Potato Towers – Do They Really Produce High Yields?

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Robert Pavlis

Potato towers are a hot topic, probably because a lot of people have smaller backyards and they want to produce as much food as they can. The ads are very seductive: “grow 100 pounds of potatoes in a 4 x 4 ft tower.” And then there are the pictures of someone opening a small container and having dozens of large potatoes falling out. I never knew gardening was so easy.

There are two approaches to finding out if potato towers actually work. One is to look for actual studies that compare potato towers to other forms of growing potatoes, and the other is to try and understand how potatoes grow. After all, humans have been growing them for hundreds of years, so we do know something about them. I’ll take both approaches in this post.

Potato towers made from wood, built by craftthyme.com
Potato towers made from wood, built by craftthyme.com

What is a Potato Tower?

Potato plants are similar to tomatoes except that the edible portion, the tubers, grows underground. Traditionally, plants are grown for a few weeks, and then soil is hilled up around the plant. The tubers form in this hill, which is usually about six inches high.

Potato tower made from tires
Potato tower made from tires

It stands to reason that if a small hill produces a good crop, a bigger hill will produce a bigger crop.

How do you make a bigger hill? There are several ways to do this. You can place tires around the plant as it grows and form a vertical tower. Start with one tire and plant the seed potatoes. As they grow, remove leaves and place another tire around the stem. Four tires seems to be a popular height.

In the same way, you can use a wire mesh to form a cylinder. And then there is the deluxe solution where you build a square wooden structure as pictured above. Notice that the wood sides can be inserted, one above the other, as the plant gets taller. This design also makes harvesting easier.

All of these solutions are designed so that you place the starting seed tubers in the ground, and then as the plant grows, you keep adding soil to make the hill taller and taller. Add extra tires or pieces of wood to hold the soil around the plant.

At the end of the season, you have a large hill chocked full of potatoes—or at least that is the dream.

Do Potato Towers Work?

In order to answer this question, we have to define what we mean by ‘working.’ You will get potatoes with this system. But most people who go through the extra work of building towers want a higher yield than just doing it in the ground.

As far as I’m concerned, if potato towers do not give you a higher yield, they don’t work.

How Do Potatoes Grow?

This topic is well understood.

It all starts with seed potatoes, which could be small potatoes or larger ones that have been cut into smaller pieces. Each piece contains one or more eyes, the growing points on a potato. When the seed potatoes are covered with soil, they start making roots and shoots.

After a couple of weeks, rhizomes also start to grow. These are horizontal stems that grow for a while and then form the new potato at their ends. While this is going on, the main stem is growing taller and making lots of leaves. Through photosynthesis, the leaves are making sugars, which are sent down to the forming tubers.

The key to getting a lot of large tubers is to grow lots of leaves.

The description so far describes how early- and mid-season varieties grow. There is one set of rhizomes that forms very near the original seed potato.

We also have late-season varieties, which grow over a much longer season. These potatoes will make additional rhizomes higher on the stem, as high as one foot above the seed potato.

Potatoes are cool-season crops that like cool, moist conditions when tubers are forming. Optimal tuber set takes place with a night soil temperature of around 55°F (13°C). When nighttimesoil temperatures exceed 68°F (20°C), tuber growth is reduced, and it stops above 84°F (29°C).

The Height of Potato Towers

Most towers end up being three to four feet tall. The theory is that potatoes will be formed all along the stem, filling the full height of the tower. The problem is that most gardeners grow early- and mid-season potatoes, which only make new potatoes at ground level.

Just because you make tall towers does not mean that the plant starts making potatoes higher up the stem, and this is exactly what people are reporting when they dismantle their towers. All of the rhizomes and potatoes are at or near ground level.

Plant Science for Gardeners by Robert Pavlis

Leaves Equal Potatoes

Anyone who understands photosynthesis will see an obvious flaw in this system. In order to keep filling the tower with soil, you have to remove leaves from the plant. At the end of the season, you have a few leaves at the top of a very long stem that is devoid of leaves. The lack of leaves results in very little food being produced, which in turn results in few or small potatoes.

You can’t expect a lot of potatoes when you keep removing the leaves.

Too many Seed Potatoes

In normal planting, potatoes are spaced out along a row, and rows are reasonably far apart. Some tower recommendations place too many seed potatoes in the tower. Such crowded conditions don’t allow plants to grow to their full potential, and then they don’t produce a lot of potatoes.

Potatoes Are Cool Growers

Potato towers are just large containers that have all the soil above ground. That means their soil gets hotter and drier than the same soil in the ground. Potatoes produce the most tubers when grown cool and moist. If the soil in the tower gets too hot, they stop making tubers.

Potato Towers are a Flawed Idea

The premise behind this technique is that potatoes produce tubers all along the stem. If you grow a taller stem and surround it with soil, you will get a lot of potatoes. This is flawed thinking.

