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Polytunnel Buyers Guide

Polytunnels are a common sight in gardens, small holdings and nurseries throughout the UK. They are versatile and are built to withstand the unpredictable British weather. Polytunnels have become a staple in both domestic and commercial settings- making them a go-to solution for many gardeners. Traditional greenhouses are been replaced in favour of the value for money, versatility and all year-round protection afforded by polytunnels. 

But what exactly is a polytunnel? We’ll explain this and much more in our polytunnel buyers guide. We’ll delve into the benefits of using them and why you should consider having one for your own plot.

What exactly is a polytunnel?

Although you may not know it, you will have seen a polytunnel before. Basically, it’s a steel frame with a polythene cover over the top to create a tunnel. Hence the name. The tunnels are traditionally curved but straight sided structures are also available. They are used by gardeners and commercial growers to provide all year-round protection for plants, crops and equipment.


Polytunnels act in a similar way to a traditional greenhouse. They trap sunlight and create a warmer, sheltered climate inside. This provides an excellent environment for growing plants that wouldn’t normally thrive in the unpredictable British weather.

Even though they are made from polythene, polytunnels are surprisingly durable and are designed to withstand even the harshest of weather conditions. Far cheaper than comparable sized greenhouses they are a more cost-effective and versatile solution for hobby gardeners and professional horticulturists alike.

What are polytunnels used for?

Unsurprisingly, they are mainly used for growing plants, fruits and vegetables all year round. This is due to the warmth and excellent growing conditions that you find inside a polytunnel. However, depending on the size of the polytunnel, you could also use one to keep machinery or equipment in. As polytunnels are designed to protect whatever is inside from the elements you needn’t worry about your expensive equipment getting rusty.

Polytunnels come in a variety of sizes, making them a popular choice with hobby gardeners and nursery owners alike. This makes them a great choice for people who want a flexible home for their plants. Direct Polytunnels has a huge selection of polytunnels that range from 10 x 12 feet – a great size for a standard garden or allotment plot, all the way up to 18 x 66 feet. The latter is used by many commercial growers throughout the UK and by ourselves on our own five-acre nursery.


The heavy duty polytunnels we’re discussing are not to be mistaken with the much smaller versions you see at your local garden centre or DIY shop. The ones we are talking about are specifically designed to last for years, rather than just one winter season.

Polytunnel Kits

We all love it when things come together… and this time we mean it literally. All polytunnels are provided as self-assembly kits. But they contain everything you need to build the structure.

Every kit will of course contain the main elements of your polytunnel. This includes the incredibly strong frame. When put together the frame provides the aerodynamics and strength required for it to remain stable in even the most exposed and windy sites. Of course, there will also be the polythene cover. This is where standards vary enormously between manufacturers. Don’t be caught out by cheap and very thin covers.


We use the Horticulture SunMaster diffused industrial polythene cover. It comes with a 5-year guarantee and has features such as anti-condensation, anti-fog, anti-drip, as well as temperature reducing properties for super-hot weather. All of which helps create the ideal growing environment inside the polytunnel. The quality of manufacturer also makes a massive difference to the covers lifecycle. A quality cover will last for at least five years. Cheap versions will only last a few months.

In your polytunnel kit, you’ll find steel corner diagonal storm bracing bars and steel roof bars in order to provide suitable strength for the structure. The kit will also include all the necessary fixings and clamps you’ll need that are made from high-quality steel (which is galvanised to BS EN ISO 1461 standards) to ensure extreme sturdiness and durability.

You will also find a helpful instruction manual to help you get started as well as email and phone support from one of our polytunnel experts should you need any help with your kit. There is also anti- hot spot tape and a roll polythene repair tape included in your tunnel kit. Just in case.

What are the best polytunnels?

As the same with a lot of purchases, you get what you pay for. This is certainly true when you shop for polytunnels. British made polytunnels are built to rigorous industry standards. Made from quality materials you know you’ll receive a great product. Buying a cheap imported polytunnel will not provide reliable protection for your plants. They are made from poor quality materials that will split, tear or fly away at the first sign of bad weather.

To get the best polytunnel for your money, you need to choose one that has guaranteed quality materials and components. That way, your polytunnel will last for many years, and you won’t be replacing it regularly. Which will obviously save you time and money in the long run.

Heavy duty polytunnels for home gardens

We all know how temperamental the British weather can be. That’s why it’s essential to choose a polytunnel which will be strong enough to withstand the unique climate and extreme weather we have in this country. But you can protect your plants, shrubs and ornamental trees from the ravages of the weather with a polytunnel.


And now the same heavy-duty structures used by commercial growers are available for home gardeners. With sizes starting at 10x12’ many of us have the necessary space. You don’t have to spend a fortune either. Cheaper than traditional greenhouses, polytunnels start at just a few hundred pounds.

Best polytunnels for small gardens

Not everyone is lucky enough to have a huge garden, but that doesn’t mean you can’t have your own polytunnel. If you’re limited for space take a look at a smaller sized polytunnel. 10x12’ for example. Of course, do take care to measure the space before ordering. One great advantage of having a polytunnel instead of a traditional greenhouse is that the ground doesn’t need to be perfectly level. They are also easier to put together. But even the smallest polytunnel will need two people to erect it.

