Potato Tower Results – An End to the Hype?

Thanks everyone for waiting all season for the results!  I finally got to harvest the towers about 2 weeks ago – the last of the vines had been killed on 10/10 when we had a very severe freeze of 23 degrees.  Considering we put the towers in the last week of April – this was a VERY long season for a 100 day potato like Carola.  I know that everyone is dying for the results so I will not keep you waiting any longer.  While I learned alot, the harvest was no where near 100 lbs per tower – I got about 3 lbs for the 1 lbs planted in the main tower

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Total Harvest for Tower #1 - about 3#'s

Now, way back in April I planted 4 different varieties into this tower, and the first month saw great growth as I expected from planting in such a rich compost medium.  However in comments on the Month 2 updates I reported that disaster had struck  almost exactly 60 days after the planting- heavy rains had waterlogged the tower, killing 3 of the 4 plants completely and severely wounding the 4th – which turned out to be a Carola.  That little plant had continued to grow, and I was amazed the fact that it flowered a remarkable 5 times over the course of the summer.  At each hilling the flowers would die back, the plant would send up new shoots, and then those would flower, only to have them die back again after the next hilling.  Here is what I discovered when I pulled the rungs of the tower off in early October:

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Spud set 18" above seed height (bottom level) - proof of the tower theory?

I even found a few more small potatoes above these. These potatoes were 18″ above seed potato depth – far higher in the soil than one would ever expect from conventionally grown potatoes whose potatoes are clustered within 6″ of the seed.  In fact the potatoes in the harvest basket above ALL came from this plant as it was the only one to survive the steep learning curve as I had to climb as I experimented with this new growing technique. Given that a Carola potato seed is about 3 oz. the 48 oz harvested equates to a respectable 16:1 yield.  Of note though is that spud size was small with only 3 of the potatoes being typical Carola size which is completely opposite what one would expect from the lavish attention these towers received: watering, weeding, compost growing medium, fish emulsion and compost tea foliar sprays – I babied this plant!

My strong suspicion, voiced as the towers grew, is that all the aggressive hilling perpetually knocks back the leaf growth and the plants never develop a lush canopy of sugar producing leaves to build the starch needed for a good harvest.  Perhaps this is an issue that can be worked around with better technique, but its a strong concern.

The other two towers were almost complete failures – the Purple Viking tower was knocked back with blight before tuber set, and  the Kennebec tower had its tubers rotting in the ground due to excessive moisture from my layered straw and a ground squirrel had eaten the rest.  Here is a very important picture from that tower which adds incontrovertible evidence to the theory that some cultivars will not root out from the buried stems at all:

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Buried "Stem" had ZERO roots developed after 3 months beneath the soil

The bucket is placed solely to provide enough contrast to see the root-free “stem”.  This is completely the opposite of what the Carola’s did – that plant had roots filling the entire tower and spuds at levels from 2″ above seed depth to 18″ above.  Given that there are 300+ potato cultivars worldwide there is certainly room to further the research on this technique should people wish to continue the task.

Want to grow your own experimental tower next year?

My Recommendations:

  • Plant one cultivar per tower – varied growth rates between varieties makes hilling difficult
  • Ensure VERY good drainage – I lost 80% of the plants due to waterlogging.  Spacing the rungs 3/8″ to allow for swelling is a good start, placing the tower on a light soil (or a mat of 4-6″ of straw) is also a must.  Pop a rung off near the bottom to check moisture before watering – these towers hold water VERY well.
  • Kennebec apparently will not root from the buried stems – hilling Kennebec is critical in field plantings though as they green up within hours of sunlight exposure
  • Tower height need not be more than 24″, though this may depend on cultivar choice – fingerlings get TALL.
  • Give canopy sq ft allot of thought – if you want 10#’s of potatoes you need to have enough leaf cover making all that sugar
  • Add straw in a mix, not as a layer.  My layers of straw blocked moisture and were saturated.  Straw is still valuable – worm casings present in the vermicompost I added hatched and I found dozens of very happy red wigglers in the tower nibbling on the straw bits and adding plenty of fresh castings to the Carola plant.

