The self-watering polytunnel begins to take shape
Post categories: experimental gardening
| 15:31 UK time, Tuesday, 22 March 2011
Deep in rural Oregon, there is a house that cleans itself. It's aptly called the 'Self-cleaning house' and was invented by its owner, , who was born in 1915. She worked out pretty quickly that housework is dull, so she invented a bunch of labour saving devices for the house, including the ability to wash itself and then blow its interiors dry, even the paintings are waterproof. .
She's clearly a little unusual, but hey you shouldn't diss your own kind. By which I mean, I've just embarked on building a self-watering polytunnel. I'm not the first though.
The beginnings of the polytunnel with help from friends Geoff (l) and Joe (r)
The prototype lives in Scotland and was designed by Steve James. Steve adapted an ancient pre-Incan farming method of using deep-water channels between beds. These beds were raised up high enough so that the roots could breathe whilst still drawing up water when they needed it. The water also acted as a heat store (releasing daytime heat) to keep the beds from freezing over. This method apparently enabled farming in the incredibly harsh climate of Late Titicaca.
This all sounds like a plausible ancient technique, but how you then leap from there to a Scottish polytunnel is a feat of genius, but the man has.
Essentially the self-watering polytunnel has a pond underneath it, one that can have its levels regulated. Steve describes it as 'a large sunken bathtub with the sky tap left running'. The rain is collected off the polytunnel one end (the lowest point) and soaks sideways under the beds and if there's a little too much, then any overflow allows the excess to run out the other end.
I'm still at stage one creating the base. Thanks to the help of Joe and Geoff (of Berryfield days) I now have a pit with a deep channel in the middle, which acts as the water tank. This was then lined with some plastic I found in a skip and some stones and rubble Geoff dug up in the Cotswold (just to confuse the archeologist in the future). I have to play around with levels a bit more, find some more rubble, pipes and breeze blocks (to line the walkway over the tank).
If I'm honest it just looks a mess at the moment. But when I return to Steve's plans (Permaculture Magazine no. 66 pages 43-46 or you can see ) I can see logic, sense and some very healthy plants.
I am going to persevere even though part of me wants to run in the other direction.
Steve didn't water his polytunnel for a full year and only the garlic died. The list of things that thrived was much, much longer. He writes the point is not to make a tunnel that you never have to water (that was just an experiment) but to ease the burden of a workload. And if you can walk away on a hot weekend from this polytunnel then I am going to carry on the gamble of looking completely bonkers and keep digging.
Comment number 1.
At 22nd Mar 2011, physalis wrote:I'm glad there are people like Francis Gabe! Your self-watering polytunnel, an awful lot of work, but it makes perfect sense,good luck!
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Comment number 2.
At 23rd Mar 2011, Lia Leendertz wrote:Brilliant. I believe the other thing about them is that the water acts as a kind of thermal mass (is that the right term?) so it holds heat in winter and cool in summer. I've tried this in my greenhouse just by having a waterbutt full of water in it all winter but it isnt enough. Want to try this too one day.
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Comment number 3.
At 24th Mar 2011, alys fowler wrote:Hey Lia
I'm hoping I'll get a little more heat out of the water that way. At the moment I think I just need to find a lot more plastic as there are rather a lot of holes! That and breeze blocks so if anyone in Kings Heath reads this and has any spare. Please shout!
alys
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Comment number 4.
At 24th Mar 2011, hereisabee wrote:Since water warms and cools slowly, it must be pointed out that the proposed polytunnel is more suited to growing crops late in the season, than early in the year?
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Comment number 5.
At 25th Mar 2011, alys fowler wrote:It's not going to be any colder than a unheated polytunnel in the beginning of the year (and that in itself if better than no cover), though it might have some benefit as you suggest to the end. I think most probably that the depth of water is not going to be enough to make a huge difference either way. At this stage its still so experimental its all to be seen . . .
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Comment number 6.
At 12th Apr 2011, jauntycyclist wrote:good plan alys. take readings and publish a report/book.
there are lots of add ons one might try
e.g
using solar panel to run a mister etc
make friends with physicists and chemists.
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Comment number 7.
At 29th May 2011, christina77 wrote:This comment was removed because the moderators found it broke the house rules. Explain.
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