What size Polytunnel do I need?

So you have decided that you want a polytunnel and are now wondering what to do next? Well this is a guide to choosing the right polytunnel for you and your family. Before you make your purchase, you should take some time to judge what size of tunnel you might need. In doing this you can make sure you don’t end up buying too big or worse again too small. heres some pointers to help you.

 Family size

  If you are planning on growing your own food you may want to consider how many mouths you have to feed and plan accordingly. For family of 4 we would recommend 15x26ft polytunnel is a nice size to grow good evenly spaced crops. This of course links with the following point.

Choice of crop

You should think about the type of crops you would like to grow in your polytunnel and how much space they might take up. For example, if you were planning on growing grape vines or peach trees you would need a longer tunnel. you may even consider a short 21ft wide tunnel to allow more space for other crops to grow.

Ability to store

Another option when growing your own food is to freeze some of your harvest. This will allow you to have a constant supply all year round without having to grow constantly. If so you need to take account of the capacity of your freezer units to decide how much crops you will need.  You may have to purchase a larger tunnel so you will have enough food left over after the season ends.

Time and budget

A very important thing that people forget about is the amount of time they have to put into their polytunnel. Growing your own food is not incredibly hard work and can be very rewarding but it does involve work nonetheless. You should think about how many hours a week you can put into a polytunnel and match the size accordingly. If you’re working full time and have young kids too, you may have to go smaller than you would otherwise. You may also want to check your budget and see which size best fits you


Buying a tunnel is a great investment to make and yields many rewards although you only want to do it once. It’s important to do it right so you have to make sure you’re getting something that will last a lifetime. There are 3 main parts to any polytunnel, the structure in the form of hoops and bracing, the door frames which are usually timber and the polythene cover.

It’s is a common mistake for people to assume that the life of the polythene defines the polytunnel. It is very important to get a good quality polythene but it can be replaced, a failed steel structure will be more costly. For the structure, you want to make sure you have the right tubular material with a good wall thickness. We advise gun barrel steel which is one of the best materials for the job. It has proved to withstand some of the worst weather that Ireland has seen in years.

For your door frames, you should make sure that the timber is treated to get the longest life possible. If not it won’t be long until your looking to replace it.


As for the polythene, it’s is worth your while to get the best you can which tends to be 800 gauge. The official life span of this is 5 years. If you do a perfect job when covering the tunnel and get it very tight, the life span can be doubled. We have had reports of polythene 13 years old and still going. It is very important to note that lower quality plastic covered well is better than a high-quality plastic covered poorly.

Now that you have come to the end of the list you should have all the knowledge you need. Hopefully when picking out the perfect polytunnel you know what you should look for in a kit so that you get the best value for your money.

Happy planting

D-Plant polytunnels are the heaviest on the market, click here to see the full range of sizes.