Do Potato Towers work?  Maybe…  that is the best I can say now.

My concerns:

  • Technique is apparently paramount with the tower systems with alot of pitfalls for the gardener – it is far from idiot proof — and with all the variables Climate Change is throwing at us we need a less finicky system.
  • Cultivar selection seems critical, and there is almost no research out there as to which kinds work.  Carolas and Purple Viking seem to be a good choice – Kennebecs are not.
  • Expense – $25 a tower for what seems to be only 10-20#’s of potatoes –if you can bring them to harvest– is a stretch
  • The Hype – promising 100#’s from 4 sq ft is a joke.  It still may be possible -and I hope it is– but it is not easy, it is not guaranteed, and it needs alot more research and realism before anyone goes filling the internet with wild claims.

One of the main Pillars of Intent of this blog is to provide real, proven, and pragmatic solutions for growing healthy food in small spaces such as a suburban backyard.  Do Potato Towers fit that bill?  No.  They are definitely in the experimental camp still.  I intend to plant the tower again next year with what I have learned to see if I can eck out a full tower of harvest – even 20#’s from 4 sq ft would be a huge accomplishment.

Here are some PROVEN techniques that will allow you to grow ALOT of calorie dense, nutritous heirloom potatoes in small spaces:

Buckets

Kate over at Living the Frugal Life tried some of her own experiments this year and I was very impressed with her results.  Using the ubiquitous 5 gallon bucket Kate was able to eck out between 8 and 14:1 yeilds which is as good or better than most organic field grown potatoes.  Buckets allow you all the benefits of container gardening – they work on balconies, the corners of porches or allow you to grow in areas with tainted soils.  Harvest is a breeze (dump the buckets!) and I love Kate’s idea of stacking the buckets in a pyramid.  10-12#’s from 4 sq ft should be possible with 6 buckets in a 2 teir pryamid.  Simple, easy, effective. Try it!

potato buckets

Kate's Potato Buckets (lifted from her blog)

Sheet Mulch Spuds

Have a bit more space?  I tried another experiment this year on a sheet mulched old strawberry patch.  My harvest blew me away: 30#’s from barely 1.5#’s of seeds in 8 plants of Purple Vikings – yes that 20:1!!  Blight knocked the plants back early, so tuber size was low – 50#’s would have been possible had they gone to full weight!  The bed was about 40 sq ft, so yeilds were not as high as the bucket per sq ft, but spacing could be tightened.  This method IS idiot proof – no additional fertilizer, the mulch is a natural Potato Bug repellent and all that straw keeps the moisture up really improving tuber size.

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These 8 plants = 30#'s of Spuds!

With winter around the bend it is a great time to try a sheet mulch bed for next year’s plantings.   Thanks for everyone’s contributions, thoughts, and comments in this expirement this year!!

Most of all, thanks for Being the Change!

-Rob

Potato Towers Month 4!

Yeah, you got that right.  Month FOUR.  Potatoes are supposed to be half dead, wretched looking things at much past 90 days, but tower #1 went  in Apil 27 and is still vibrant and strong.  The spuds I field planted at the same time have only wispy desiccated brown leaves left – some are already decomposed.  Here is Tower 1:

Tower #1 Month 4With almost 3′ of root zone, This tower could be very productive if the theory holds.  Flowering for the 4th or 5th time – the repeated deep hilling as levels are added to the tower is acting like a “reset button” for the life cycle of the plant: each time it will stop flowering, and put more energy into growth and converting the former stalk to root.  My one concern is when to let the top growth go – I figure it will take a syck amount of leaf area to produce enough sugars to grow 25-50#’s of potatoes.  The main reason the plants die back is that they are pulling all their sugar into the tubers and there is no where near enough leaf are to do that now – will the longer season have offset that?  This may be the last rung on this tower and I have hit it with Fish Emulsion to give it some boost.  Still very little pest or disease pressure – though the University Extension just sent out a Late Blight (of Potato Famine Fame) bulletin – it’s in Wisconsin and stiking terror into all us organic potato growers – it can wipe out a field in as little as a week.