Best polytunnel for an allotment or small holdings

If you’ve got a bit more space to play with you have more choice. You can look at wider tunnels with more depth, which of course hugely increases the room you have available for planting. A larger polytunnel will also provide you with more space to store the equipment you’ll most likely have on a small holding.


Commercial polytunnels

If you’re looking for polytunnels for commercial scale growing then, depending on your site, the bigger the better. No one size fits all. But with a range of tunnels available you will be able to fit different sized structures to maximise the planting potential of any site. Sizes of polytunnels go all the way up to 18x66 feet and everything in between. We use our own polytunnels on our 5-acre nursery. So, we put them to the test when it comes to commercial growing.

What about cheap polytunnels?

Of course, we all love a bargain. However, buying cheaper usually means that you’re not getting top quality. Buying a cheap, low-quality polytunnel is a false investment. It won’t last nearly as long as a higher quality product, and you could end up having to buy a new kit much sooner than planned. If you want a polytunnel that will last several years, its best to go with a quality product that is priced that bit more and manufactured in the UK. We produce all our polytunnels in our Norfolk workshops and all our staff are highly experienced craftsmen. But remember, British made polytunnels are significantly cheaper compared to a standard greenhouse of the same size, so you’re still saving money.

Should I choose a polytunnel or a greenhouse?

We mentioned earlier that greenhouses and polytunnels work in the same way in regards to providing a suitable climate for plants and crops. As mentioned above, traditional greenhouses are usually more expensive than a polytunnel of a similar size would be. This makes polytunnels, for the most part, much better value for money.

If you’re struggling for space at home a small greenhouse would probably be a better option. But, unlike polytunnels, greenhouses are very difficult to move once they’ve been placed on the ground.

You might think that polytunnels aren’t as durable or resistant as greenhouses. This isn’t the case with quality polytunnels. Their frames are designed to last for decades. Granted, you will need to replace the cover every five to ten years. But with a greenhouse you’ll also need to replace glass windows too. And the risk of accidents and injuries is far lower with a polythene covered polytunnel.


To erect a greenhouse, you’ll need a completely flat base to put it on. This can be an extremely time-consuming task as levelling ground can take a while and can be backbreaking work. Not to mention that actual greenhouses themselves aren’t an easy structure to put up. Especially with glass involved. Polytunnels are much easier to erect as they don’t need a level base and two people can put a polytunnel up in a reasonable amount of time. This is another reason why polytunnels are a much more practical option than greenhouses.

Walk in polytunnels

One of the advantages of having a polytunnel is the headroom. There’s no need to bend down when tending to your plants as there is ample space to walk through comfortably.


There are two different types of polytunnels: straight sided and curved. The main difference between straight and curved polytunnels is that straight sided models offer more head height and working room at the sides of the structure. So, the amount of headroom you need will affect the style of polytunnel you choose.

Heating your polytunnel

In the summer, a polytunnel is as effective, if not more so, than a greenhouse. In the colder winter months, you might want to prepare your tunnel by adding extra heating elements to keep your plants happy and healthy even when its cold outside. You could introduce either an electric fan heater or a traditional paraffin heater to help your plants through winter. You could also use bubble wrap or horticultural fleece to add an extra layer of protection against frost.

Erecting your polytunnel

As mentioned above, putting up your polytunnel is relatively straightforward and requires minimal preparation in comparison to traditional greenhouses. But please don’t try and erect the structure on your own. You’ll need at least one helper. And building your polytunnel will probably take a full day.

You may want to read through the instruction manual a few times before starting to build. That way you’ll be familiarised with the set up before you start. Depending on the size of your polytunnel, you might also want to have a step ladder so you can reach the taller/ ceiling poles much easier. You will also need a standard garden spade in order to dig a small trench around the tunnel in order to fix into the ground securely. But this can be easily done and doesn’t require too much effort. The setup is simple and requires minimal DIY knowledge. You can see more in the video below.

Covering your polytunnel

It’s best to use a good quality polythene cover or else it will not be durable enough and will split very quickly. We use great quality covers that are guaranteed for five years but are fully expected to last around eight years. If it so happens that your cover does get damaged, it can be easily replaced with a spare cover. Small tears can be temporarily repaired with tape. But a replacement cover should be sourced as soon as possible.


How long do polytunnels last for?

Again, this is where buying quality matters. Cheap polytunnels will not withstand the British weather for very long without breaking beyond repair. You’ll have to buy a new tunnel sooner than planned. Our polytunnel frames are built to last for 50 years and the covers will need replacing every 5-8 years. Our polytunnels have been tried and tested in the most weather-beaten areas in the UK and will last any gardener for many years after purchase.

What can I grow in a polytunnel?

We won’t go into much detail here. You can see our growing guides for more information on planting in your polytunnel. But, suffice to say, polytunnels offer excellent homes for many varieties of fruits, vegetables and even the pickiest of plant species. And does so all year round. A good quality polytunnel supplies the environment every gardener or commercial grower needs. Introducing a quality polytunnel to your garden or smallholding will help to encourage healthy plants all year round, increasing their lifespan and overall crop, making your gardening life much easier and more enjoyable. 

You may also be interested in:  Traditional Polytunnels    Replacement Covers    Commercial Polytunnels

*Photos on this page courtesy of Liz Zorab (Byther Farm)