattle Times in 2005 (followed by a more popular recycled version in 2009) promises 100 pounds of potatoes in four square feet.  This idea traces back to Irish Eyes, a seed potato supplier, and appeared in newspapers across the country over several years.  In fairness, the article reports that someone who tried it produced only 25 pounds.  Assuming that they planted one tuber per square foot, that would be a yield of 6.25 pounds.  That’s on the high side vs. the typical field yield, but still well within the possibilities for growing potatoes in the ground.  This is one of the common results that you see with towers: people are very impressed with the yield, even though it is not any better than they could have expected if they grew plants in the ground with the same level of attention. 

Other than being taller than necessary, the Irish Eyes box (see right) is a reasonable enough design and the yield promises are not impossible, although few people are likely to achieve them.  By allowing the plants to grow out over the sides of a 4 square foot box, you can really expand the foliage area to around 16 square feet.  (But bear in mind that you could easily grow 16 to 20 plants in 16 square feet of ground.)  If you live in a perfect climate and put the plants on drip irrigation, you could possibly grow 13 plants in that box – 9 along the perimeter and dangling out and four growing in the center.  100 pounds divided by thirteen plants gives 7.7 pounds per plant.  That is a great yield but, again, one that can certainly be achieved growing in the ground, everything else being equal.  A Denver Post article supplies a bit more information, including the fact that the originator of this idea has achieved a maximum yield of 81 pounds.  That would be 6.2 pounds per plant, still a great yield, but well within reason.

Image: Irish Eyes via The Seattle Times

The interesting thing about this design is that it is much more elaborate than it needs to be.  There is no reason to build it up so high.  The multiple levels would lead you to believe that what happens inside the box will look a lot like the patent illustration at the beginning, with tubers forming at every level of the box.  That just doesn’t happen.  If you grow a potato like this, when you dig it up, you are going to find a very long stem and a cluster of tubers at about the level that you planted the seed piece.  This is really just an unusually tall planter.  You could do as well with a container of the same area that is only about a foot tall.

The Modern Myth

I think that we have found the origin of the modern potato tower concept, but it had not yet reached the point of unbelievability  So, when did this thing go fully fraudulent?  It is actually pretty hard to pin it down.  Starting in 2009, there were hundreds of blogs and articles per year about potato towers, offering a spectrum of variations on the story.  I read dozens of these articles and I would have to do a lot more work to establish the timeline.  It isn’t worth the effort.  One thing that I feel pretty confident about though is that most people did not set out to tell a tall tale (so to speak).  This story evolved over time, with people adding a few details here and there that they thought plausible.  If you can fault most of the people who have written about this with anything, it is not sufficiently testing the idea before promoting it.  Articles about potato towers fall into four categories: those that promote the idea and never report on results, those that later report pretty normal potato yield, those that later report failure, and those that promote the idea and then unconvincingly report success (usually in support of selling a tower kit).  An hour of research on the Internet provided a ratio of these types of articles of 74 : 11 : 9 : 2.

Peak absurdity usually comes with commercialization. I particularly like this tower that shows potatoes in the bottom and a plant growing out the top that is clearly not a potato. Photo: Walmart

The tower story has gotten a lot more refined over the years.  It now includes details like the need to add levels at a certain rate in order to force the plant to form more stolons and a requirement for indeterminate varieties in order to produce multiple levels of tubers.  These enhancements sound good.  They also might convince you that, if your tower didn’t really work, it is because you didn’t do it right.  It isn’t your failure though.  The whole idea is wrong.

Potatoes Just Don’t Grow Like That

We could spend a lot more time looking into the origins of the potato tower, but let’s cut to the chase.  Potato towers don’t work any better than growing in containers or growing in the ground, all else being equal.  All else being equal means that they get the same kind of soil fertility, the same soil temperature, the same amount of water and drainage, the same amount of soil coverage, and the same level of defense against pests.  Often, it is easier to achieve these things in a container, although sometimes the opposite is true.

There are two insurmountable problems with the potato tower concept:

  • Tuber production is limited by foliage area.
  • Almost no potatoes produce additional stolons past the first few nodes above the seed piece.