Early- and mid-season potatoes don’t do this at all—no matter how tall the tower is. Late-season potatoes do this a bit, but only in the one foot above the seed potato. A one-foot tower might help in this case, but there is no benefit to using a three- to four-foot tower.

What Does Science Say?

I can’t find a single scientific study that looked at potato towers.

Citizen Science Reports

If you go to YouTube, you will find many videos about potato towers. Quite a few are DIY videos that show you how to build and plant the towers, but almost none of these show you the results. Then there is another type of video, by real gardeners, that shows you the end result.

Admittedly, I did not find any that were very scientific, but some do have a control, usually comparing pots to towers. But if you take the aggregate of these videos, you quickly realize nobody is producing a lot of potatoes using towers.

Everyone is finding all of the potatoes at the bottom of the tower, which is exactly what science predicts. I selected one of these videos and took a clip from it because Dan Rogers took the time to have a close look at the vines. This image clearly shows that roots and rhizomes are only produced at the bottom of the vine (right side of the picture), and that is where the harvested potatoes were.

Potato roots from a potato tower showing no roots or rhizomes along the buried stems, photo by Dan Rogers
Potato roots from a potato tower showing no roots or rhizomes along the buried stems, photo by Dan Rogers

Do Indeterminate Potatoes Exist?

Lots of gardening sites talk about determinate and indeterminate potatoes, but most government sites and commercial sources for seed potatoes use the terms “early-season,” “mid-season,” and “late-season.”

If we define “indeterminate” in the same way as “indeterminate tomatoes,” where the plant keeps growing taller and making fruit along the whole stem, then I don’t think the use of the term “indeterminate” is appropriate for potatoes. Late-season varieties do make tubers slightly higher than the seed potato, but this does not continue along the whole stem.

It is possible that the real fruit of potatoes will form all along a tall stem that is exposed to light, as in indeterminate potatoes, but we don’t eat these fruits.

Growing Potatoes in Containers

Growing in containers might seem like the same technique, but it is significantly different. The container is simply used to provide good soil for growth. Leaves are not removed to create a tall hill, so the plant produces a good crop.

It is much easier to grow potatoes in the ground, but if you don’t have good soil, this is certainly a viable option.

References:

  1. Image of potato tower made from wood by Craftthyme: http://craftthyme.com/build-potato-boxes/
  2. Image of tire tower, by Tony Buser; https://www.flickr.com/photos/tbuser/2612148236
  3. Image of potato roots, by Dan Rogers, https://www.youtube.com/watch?v=EcCRYm4kCUs

 

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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

22 thoughts on “Potato Towers – Do They Really Produce High Yields?”

  1. Dear Robert, could you elaborate a little more about your paragraph on Growing Potatoes in Containers? I follow your ooints on towers and I have arrived at the same conclusion myself when researching on this topic. However, I’m curious about your thoughts on whether it’s work if containers (no more than a foot high) can be stacked asymmetrically on top of each other leaving spaces at lower levels for stem and leaves to grow out and over the sides of the stacked tower? I’d very much love to connect with you and talk more if you’re keen.

    Reply
  2. Thanks for the article. I’d kind of reached the same conclusion after trying potatoes for several years. The first two years, I tried a make-shift tower, with poor results. Year before last, got in a hurry and just tossed a few potato sets in my regular garden bed and got way better results. Last year, same thing. This explains what I’d already learned the hard way!

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  3. Thanks for another encouraging yet realistic article. I wanted to try my hand at potatoes this year. Your suggestions will have me doing the work where the plant needs it; not on my misled expectations. The only “manure” I need is what I put in my garden. Happy planting!

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  4. Dear Mr. Pavis: Your information is invaluable, and you have taught me so much. “Thank you” isn’t enough but will have to suffice for now!

    Reply
  5. In this circumstance being LAZY and not building towers has worked in my favor. I guess instinctively I new it wouldn’t work

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  6. Thanks for the very informative article. I haven’t planted a garden in some time and hadn’t considered potatoes when I did. At least now, I know what NOT to do should I change my mind!

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  7. I think that potato towers do not really work. in my opinion, the benefit of making such towers is not to stimulate production of tubers, but mainly to protect the tubers from the environment.

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  8. oops, I thought the idea of Potato towers was to plant seed Potatoes in gaps in the sides of the tower, so you have a maximum area of leaves – I’d never heard of these solid-wall towers you illustrate. I find that a tower requires lots of watering, because the leaves suck the tower dry pretty quickly, though this wouldn’t happen with a solid-wall tower. It makes more tubers for the area than planting in the ground, and you can reach in and get new Potatoes before the fall harvest, but it may encourage mice to eat the Potatoes before you get to them. I will try again this year, however, and I’ll weigh the production to get some numbers for you.

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    • …oops, a major drought this summer, and more-immediately-edible Lambsquarters took over the tower, so there are no results to report, except that the tower does take an awful lot of watering

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