I’ve been thinking about a polytunnel for a while, and when one of the winter storms decided to pummel one of my greenhouses, picking it up and dumping it a few metres away, smashing all the glass and breaking the frame, I decided to replace it with a polytunnel. So how easy is it for a relative DIY dummy to put up?
Picture: RIP my old greenhouse, 25 years service
I’ve had a few of the cheap polytunnels over the years, the green ones that cost around £100 and are about 2mx3m, or “blowaways” as they are also known. Whilst they are very cheap and will last for 1-2 years they are not a long term solution. One issue with them is that unless you trench (bury the edge about 30cm/1ft deep) the covers will blow away in strong winds, pegs and lumps of paving slab simply do not do the job. However, the main issue is not that the cover blows away, it is that the support tubes are not up to the job. They rust quickly, often breaking off at the base and at joints. Even if you anchor the cover well, there is a risk in strong winds that the wind simply snaps the support frame and flattens the whole lot.
So cheap green polytunnels are ok for a season or two providing you don’t have too many storms or have a sheltered garden, but I wanted something that could last for many years.
To directly replace my 2m by 2.5m (roughly 6ft by 8ft) greenhouse would have cost in the region of £700. You can get them cheaper but I decided I wanted toughened glass rather than horticultural glass after spending a day picking fragments of shattered greenhouse out of my garden.
For roughly the same cost I worked out that I could get a 3m x 3m (10ft by 10ft) polytunnel, which handily fitted the space I had available. After a bit of research I went for one from Premier Polytunnels. The main reason for choosing them over their competitors was that their instructions were very clear, with a comprehensive video available on youtube for the exact polytunnel I was buying. The video made it clear that it was a two-person job, not to worry I thought, that’s what wives are for!
When ordering the polytunnel there are a lot of options, but I found that most of the manufacturers websites are very helpful, and guide you through the process. I went for a simple tunnel, doors each end, with a trenched cover fixing, this being the cheapest and simplest to install. Delivery was very quick, especially as just after a big storm I was expecting them to be very busy. The tunnel arrived with very clear instructions and with all parts clearly labelled. Tools needed were a drill, 13mm spanners, spade, stanley knife and screwdrivers.
I spent quite a while getting the foundation tubes correctly placed. They are buried about 12-18cm below ground with an anchor plate. This doesn’t seem very deep, but once they are in they are very hard to move. It is important that all the foundation tubes are upright, level, and the correct distance from each other. Working on my own this took a while, but it was possible. The frame then went up quickly, and was fairly easy. I found the middle hoop was slightly out of line, and nothing I could do would change it, but I was pretty certain that this would make much difference (it didn’t).
Picture: getting the foundation tubes correctly positioned took time.
Next up was making the doors, largely from supplied wooden battens. Again the instructions were good, and it felt like I was a proper woodworker, making a door from raw materials.
So, I’d got the frame up, doors hung and trench dug, all that was needed was to fit the cover. This was always going to be the hardest part, and the part I needed a second pair of hands, cue my reluctant helper. However, with a bit of swearing, sulking and apologies, the cover got fitted. It’s not the neatest of jobs, but it is tight, not ripped, and firmly in place. Only time will tell if it will stand up to the weather.
Picture: All completed. Not the neatest, but not too bad!
So all in all, it was about the same cost as a replacement greenhouse, albeit a bit bigger. It doesn’t require a base and can be put directly onto the soil and it took about 2 days to construct, mostly solo. The main issue I had was that my cordless drill was not up to the job. The kit uses self-tapping screws to fix the aluminum tubes, and my cheap cordless burnt out very quickly. I had a short delay whilst I finally splashed out on a proper drill, but hopefully this will last for years.
So, yes it is relatively easy to construct. If I can do it most people with limited DIY skills would be able to do it, it may not look perfect, but it should do the job.
It is now named “Pumpkin Palace” and will hopefully be home to my attempts at getting at least a placed finish at the Malvern Giant Vegetable Show for pumpkins and marrows.In the meantime it serves as a useful shelter for potatoes in containers, and early crops of carrots etc.
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