Towers 2/3, which went in 2 months later, are doing fine with one variety – I believe its the Purple Viking- having about 6″ more growth (1 rung).

 

Only about 5 weeks in and over 20" of root zone.  These guys are vigorous!

Only about 5 weeks in and over 20" of root zone. These guys are vigorous!

 

Tower 2.  Great leaf coverage, but about 25% slower growth than tower 3 with only about 15" of root zone.

Tower 2. Great leaf coverage, but about 25% slower growth than tower 3 with only about 15" of root zone.

At the same time I put in Towers 2/3 I also planted a double row of Purple Viking in a Straw mulch.  Initial Results were very solid, but the limits of this system are becoming apparrent.

 

Purple Vikings with 6 weeks growth using straw for "hilling".  5 Gallon bucket for scale.

Purple Vikings with 6 weeks growth using straw for "hilling". 5 Gallon bucket for scale.

The issue I am having now is that the bed is getting freaky wide- the straw keep sloughing off to the sides as I try to add height. this is about the limit I think I can reach without adding an insane amount of straw to the outside of the bales- I have already lost 2/3’s the path on each side.  If yields are good, next year I can see “fencing” the bed with full bales to give it some structure, “hilling” with loose straw inside, and post harvest turning the whole thing into a giant sheet mulch or fungus bed.  Again, this could be a VERY productive way to de-lawn a hundred square feet of your lawn over 18 months.

On a final note, here is a shot of what the yeilds of the towers will be up against:

 

Current Record harvest for 1 Yukon Gold Plant: 3.5#'s!!

Current Record harvest for 1 Yukon Gold Plant: 3.5#'s!!

This is the best yield for one plant (3 sq ft) so far.  At this rate, a tower will beat field spuds in yield per sq. ft at bout 5#’s per tower.  Expecting the bar to go up as I harvest the higher yielding cultivars like Kennebec and Purple Viking.  Still, this was a GREAT yeild for one Yukon plant.  My challenge in the field is to figure out how to ge this much (about 2.25x normal) from each plant!

Weather remains crazy mild – we have yet to break 90 ?! — and extraordinarily dry.  My sunchokes and Cupplant are withered and dropping leaves – these are hardy native perennials.  Even the week with 1″ of rain only bought a brief reprieve – the soil is dry down several feet and will likely not recharge until winter.  That said, the humus rich soil at the market gardens are doing much better.  The yukon yield above is from an unirrigated plot.  Yet another reason I like to plant spuds early to take advantages of the June rains.  The Late Plantings will likely suffer significantly in tuber weight due to the low rain.  On the flip side – tomato flavor is UNREAL since the fruits are not nearly as watery.

  While the shoulder injury has been a pain, it has really forced me to SLOW DOWN which has had the benifit of increasing that most important farming / permaculture skill of observation.  If I am only harvesting at 50#’s an hour v. 100#’s I spend more time looking at pest damage, tracking soil moisture and tilth, and just plain thinking which is making me a better person.  A time to reap, and a time to sow…

Be the Change!!

-Rob

Potato Tower Month 3 + Straw Mulch Spuds

This summer has seen much of our backyard go to weed as first my overcommitment, and then my separated shoulder have reduced my time to the point where the Weeds are Winning.   I have chosen to see this as a further lens through which to view my gardening techniques.  If a garden bed or method fails miserably under these conditions, I need to assess the amount of input it is requiring.  The permaculture beds, while not thriving, are not completely gone either.  If I pull a thistle every time I pass by on my way to the raspberry patch they are manageable.  But the real treats are the two small scale potato experiments I am trying this year.

