Can I have a Polytunnel in a Wind bound Area?
The answer to that Question is yes, you can although there is a few things you have to take into consideration before you purchase a polytunnel.
Before you buy your tunnel, you want to find the best place to put it. A sheltered area would be the best case but if that’s not a possibility its nothing to worry about.
Quality of structure
A common misconception in the purchase of polytunnels is that the plastic is the most important. Although replacing the structure is far more expensive and usually means the plastic is ruined too. The first thing you should be asking about is the steel. The pipes should have a substantial size wall thickness to withstand storms as well as being an appropriate diameter for the size of the tunnel. At a minimum, the steel should be galvanised to be resistant to corrosion. If the structure meets these requirements then that is one less thing to worry about.
The shape of your tunnel could have a large effect on how well it can withstand a storm. One of the main things to keep in mind is that strength is in the curve. In recent years, it has become more popular for people to buy straight sided tunnels. This feature inhibits the structural integrity of the tunnel and allows it to bend in the wind. A tunnel with very low straight sides and a large curve can offer the most strength. This will allow you to work right into the sides without bending over. Another weak point in a polytunnel can be the top where the two half sections of the hoop meets. If this area is relatively flat it may be a problem when your tunnel is put under pressure by wind and snow.
When it comes to bracing if you have everything else right, corner bracings and a ridge pipe will be adequate for internal support and perhaps crops bars for added support. As regards to the size, we recommend a 15ft wide for you garden or a 21ft wide for commercial purposes. These sizes have the best width to height ratio giving you the best stability in a storm. Its also best to have the side of your polytunnel with the least amount of surface area facing to the prevailing winds.
The foundations in a wind area is the make or break of your Polytunnel. First of all you should set everything in concrete, both your foundation tubes and your door frames. This gives you a good strong anchor fixing the Polytunnel to the ground. If possible it’s a good idea to use a trench to fix your plastic down. This gives you extra stability ensuring your polytunnel won’t go anywhere. However if you need to use a base rail it is important to fix the brackets to the pipe using tek screws.
Although the plastic is not the most expensive part it is still a very important factor. Essentially it’s what makes a polytunnel a polytunnel. Now a days most polythene is of reasonable quality but the trick is to get it tight. Good polythene will break as it flaps in the wind the same as bad polythene will. You will only get value for your money if its tight and not able to move, to get the tightest possible cover its best to apply it on a hot day. The heat causes the plastic to become softer, as the weather cools the plastic shrinks giving you the best finish.
Maintaining and final touches
Like anything the best way to get the longest life and the most out of your polytunnel is regular maintenance. This involves spot checks for tears and holes that may have been inflicted on your plastic. In a windy area, it’s very important to mend these as quickly as possible with repair tape. This will avoid the tears getting bigger. Its also a good idea to have strong doors on your tunnel. Make sure you have good quality hinges and locking bolts to keep it closed during a storm.
Once you have all of the above in line you can be sure to have no problems with any storms interfering in your year-round gardening.