Polytunnel Re-design

In my last post I alluded to a change in the layout of my polytunnel. Well now that the tunnel is as clear as it will ever be, I sat down last night to plan.

When I first set up the polytunnel, I had a path down the middle and grew the crops on either side. This worked well, but the beds were too deep and it was difficult to tend the plants at the back, along the walls of the tunnel. As the season progressed, growth became luxuriant (to say the least) and air circulation was too limited.

One of the raised beds being used as an early season hotbed

In the second year, I built a raised bed on each side at the front of the tunnel, which worked quite well but there was wasted space down the back and the beds still became too deep to tend properly.

A central bed under construction

Last year I had the idea to put a narrow bed down the middle of the tunnel, where I grew my peppers. This worked very well. They were easy to reach.
I also put a 1000 litre water butt inside the polytunnel, both as a means to have plenty of rainwater to use and as a heat reservoir for the tunnel. But still the side beds were slightly too deep and I had to waste a lot of growing space to leave room to get to the crops near the side walls.

Polytunnel plan 2015

But then I read a chance comment on a website and it became obvious what to do. I can't believe I didn't see it in the first place.
The central bed should be the widest, as it can be reached from both sides. So I set to redesigning my polytunnel. It's not as straightforward as just changing the shape of the beds. There's a tricky crop rotation to plan for too. And it is tricky in a polytunnel, for most of the crops seem to come from the same family of plants! Tomatoes, peppers, chillis, aubergines and even early potatoes are all closely related. You can't keep growing them year after year in the same soil, as diseases can easily build up and nutrients become depleted. In the end, I came up with the idea of six beds for three groups of plants, to be rotated on a three year cycle. Since each group of plants has two beds, each species can change places when the three year rotation comes back on itself.
It may be easier if I show you the plan.
Where crops appear to be in the same place, they will follow each other. Some will be in and out early, others go in late on in summer, after the main crops have come out, to give winter crops.

The new polytunnel plan - 2016

2017

2018

So that's what it looks like on paper.
In reality, it's not quite so easy. There are paths to move, planks to resite and plenty of soil to be shifted.
I'll be getting on with I then.