Polytunnels

Friday was a wet wet day, so mainly did some planting out in the greenhouse, giving all of the veg a thorough water . I also tweaked the signs for the trees and later helped Barry fit his woodstove flue in his van. Hopefully this will take the bitterness out of winter! It's been made for him out of a empty gas canister turned upside down. It then has a opening and door and a space at the back to attach the flue. This then leads out of the van. It's been named Bender as the opening makes it look like the face of Bender from Futurama...(maybe). 

Anyway, recently the weather has been pretty blustery, and a large section has ripped in the polytunnel. Saturday remained dry so we headed up with rags and special adhesive tape to see what we could do. The rip was horizontal and between two supports. WIth Barry outside high up on a ladder and myself on the inside, we did a pretty nifty job. First was drying off the edges with rag number one, (semi-damp) followed by rag two, (much dryer). We then cut strips to stick on, using a section of carpet to use as a support on which to press the tape down onto, (on the other side). We managed to reach practically to the middle, and then the outside was reached with the use of a "jabby stick" with some tape attached to that. We have some skills I tell you! Sometimes it really is about being inventive and resourceful with what you have to hand.

After we had that, we started noticing more and more rips and tears so we continued to patch bits up. The south-end doors were also showing some gaps above the frame, so we cut some old carpet strips and I practised refining my hammer and nail skills, (to be improved, sadly!)

Now, I'm still not sure if I like polytunnels. For one thing, I just don't like large amounts of plastic, and I have an already existing love for glass of any type. So greenhouses are initially a winner for me. However, I have done some reading and I have come to a conclusion:

I have no conclusion! Basically, polytunnels are good. Here's a summary that seems to cover it from Self Sufficient:

Basically speaking a polytunnel is constructed from a metal framed semi-circular tunnel covered in hard wearing polythene with UV inhibitors to maximise its lifetime. Over 90% of light is transmitted through the polythene, and the light is diffused which prevents plants from shading one another. An enormous quantity of air is enclosed by a polytunnel and so it stays warm much longer than a greenhouse and also does not suffer from wild fluctuations in temperature in the summer. Inside a polytunnel it is possible to recreate amediterranean climate and therefore grow exotic fruits and vegetables in your own garden. If bubble insulation is used (i.e. recycled bubble wrap), it is possible to ensure a frost free winter and an even longer growing season. The bubble wrap and be removed in the spring and then reused the following winter.

Advantages of Polytunnels

One of the major advantages of the polytunnel is cost. For the price of very small good quality greenhouse, it is possible to buy a polytunnel of four or five times the size and therefore cultivate many more crops. Polytunnels are not as permanent as greenhouses and therefore can quite easily be moved around the garden as required. It is for example much easier to move the polytunnel than it is to remove and replace the soil within a greenhouse: essential if you do not want disease to build up when you grow the same crop for a few years in the same place.

There are of course disadvantages of polytunnels over greenhouses. Firstly a greenhouse is much more attractive than a giant tube of polythene. Secondly, a polytunnel really needs to be located in a sheltered spot out of the wind or you risk losing it and all of your crops in the event of a strong storm. Thirdly, a polytunnel is much more difficult (or expensive) to ventilate than a greenhouse, and so the levels of humidity inside can promote the proliferation of fungal diseases amongst your crops. Finally, a polytunnel is vulnerable to playing children, excited cats, and stray lawnmowers/strimmers. Once you have torn the polythene of a polytunnel, no amount of taping and fixing will hold the damaged area together for long.

Here is an article from The Independent discussing in 2006 the polytunnel debate, and here is a link to The Soil Association's green paper of 2010, discussing protected  cropping, (in a polytunnel or greenhouse). Here is a link to First Tunnels list of pros and cons for small scale constructions, more appropriate for back garden-ers. This website was set up to 'defend' polytunnels and their use by farmers. (Sorry, there's a lot of links today!) 

Basically, to summarise all of the above: 

• There have been objections in the recent years as to the unsightly problem of large commercial polytunnels being constructed near residential areas
• They are cheap and (mostly) easy to construct, recyclable but also can be delicate to tears and strong winds, and also the plastic does eventually break down
• They extend growing seasons and you can produce a wider varieties of crops

I initially started this post to talk about polytunnels vs. greenhouses, but really, at a small scale there isn't much in it, bar cost. On a larger production scale, I'd recommend reading the Soil Association green paper as it is recent and relevant, (sorry I can't summarise it here but I literally don't have time right now!)

I think that if you had to choose, think about what you want to produce, how much energy will be used in maintaining it, how can it be reused or recycled afterwards, and think organic and long term. Other than that, it's really your choice: let me know what you think!