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!


20 Responses

  1. Here, I would worry about voles etc with that much mulch so close to the tubers. I hill and hope for the best.
    Looking forward to your tower results!

  2. Rob, I am following this with keen interest, especially the part about whether pototoes will set in the straw.

  3. Also watching eagerly – I’ve never gotten potatoes to set into straw, but I’ve never packed it down with compost the way you do. This year, I planted them deep (12″ horse manure here, too…) and covered with “flakes” of straw bales when they emerged. Plants are about waist-high now and flowering…we’ll see…

  4. I’ll be sure to keep you all posted. With us potentially not “farming” at the market garden I am very keen on finding ways to produce a hundred+ pounds of spuds in one bed or less (100 sq ft)

    Emily, what variety were you using in the straw? Also, what were your theories on it not setting in the straw?

    Straw is very readily available here on the far edges of suburbia (I got the last 16 bales free!), but I am considering getting a shredder (maybe run it with the gasifier?) to break the stems up smaller to help in lots of things: weed suppression, ease of incorporation, and to reduce decomposition time.


  5. Thanks for the update, Rob. Looking forward to seeing your harvest tallies. My German Butterballs in buckets are looking good too.

  6. Too bad about the weeds.
    Are the weedy areas mulched?
    You may not have have much grass, but we mulch with grass clippings for weed suppression and it works great! The plants like the the extra nutrients as the grass breaks down, and it helps conserve moisture and keep the soil temperature more even.
    Maybe you could get clippings from neighbors (as long as they don’t poison their lawns with Scott’s or other chemicals)

    I’m looking forward to seeing the potato results.
    Happy gardening!

  7. I recently put the third layer of boards (made from standard household decorative shutters cut into halves) onto my spud towers and added more dirt to bury them for the last time. As noted above, they seem supernaturally vibrant and healthy — can’t wait to start harvesting some spuds! The shutters, in addition to being free, were a good choice because they offer lots of drainage so the towers don’t trap water.

  8. You bet Kate – and your gardens look great!

    Maitreya. Our main weed here is Quack Grass, similar to Couch grass. I have seen it run rhizomes vertically through 4′ of stacked straw – it simply laughs at mulch. The advantage in mulching is that it makes pulling said rhizomes easier. Another advantage is that other, mere mortal, “weeds” such as purslane, lambsquarter, amaranth, buttonweed, and thistle are a breeze by comparison.


  9. Hi Rob,
    I have three of these towers going – sowed 2.5 lbs of potato seed per tower: 2 Bintjes (which are late season) and one Salem (medium to late season). The trouble I have is keeping up with the hilling, and not so much with the work and timing of it but the amount of soil/compost that needs to go in! And then, where will I stash it all for next year?
    I’m a bit skeptical about straw, so I only use it as mulch and when the time comes to hill again I bury it in soil.
    Still, it’s exciting, and I can’t wait to see how many potatoes come out!

  10. Ah, I see.
    Yeah, we had torpedo grass in Louisiana, nothing would stop it. Pigs liked to eat it’s rhizomes though. We have something in WA called quack grass, but it isn’t as invasive as yours sounds.
    I just found your blog. Very cool. Keep up the good work!

  11. http://www.durgan.org/URL/?EIFPD 17 August 2009 Potato Test Box
    The seed potato is about six inches below the bottom of the box. The plant was carefully hilled often as the stalk grew. Hilling ceased when the flowers started to form. According to some there should be potatoes along stolens growing all along the stem. Experience has indicated that this is simply not the case. It will be a few weeks before the upper boards are removed and pictures supplied at each removal.

    http://www.durgan.org/URL/?ZELNG 21 August 2009 How a Potato Plant Grows
    Potato growing test box was opened today. The pictures literally speak for themselves. Clearly there is no advantage in carrying out excessive hilling when growing potatoes. The purpose of hlling is to insure the tubers are covered. For comparison one Pontiac Red was dug in the same row, which was almost identical to the test box potato in appearance.

  12. Durgan – thanks for the comments. I have had the exact experience with the majority of the varieties that I have grown when I have deep hilled in the field. Purple Vikings, however, have appeared to produce a second round of tubers. Time will tell – the tower of vikings is ill.

    The first tower – planted in April – is flowering for the 5th time. This is the one I am excited about . The concern is that this is also the one my dog dug up and mixed the seeds around so determining the variety may not be possible. I know what I planted in it (4 kinds) so if I get intriguing results I will replant towers with each variety to compare.

  13. Durgan, some other questions – did you only plant one seed per tower? The claims are often by “tower” rather than seed and I have seen as many as 15 seeds planted in some of the other trails. While the adventitious roots appear not to produce spuds, the extra 2-3′ of rich soil may provide enough water, nutrient uptake that a planting density that insane may be possible.

    I used about 1# (4-5 seeds) per tower to make the math easier. With all the blight and weird weather this year comparisons will be dicey.

    Great pics and thanks for your work!


  14. G’day
    My wife and I stumbled upon the idea of using straw a while back and as we rent our home, and there is no veggie patch in the yard, we grow all our veggies in pots. We had a limited success with growing potatoes in a plastic crate last season, and decided to try again this year with straw rather than soil. We hadn’t read this post, but figured that we could use plastic buckets with a single potato per bucket. We then cut the bottom out of a second bucket and secured it upside down on top of the first to create a ‘tower’ of sorts. So far these are working very well, in so far as the plants are now above the level of the second bucket. We’re now toying with the idea of adding a third bucket to allow for more vertical growth, as harvest time here in Australia would be late December early January and these plants are still growing vigourously. Any thoughts?

  15. […] farm gardens under control again, I spent a beautiful half hour this weekend working through the Straw Mulch Potatoes that I had put in as a test of deep mulched potatoes (no updates on the towers yet – 2 of the […]

    • I ‘m interested in doing the sheet mulch potatoes. On one of your posts you said you put down 12″ of raw horse manure and 3″ of straw in the fall. On another you said 3″ of horse manure and 12″ of straw as the plants grew. I just need to know how much manure was put down in the fall?

      • Sam,

        I must have transposed the numbers – 3-6″ of manure is the goal, with another 6-12″ of weed free mulch – usually straw, but leaves, woodchips, pine needles will work too.


  16. […] 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 […]

  17. This is really fascinating. I have just ordered several varieties of potatoes to try this year, mostly ‘novelty’ types, like All Blue. Your potato tower idea is really neat. Did you get a big harvest?
    I have been lucky enough to secure all the free hay, straw, compost and manure I can cart away for as long as I want, so I will be doing this.
    I never have used pesticides and this year , no artificial fertilizers, either. Should I let the horse manure ‘age’ before putting it in the bin?
    Thanks for the great ideas. Hopefully my cats won’t dig too much in them…they help me dig the rest of my garden. lol. Take care!

  18. Sayward,

    The towers did not work nearly as well as billed – I recommend deep mulching over a highly fertile bed. – check my post on deep mulched potatoes.

    If you do use manure in a bin it should be composted or aged at least a year to ensure a balanced soil ecosystem.


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