We could dispense with this idea based only on the relationship between foliage area and the total energy budget of the plant.  The main function of a plant’s foliage is to collect energy.  That energy is converted to sugars and moved into the body of the plant for storage.  This is where tubers come from.  They are little balls of captured energy and water.  Evolution does not allow for slackers.  Plants have evolved to fully use the capacity of their leaves to capture and store energy.  There is no excess energy for the plant to use to form more tubers, no matter how many stolons that you might convince it to produce.  If you somehow forced the plant to produce ten levels of stolons, then you would get 10 times as many tubers that would be 1/10th as large (actually less, because so much energy would have to be expended on the formation and maintenance of all those stolons).  If you want more yield, you need more foliage.  Nobody claims that towers produce more foliage though.

The other problem is that potatoes simply don’t produce an endless number of stolons.  Stolons are formed from the first few nodes above the seed piece and rarely any higher.  Hilling up in excess of six inches is a waste of time and effort and only makes the plant work harder.  The reason for hilling is not to make the plants form more tubers but to ensure that the tubers are covered by soil.  Tubers need to be covered to protect them from pests, diseases, and sunlight, which will turn them green and increase the content of toxic glycoalkaloids.  Plants will often survive extreme hilling, but you aren’t doing them any favors; they have to pump photosynthate and water farther, which costs the plant energy.  The greater depth of soil can also be a barrier to water reaching the roots.

A mythology has been built around the idea of the indeterminate potato as the solution to the tower problem.  Indeterminate potatoes do not produce stolons in a different way than determinate potatoes do.  Potatoes form all the incipient stolons that will become tubers in the two to six weeks following emergence.  While determinate potatoes form a certain amount of foliage, flower, and then die back, indeterminates continue to branch and flower for a much longer period of time.  The tubers and the total yield are often larger, but this is simply a result of the plant having more foliage area and more time to grow.

It is possible that these problems could be overcome through breeding.  Some wild potatoes set stolons over a larger number of nodes and also can form very long and sometimes branching stolons.  These might be convinced to grow through a larger vertical space.  Potato plants also vary considerably in size and a much larger plant would be able to collect more energy.  In combination, these traits might make for a potato that would behave more in line with the tower potatoes that have been imagined.  Even if it is possible though, it doesn’t seem like a very practical investment.  The great thing about potatoes is that they are simple to grow.  And cheap too.  Why make it complicated and expensive?  A simple container or raised bed, filled with quality soil, amended and watered appropriately, can deliver heavy yields of potato along with the other benefits attributed to towers such as easier management and harvest.

Potato towers don’t work.  They never did and they probably never will.  No doubt, the idea will persist on the Internet as long as people still grow potatoes, which will probably be a very long time.

Have you tried a potato tower?  If so, leave a comment and let the world know how it worked for you.

More Information

The Low Technology Institute is studying several different potato growing methods this year, including towers.  If you are interested in this subject, you might want to follow along.

Nathan Pierce, an admin with the Kenosha Potato Project experimented with towers for several years and documented the process at Tomatoville with lots of pictures.

25 thoughts on “Potato Towers Don’t Work

  1. Tim Springston says:

    Hey Bill, Great post. I’ve got a copy of “the Self Sufficient Gardener” by John Seymour, and there’s a sidebar illustration of this method, I think with the potatoes growing in a barrel. It definitely seems to be a fully realized version of this meme, and I suspect is was thrown in as an afterthought. The entire book seems to be a (beautifully illustrated) mish mash of different gardening systems and tips and tricks thrown together to capitalize on his self sufficiency superstardom (at that time I think the late 70s)

    I think its also worth mentioning how much hotter and drier the soil is going to be in a tower vs in ground, and how much potatoes hate to have their root systems at high temps.

    • bill says:

      Thanks Tim. That’s very helpful information. I will likely revise this article at some point and knowing more of the historical details will make it easier to track down the origin.

      The topic of growing potatoes in containers is pretty complicated, which is why I didn’t go into detail. Because they so dramatically change soil temperature and moisture levels, considerations for container growing are tightly coupled to climate. The problems that I have with growing potatoes in containers are likely to be very different than those that you experience.

  2. Curzio says:

    Not only I totally agree .. I study how well vines grow tubers vertically (almost 10 years now)! Different strains may bulk tubers set on nodes further away from the seed piece BUT I have no evidence of any decent size tubers above 14″
    THEREFORE any container taller than 16″ is a complete waste of time.

    • bill says:

      I’m glad that the Kenosha Potato Project is linked from your name Curzio. People who are interested in towers should really check out the KPP, because growing in bags offers a lot of the same benefits but without the hyperbole.