First, lets revisit our old friend: Potato Tower #1:

80 days in and 30" of root zone

80 days in and 30" of root zone

One of the plants survived the drowning of Late June.  The sides of the tower were placed too tightly together, and swelled shut as they absorbed soil moisture.  This turned the tower into a sopping mess as the excess water could not drain sufficiently due to our heavy clay soils.  3 Plants died, so I am down to this stalwart soul.  I have begun to space the rungs on two sides about 1.5″ to allow the soil to breathe.  There is 30″ of root zone on this tower, so yields have the potential to be fantastic.   Something very interesting occured over the past month – every time I added a rung and hilled the plants aggressively, the flowers would drop off, and then 1-2 weeks later new ones would form.  The sole remaining plant has now flowered 4 times.   As potato plants flower when they are setting tubers, I am optimistic on this as well.

Potato Tower #3 was planted June 20th – about 60 days after Tower #1.  This tower was planted to 100% Kennebec

 

30 days of growth and 10" of root zone

30 days of growth and 10" of root zone

This tower is about to have rung #3 added giving it about 15″ of root zone and is doing slightly better than #2 which is all Purple Viking.  This next rung will be spaced to allow some drainage, and I am also alternating layers of soil with straw to help prevent water logging.  So far so good.

When I was done planting Towers 2 & 3  I had 4 Purple Viking potatoes left, so I decided to try to plant a small bed using straw as the “hilling” medium.  

 

26" of plant below straw after 30 days!

26" of plant below straw after 30 days!

So far this bed has proven to be FANTASTIC!  Before we get all excited here, I must state that this bed was sheet mulched with 12″ of raw horse manure last fall, and left fallow until June Wk3 when I pulled aside the straw top mulch, dug two furrows and placed the Purple Vikings in the now mostly composted horse manure that was thick with soil critters.  I then covered the seed potatoes with a spade full of compost each, and covered them with 3″ of straw.   Since then I have added straw as needed, about every other day it seems.  The straw is *very* fluffy, so every week or so I am adding a spade full of compost to weight it down a bit and provide some nutrients.  So far the plot is 100% weed free and the potatoes are growing like crazy on top of the composted horse manure.

Learnings so far:

  • Straw Mulching is SUPER easy, but the jury is out on how they will set tubers in the straw
  • Towers can use more nutrients than I am giving them – the horse manure base on the sheet mulched bed is literally out growing the same variety in the tower 2:1 right now.
  • Towers of one variety each are *much* easier to hill

I had planned to be close to harvesting Tower #1 in the next several weeks @ 100 days, but the plant is still going strong.  With plenty of other spuds coming in from the Market Garden I will try to nurse the one remaining plant for as long as possible to maximize yields.  It seems that the repeated aggressive hilling is perhaps resetting “the clock” on the plant as the vines are still young and vigorous looking, with fresh flowers (typical at 45-60 days) despite the plants 80 days of growth.  Also, I want to expand upon the horse manure potato bed idea and find a way to limit the variables between mulch hilling and Towering to get a better side by side comparison of yields.  

But most importantly, the amount of toil going into these 4 potato “beds” is ridiculously low.  I am literally tending them with only one working arm and while the Towers may need to be edged, the growing areas still look great – I have not weeded any of them once as soil / straw is added faster than the weeds grow.   Even if I only get 15#’s per bed, this is 60#’s, or about 25,000 calories grown on less than 60 sq ft with no weeding and minimal watering -this would double the yield of my field spuds with 1/5th the work.  Exciting stuff!

-Rob

Potato Tower Month #2

So we are now 60% of the way to Potato Tower Harvest (average harvest date for spuds is 100 days) and things are progressing rather well.  With 60 days of growth in, I have added three more rungs, and the more vigorous plants are on rung 5.

