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

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

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!

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