  3. John Reed says:

    I have tried to grow potatoes in a tower three times. Only the last time did I achieve any sense of success but it simply reflected what you stated in your article. One layer of potatoes and a meager harvest. I also attempted to grow them in the ground to no better success. Fortunately, I am better at growing other crops and will stick to them in the future. I fo, however, have a question. Sweet potatoes are grown from rooted sprouts as opposed to planted eyes. Do they grow the same way?

    • bill says:

      Sweet potatoes don’t really grow in this climate, so I am not an expert on the subject. We’ve had a discussion about this in the Cultivariable Facebook group and it sounds like the same basic ideas apply. Sweet potatoes can have longer vines and more foliage area, but if you don’t let it spread out to catch sunlight or trellis it in some way, you won’t get the benefits.

  4. Earthdave says:

    I had been interested in the towers, to cope with limited garden space but also to avoid a lot of fruitless digging for that last potato. Some experiments on Youtube bear out what you say; they get a layer of spuds at the bottom, a lot of empty soil in the middle and then foliage out the top.
    As a modified container, this year I am going to try rolling a piece of linoleum into a ‘tower’ and plant in the middle of that (without needless vertical addition), just to make harvesting easier on my back. I’ll do a side-by-side comparison with traditional in-ground planting.
    By the way, I had also learned to do potatoes on the surface, under a thick layer of straw (what the French here call ‘paillage’) but the crop was terrible compared to my standard beds in the same soil and same weather. And I visited a nearby permaculture project with the same experience, so ‘innovation’ is not always helpful.

    • bill says:

      Straw can work, but it is very dependent on environment. Conditions can’t be too wet nor too dry and if you have rodents, they can become a big problem. My experiments with growing under straw have produced more voles than tubers.

  5. Kuen Woo PARK says:

    Biil and everybody !
    Thank you so much for good informations and experiences on potato tower.
    I like intorduce to students and hobby gardener.

  6. Jim says:

    I can attest to everything (first hand) you have explained and described in your article. I too fell into the “tater-tower trap” that is so pushed all over the internet. I had been using these 36″ tall towers for the last five years and generally speaking would only average fifteen pounds per container. The tubers only grew in one layer of soil as you described and adding soil would generally hinder the growth of vegetation. In addition, adding more tubers in subsequent layers of soil (filling the tower) rarely grew more potatoes by the time they were ready for harvest.This practice also required a lot of watering to reach the lowest level of tubers and a large amount of soil handling. Growing potatoes in the traditional method (in the ground) resulted, at least in my case, in higher yields that the towers did. My goal in using the towers is to grow more vertically due to my limited garden space.

    Thanks to reading and learning from your enlightening research, I have since cut my towers in half (now 18″ tall) and just planted my potatoes a few weeks ago…anxious to see the difference this year. What I feel is most beneficial, is the fact that you are willing to share your knowledge and expertise as you have with others! Thank you very much!!

    • Jim says:

      Reporting back regarding my previous post dated April 29, 2018…..
      My last entry stated that I had cut my 36″ towers in half (now 18″), due to the fact that the (Internet promoted) “tower” method did not work. So now I have doubled my containers from two to four, and considering the tubers only grew approx within ten inches of soil, in reality I had doubled my growing capacity. After a full (2018) summer growing season to now be able to make a comparison, I can say my yield not only doubled, but tripled when you consider the volume of unused soil I was filling these towers with. My containers are approx 48″ in diameter and each one had a yield of nearly 20-lbs. All four of these “half towers” were planted with assorted varieties of fingerling potatoes. I keep these containers up in my garden throughout the winter, augment the soil with organic matter, and they’re ready to go in the Spring. If I hadn’t found the Cultivariable site I’d probably still be trying to figure out what I was doing wrong!!!

      • Rio says:

        Thank you your two very detailed comments. My last veggie garden was back around 2000. I’ve been slowly searching online to brush up my knowledge to start a raised veggie garden next Spring. I was set to build a potato tower until finding this article.
        Your specific comments were very helpful. Congratulations on your higher potato yields. Cheers!