Potato Tower Rung 4This really exemplifies the need, as “Walker” stated in the Month 1 comments, to place only one variety in each tower.  The vigorous variety (likely Yukon) would be on rung 6 if I had been able to push it with hilling.  The slower growing varieties are definitely struggling to keep up – actually  having their growth retarded somewhat due to the hilled soil washing over their top growth more than I would like (we’ve had some hum dinger rain events).  Still things are progressing nicely – other than some flea beetles they are disease and pest free right now.

Rung 4 TopThis is the tower after its latest hilling.  In a perfect world, the left plant would have received more hilling, and the right plant less.  The plant in the back is about right by my guess.  There are actually 5-6 plants that I have had to “train” into these three piles to facilitate hilling at 3 different levels in such a small space.

I just harvest my first (baby) spuds from my field sown plants.  They were Yukons and only producing across about 8″ of soil.  Even in this first attempt at Towering, I have potentially over 20″ of tuber production, perhaps doubling the yield or more when you factor in the TLC that such a small planting allow me to give it.  I have lavished water, the best compost, mycelium inoculation, and fish emulsion on this tower.  I can’t wait for Month 3.2 when I harvest!

As I have already gleaned many learnings from this, I wanted to put them into practice as early as possible so I have started 2 new towers – a Purple Viking and a Kennebec.  Main changes:

  • Single Variety per Tower
  • Hilling every 2 weeks leaving 3-4″ of Top Growth
  • Fencing to keep my crazy dog out.
  • Placing the towers where I want 12 cu feet of compost next year (edge of my permaculture guilds)

Even with the foibles of the First Attempt it is still going strong and I am very optimistic about the harvest.  Look for a recap towards the end of July!

-Rob

Potato Tower, Month 1

Last month I built my first potato tower, filled it with 6″ of compost, and planted it with a variety of spuds.  Now 4 weeks in, 2 of the plants are up and running, and the other 6 are finally breaking ground.

Tower FrontUnfortunately, due to my dog digging through the tower after I planted it, I cannot say for certain which plants are doing better, but I would guess its the earlies (Yukon and Kennebec).  I have done one small “hilling” when I added an inch of worm castings a week ago.  Yesterday I added about 3″ of soil to cover the two more vigorous plants and next weekend will add the next row of side boards and fill it with another rich soil mix (1:1:1 compost, soil, worm castings).  

Tower TopI am considering building an 8′ version of this to push the productivity of the backyard a bit – we do have some unused space along a fence line or two.I still have 150#’s of spuds to get in at the market farm (another 50#’s going in today) so seed is not a problem.  Even if I only net 15:1 pounds in harvest, it will be worth it to be able to condense the plantings to this degree.  The 8 pieces in this tower would have taken over 20 sq feet of space, so from a harvest per sq foot perspective I am already at a 500% improvement even if I only get 8 lbs of spuds, as I a only using 4 square feet in the tower.  For sub acre agriculture, where success is measured more in harvest per foot, this is huge.

All in all its a fun expirement for the summer!

-Rob

4 sq ft Potato Tower

PLEASE READ the final post in the series on Potato Towers.  Results were NOT 100# – not even close – I got less than 4# from 3 towers. This technique is not a magic way to produce massive yields which is why none of the articles ever show pictures of the harvest.  I grow organic potatoes professionally, and in addition to my field crops I try trails plantings each year.  If you are looking for a sure fire way to produce record harvests try the Sheet Mulch Method I document here.  That method yielded 30#’s from 10 plants – which is an insane harvest!

A huge focus of this blog is finding creative, sustainable ways to eck more produce from small spaces.  I also love growing calorie crops, especially potatoes, and furthermore I really enjoy building things.  So when a friend recently recommended the use of potato towers, I was very interested.  So yesterday I was off to buy materials for several compost bin orders I have and wouldn’t ya know?  2×6 pine was on sale.

