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

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:

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:

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!

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.

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