A polytunnel is, quite simply, a bigger version of a cloche. Whereas a cloche is normally used to protect a small number of plants or an individual plant, a polytunnel covers a much larger area of your garden. In construction terms is a row of hoops with a plastic cover and acts as a cheap greenhouse.
Polytunnels exist in various sizes. They can be tall enough to walk through if you grow tomatoes or cucumbers. If you grow smaller plants and vegetables, such as lettuces or strawberries, there are models which lie much closer to the ground. The length and width depends on your needs and the size of your garden.
Make or Buy Your Polytunnel?
After you have chosen the size of your polytunnel, you have to decide whether to buy one or make one.
A large polytunnel will cost around the same amount as a small greenhouse. Making your own is a good alternative. There are two main materials needed to make your own polytunnel – the metal tunnel framework and the polythene cover.
The framework can be sourced from building sites, scrap metal merchants or even scaffolding firms. These places often have leftover bits of metal tubing or pipes and will cut you a few bent or damaged pieces if you ask nicely. They are usually glad to get rid of it so it wouldn’t cost you anything. The plastic cover is the most costly part to buy and the cost of course depends on the size of the tunnel you are erecting.
Large or Small Polytunnel Build?
If you are building a tunnel large enough to walk through, you will need additional materials such as timber to make a frame and a door. You also need to fix the cover to the metal frame using battens. Old floorboards, if you can find them are handy for the perimeter of the tunnel. To fix everything together, don’t forget the wood screws.
It is easier to build your own small polytunnel, rather than the larger ones. There is no need for a door and the framework doesn’t have to be as sturdy. If you are good at DIY and have a few contacts, you shouldn’t have too many problems building a walk through polytunnel, but bear in mind that a small one is much simpler.
Buying Polytunnel Kits
You can buy complete polytunnel kits, which include the door and frame from around £300. The prices vary according to size and supplier. The advantage of a ready made kit, however, is that you can put it up straight away.
You don’t have to source materials or wonder if you have the correct components. You can choose a polytunnel with ventilation and ask advice about the best type for you. Bear in mind that you will still have to erect the tunnel and it’s a much easier job with two!
Living With a Polytunnel
Place your tunnel in a part of the garden protected from wind and in maximum sunlight. If possible, shelter your polytunnel when the sun is at its highest, either by putting it near a tree or by artificial means.
Whether you have made or bought your polytunnel it is a good idea to clean it once a year and repair any holes as soon as they appear. This will make the cover last longer as they do not last forever and you may find you have to change your cover every five years or so.
The Planning Problem
Planning permission for polytunnels is a thorny subject. Many councils are insisting on it. Bigger polytunnels are not seen as temporary buildings and some communities see them as a blot on the landscape. There is no national law and each case is studied individually. It is wise to check what is allowed in your particular area before you go to the time and trouble of making or buying your polytunnel.
Polytunnels are a good alternative to the greenhouse. You can make your own at the fraction of the cost, provided you have the know-how. Even if you buy one, a large polytunnel will cover more area than a small greenhouse for the same price.