spud-empty-top3The theory is simple – solancea plants will root from any stalk that has ground contact – I’ve seen both peppers and tomatoes rooting from their stalks.  The important part with potatoes is that they will lay tubers any where between the original “seed” potato and the soil surface.  Every time the potato plant gets about 6″ above ground, add  more soil – this is why you mound potatoes in the field.  These towers just take the mounding to crazy logical conclusions- the tower is essentially a 3′ “mound”.  What I like most about this kind of tower is the ability to “sneak” potatoes as the season progresses by removing a lower strip of 2×6 and grubbing around.  As most suburbanites don’t have root cellars (yet!) this is a huge plus if you are growing 100#’s of spuds.  Also, as the sides are opaque, spud production will occur right up to the sides, maximizing space and using less water compared to wire mesh designs.  Also, the lumber avoids some concerns that may be present with using old tires.  Old garbage cans, etc would also work.

The only major change I did for mine was that I used 2×4’s for the uprights as I had 10′ of them laying around the garage and I also put a sheet of cardboard under it to thwart the quack.  Speaking of which, this could be considered a hyper productive way to sheet mulch – cardboard out next years beds, and build potato towers along them – one could get (in theory) 600#’s of spuds form one 20′ bed (6 towers with 18″ spacing) and when the towers come down you have a raised bed about 2′ deep with compost when you’re done.  Hmmmm…

Planting the tower is easy, spud-tower-topI took 4 medium seed potatoes (1lb exactly) and cut them in half.  In the spirit of science, I used one each of Kennebec, Purple Viking, Carola, and Yukon Gold to see which liked this method more.  The growing medium I used for the first layer is 2 year old leaf mould, to which I added some pelletized chicken manure for nitrogen as it looked a little “carbon-ey”.  Weather here is mild and rainy, so they should be sprouting in no time.  The only down side is that right after the photo shoot, our new adolescent dog decided that this was a fantastic play pen and tore into it with abandon – I think I found all eight seeds, but she may have eaten one or two.

spud-tower-front1The claim is that the towers will produce 100#’s of spuds with about 1# planted in 4 sq ft.  That is freakish considering a record yield for field sown spuds is about 14:1; I was very pleased with my 8.5:1 last year.  In typical culture, 100#’s would take at least 75 sq ft, but more likely 150.  I am stoked to see this work and will certainly keep you posted.  Other great advantages – you do not need any heavy equipment to grow these – and harvesting is super easy.  Just be sure to save the soil somewhere for next year – mixing it with fall leaves and grass clippings in a compost bin would be a fantastic way to rejuvenate the soil.

Couple of post scripts. This thing is crazy overbuilt – I would feel comfortable parking a car on it if it had a cross tie across the top!  I think the prime driver of the dimensions is cost.  In the irony of modern economics, 2x6x8′ lumber is cheaper than 1x6x8′ lumber.  Also, pine rots quickly, so using 2x lumber will buy you a few extra years -though by yr 4 I expect these to be falling apart.  If it works I will likely build the next one using cedar decking for the sides and 2×2 cedar for the uprights.  That should last a decade, but would cost about double.  Another advantage would be that it would weigh half as much – this thing is heavy when built!

To make it more fun, we will likely be painting the sides with the kids – I have the idea of making each side a different person, and then we can mix and match the parts each year to create silly combinations.  I would also like to enlist my wife (waaaaay more talented artist) to paint a picture of a potato plant with a “soil view” of roots on one side.

All in all the total cost was about $30 (8 2x6x8, screws, and 12′ of 2×2) and about an hour of time in the workshop -mostly becuase my kids were running the screw guns and they are 5 and 7.  If you can truly get 100#’s of spuds that is crazy cheap – down to literally a few cents per pound over the lifetime of the tower.  Combine that with the ability for literally every single homeowner to grow all their potatoes for a year in as little as 8 sq ft this could be huge!

Be the Change.

-Rob

PS – As this post has been picked up by Stumble Upon and ranks high in most Google searches,  I would like to re-direct new readers to the conclusions of this experiment, and to also click the category “Potato Tower” for further reading.  Results with this system are proving very difficult despite the claims and I have yet to see the hype fulfilled in real life.

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