The self-watering polytunnel begins to take shape
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, Frances Gabe, 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. Follow this link to very silly film about the house.
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 pictures of the build on this photo gallery) 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.