  7. Marc Meloche says:

    Hi Curzio, I experimented the potato tower two years ago, expecting a total failiure. Surprisingly it worked ! I did not obtain the 100 lbs promised but let’s say a fair 22.5 lbs from 5 small potato planted. What amazed me was that I got potatoes from bottom to top, at 44 inches from the ground !The biggest of them were situated near the surface and were even turning green due to sun exposure. Many tubers were attached directly on the stem, especially those near the top. The variety used was Kennebec. So, yes some varieties do produce tubers quite high on the stem if they are burried. You can see the results on my blog. The blog is written in french but you can look at the pictures.

    https://jardincooldotcom.files.wordpress.com/2016/10/tour-a-pommes-de-terre-recolte.png

    • bill says:

      Thanks for the Feedback Marc! (Although I am not Curzio. ;) )

      As noted in the article, you can grow perfectly good potatoes in a tower, you just can’t expect to grow more than you would in the ground if the soil were of the same quality. 22.5 pounds from 5 plants is 4.5 pounds per plant, which is a good yield, but one that is fairly easy to achieve in good garden soil with sufficient fertility.

  8. Alpha says:

    As a rookie, last summer I was excited with the idea of making a miracle harvest with a potatoes tower. I therefore went on and tried to build one. I ends up with 3 to 4 feets of filling. I dreamed all the time that my tower is filling up with potatoes. Just to be horribly desapointed. After I tipped over the tower, I had only long stems, a handle full of potatoes at the seed level. Nothing else, no miracle. I even noticed that the seed level was relatively dry, this as a result negatively impact my yield.
    I hope did my home work before trying, I but I learned the hard way, potatoes tower does work.
    I am however wondering whether planting seed at different levels of the tower would make sens.
    I wish I red this article before hand.

  9. lowtechinstitute says:

    Hi Bill,
    We’ve completed the research and guess what: the towers didn’t work in our controlled study! I’ve got a full write-up of the different methods here: https://lowtechinstitute.org/2018/12/04/potatoes-five-ways-a-trial-looking-at-different-potato-growing-methods/
    Feel free to use this any way you like as long as we’re cited. Perhaps our poster is useful: https://lowtechinstitute.files.wordpress.com/2019/02/moses-poster-scottjohnson.pdf

    I did some research into the towers over the year and I think I figured out a way that I could force them to work, but I have to test this out this year. First, as you probably know, potatoes form on “runners” that are put out during the third phase of growth (same time as the flowers). Therefore, any filling of a potato tower after flowering will never result in deeper layers of potatoes — the plants don’t produce tubers on stems after the flowers are seen. Therefore, if one uses a tower and really aggressively fills it up so the plant has, say, two feet of fill before it is allowed to grow tall and flower, perhaps — PERHAPS — the stem could produce tubers up that entire length. I’ll try this this year, but it seems like a really persnickety way to grow them.

    • nathanp says:

      This does not work either. What happens is that the plants exhaust themselves trying to climb out of a constantly increasing soil layer. They essentially have no energy left to product tubers, so it is actually counter productive to do this. I’ve tried it with several varieties, including some long season and intermediate types.

      Most commercial potatoes also do not set tubers on runners. They set tubers in a single location, and at a single depth (both of which vary by variety). They have been bred and selected to do this to make mechanical harvesting easier. That is the opposite of what many people who are trying towers want, making the vast majority of commercial potato varieties very poor for deep containers.

      You can grown them in containers, but limiting the height is the key to getting decent yields, and it should not be expected to get better yields than when grown in the ground, which is where potatoes have evolved and been selected to grow for thousands of years.

  10. Ellen Klaus says:

    I’m guessing you recommend containers that hold moisture but with good drainage? And that chicken wire would be too porous and prone to drying out quickly? Can you write about potato bags and what you recommend?

    • bill says:

      This depends largely on your climate, but I suspect that most people would find growing in wire cages difficult. I’m not an expert on growing in bags, but Curzio Caravati of the Kenosha Potato Project has done quite a bit of experimenting with this. You might want to check out the KPP on Facebook.

  11. Gendo says:

    Oh. I thought you were supposed to plant a new seed tater at every level, not that they were going to spontaneously generate new tubers just because you covered them in dirt. Never cared, never looked into these towers really. I grow only produce that’s actually expensive to buy, and you can get like 100 lbs of spuds for $10. Just not worth the time and effort unless you’re actually growing for sustenance innawoods somewhere.

  12. Pingback: The Poor Man's Potato Tower | Mind Your Dirt

  13. Bob says:

    I have tried towers with no luck, then had an idea. What would happen if I built a tower that was shaped like a ‘dunse cap’. I used wide spacing wire and built it up using straw as the wall and compost in the center and planted potato’s on the outside edge every 30 odd Cm all the way to the top. Potatoes poke out the side and I finished up with potato’s all the way from bottom to top.

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