DIY Polytunnel - A Greenhouse Alternative

DIY Polytunnel Greenhouse

A reader sent me an email about a video called "How To Build A Polytunnel" (featured below) and suggested it might be worth mentioning - and I agree.

A Polytunnel Greenhouse is a much more affordable alternative to a traditional greenhouse and they can last 4 years or longer before the plastic needs replacing.

If you already had one a few months ago, you could be harvesting many of your own vegetables for Christmas dinner this year. If you put one together right now, even though we're near the middle of winter, you would still be able to plant your own crops of beans, coriander, figs,lettuce, and peas in December.

Can A Polytunnel Stand the Weather?

I'm more familiar with your traditional greenhouse using glass so my first thought was "how will a plastic one fare in a storm". After a bit of looking around the web I was surprised to learn that plastic or polytunnel greenhouses are surprisingly resistant to the elements.

This first video is a bit jittery (it looks like it was filmed on a smartphone) but it gets the point across - the owner filmed this the morning after a storm and it looks like it's completely free of damage. In the comments on YouTube the owner says it was holding up just fine with 1 foot of snow on top a little while later. You can see this person has put quite a bit of effort into making this sturdy with a lot of wood reinforcing and a small distance between each of the hoops which make up the frame.

The owner said he only spent $600 on this 10' x 16' setup - you can read more about it in the video comments.

It's one thing to say that your plastic greenhouse has stood up to strong conditions, so just to be sure I had a look for videos filmed during storms, and here's what I found:

Of course they won't survive the worst storm events, particularly if you have flying debris you'll end up with something like this next video, but you would probably get a lot of damage to a glass greenhouse as well if flying objects hit it in strong winds:

After reading up a bit and watching a few videos, I'm convinced that a polytunnel can withstand similar weather to a glass greenhouse - although it won't be quite as strong in high winds, they will perform slightly better in hail storms because the hail stones will bounce off the plastic like a trampoline.

DIY'ing Your Own Polytunnel Greenhouse

The guys over at Love2Learn Allotmenting put together this excellent video showing step by step how they built a complete polytunnel which they got from Premier Polytunnels.

They say it took them a total of 40 hours to complete the task, obviously a smaller one would take less time. Most of the work can be done by a single person, and you will probably only need a helper once it comes time to put the plastic on.

I really like the way they've shown every detail and every step that was taken. Although it should be possible to assemble your own kit just by watching their video, they've also given a complete set of written instructions here.

Although they say it was a 'permanent' structure, the plastic covering which is polythene (also called polyethylene) will degrade over time due to exposure to ultra violet light. Most manufactures provide a warranty for UV damage which can be up to 4 years long.

If you'd like to know more then there are some excellent books on the topic available from Amazon.com.

You might also like to read:
Gardening in Winter - A Few Tips for Small Scale Home Growers