How to set up a polytunnel

How to set up a polytunnel

John, Passionate gardener, Cambridge

Guide written by:

John, Passionate gardener, Cambridge

47 guides

A polytunnel is a valuable tool for any gardener. While polytunnels come in all shapes and sizes, they are all more or less installed in the same way. From choosing a spot to assembling the structure, fitting the cover and adding any finishing details, you will have to follow the same basic steps.

Important features

  • Preparing a spot
  • Checking the parts
  • Building the metal framework
  • Fitting the walls and doors
  • Fitting the cover over the structure
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Using a polytunnel to garden all year round


The temperature inside a polytunnel is considerably higher than that outdoors, which presents gardeners with a number of advantages. You can:


  • start growing earlier in the season;
  • produce crops that require warm conditions in regions where growing them outdoors would not be possible;
  • extend your growing season into the autumn when the cold starts to set in outdoors;
  • store cold-sensitive potted plants indoors over the winter;
  • and protect vegetable crops from certain diseases (mildew).

Required skills

Installing your polytunnel requires a certain amount of caution – at the risk of it blowing away in the first gust of wind! You will have to carefully read the installation manual provided with the kit and stick to the instructions and order of assembly. The rest of the tasks involved should be fairly straightforward for the average DIYer. You will have to take measurements, slot together parts (poles), use an electric screwdriver(if necessary) and use a spade to dig a trench.

Completion time

Around 1 day for small structures measuring less than 12 m2; 2 days for larger structures.

Number of people required

At least two people (to fit the cover).

Steps

  1. Finding a position and direction for your polytunnel
  2. Checking the parts
  3. Constructing the metal structure
  4. Fitting the wall and door covers
  5. Fitting the roof cover
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Spade

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1 . Deciding on a position and direction for your polytunnel


Polytunnels must be placed in sunny areas. Avoid placing your polytunnel too close to a tree or hedge, as the cover can get damaged by falling branches or gather dirt from falling leaves.

As far as possible, choose an area that is protected from the wind and direct your polytunnel so that one of the sides is facing the prevailing wind.

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Polytunnels

2 . Checking the parts


The parts that make up your polytunnel will be delivered in large cardboard boxes. Spread out all the parts on the ground and check that everything is there by comparing them to the list in the instructions:

  • covers;
  • poles;
  • feet;
  • clips;
  • cords;
  • etc.

3 . Constructing the metal structure


Start by assembling the framework by slotting all the metal parts together. Follow the instructions very carefully to avoid having to go backwards if you miss out a step or do something wrong.

Always start by assembling the horizontal part that will be fixed to the ground (if this applies to your model). Next, assemble the upper parts (hoops, brackets, etc.) by slotting or screwing them into place, depending on the model.

The metal frame is usually anchored down with stakes that are driven into the ground. These are usually ground anchor stakes that are 'screwed' into the soil using a tool that should be provided with your kit.

4. Fitting the wall and door covers


It's a good idea to choose a polytunnel with a door on each side rather than a single door – even if you go for a small model. This is because the wind that blows into the polytunnel needs to be able to flow out freely to avoid creating a 'parachute' effect.

5. Fitting the roof cover


For this step, you will appreciate the help of at least one other person in order to roll out the cover and tighten it over the poles.

It should be firmly attached to the base of the metal structure.

Sometimes, the polytunnel is actually held down by the cover itself. In this case, the excess cover found at the base of the structure is buried into a pre-dug trench and covered over with earth. As such, air cannot blow in underneath the cover.


Tip for assembling your polytunnel

It is important to finish fitting your covers on the same day because – as has happened countless times – a polytunnel with half its covers is liable to blow right into your neighbours' garden as soon as the wind picks up.

Fit the cover when it's warm outside or store it in a heated room in the wintertime: the plastic will become more flexible, which allows it to be fitted more easily.

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Guide written by:

John, Passionate gardener, Cambridge, 47 guides

John, Passionate gardener, Cambridge

When I was young, I was already working in the family garden. Perhaps that is where my interest in plants and gardening came from. So, it was logical for me to study both plant biology and agronomy.   At the request of various publishers I have, over twenty-five years, written many books on the subject of plants and mushrooms (a subject that is close to my heart).They were mostly identification guides at first, but shortly after they were about gardening, thus renewing the first passion of my childhood.   I have also regularly collaborated with several magazines specializing in the field of gardening or more generally in nature. There is no gardener without a garden, I have cultivated mine in a small corner of Cambridge for the last thirty years and this is where I put into practice the methods of cultivation that will I advise you in as well.

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