Warmer growing environment 

Step into any polytunnel and you’ll find that it’s barmy microclimate is noticably warmer than it is outside. The polythene traps heat, making it a great spot for growing crops that would usually struggle to produce reliable harvests in the UK. 

Extended growing season 

Soil protected by a polytunnel will be quick to warm up in spring, letting you sow seeds weeks earlier than would be possible outside. The higher temperatures reach right into autumn, increasing the amount of time slow maturing plants have to crop. 

Reliable conditions 

It’s well worth keeping an eye on your thermometer, but remember that wind, rain, hail and drought can damage plants just as much as a temperature drop. A polytunnel climate is entirely under your control - just be sure to choose a model with a strong frame, able to stand up to the weight of snow. The hoop diameter is specified with all polytunnels, and is relevant to the overall strength of the structure, the thicker the hoop the stronger it tends to be. Standard hoop diametre ranges from 25 - 32mm. Northern Polytunnels supplies the thickest of 32mm as standard. 

Much cheaper 

Any good polytunnel is far less expensive than a greenhoouse of the same size. This is either leaves you with more money in your pocket, or you may choose to get a bigger polytunnel or additional extras like irrigation systems and raised beds. 

Allotment sized options 

Tiny plot or garden? Never fear. Most manufacturers make garden polytunnels as compact as 8ft wide by 10 ft long and goes right up to 14ft wide by 60ft long. 

No planning permission 

Sheds and greenhouses don’t usually need permission from the local planning office and polytunnels generally fall into this category too. There are a few exceptions, for example if you live in a listed building or an area of outstanding natural beauty. If in doubt, contact your local planning office for more information. 

Save money 

Growing your own fruit and veg instead of buying them at the local supermarket has proven to reduce your shopping budget by at least £500 per year, with the added exercise you can cut your gym membership too.

Simple construction 

Most mid-sized polytunnels take a few days to construct (with 2-3 gardeners) and they usually come with detailed instructions. Northern Polytunnels Easy-Build Polytunnel takes half a day with 2 gardeners, it comes with comprehensive photo instructions and has the option of viewing a useful online video guide. 

Improved design 

Traditionally, the sides of the polythene cover were buried or trenched into the ground to hold them in place, which required quite a bit of digging. These days, base rail systems can be teamed up with foundation tubes to offer stability with little spade work. Want to ditch the spade entirely? Look for screw-in anchors - no mess, no fuss, no concrete. 

Can be moved 

Years of growing plants on the same spot could lead to a build up of pests and diseases. Crop rotation and good garden hygiene should be enough to keep your polytunnel soil problem-free, if not you can simply move it to another spot... or a different home entirely. 

Good for slopes 

Greenhouses struggle on land that isn’t prefectly flat. Polytunnels can cope on a slight slope with no expert help. Depending on your ground tubes and fixing systems you can raise the hoops slightly on one side to compensate for the gradient. Northern Polytunnels 

Easy-Build Polytunnel has a unique system that works well for this, as a bonus it will also add extra tension to your polytunnel to create a drum-skin tight finish. 

More standing space 

Traditionally, the hoops were semi-circular leaving little to no head room at the sides. Now, the hoops have been improved to have straight walls, meaning you have the freedom to move around easily without any bumps. This is also great for your climbing plants like tomatoes and peas, which can be suspended from crop/brace bars. 

Great ventilation. 

You may have chosen polythene instead of glass, but the Greenhouse Effect still applies. In the middle of summer plants can suffer in the heat. Vents can be added to your polytunnel to allow fresh air in, with netting on the inside it will keep unwanted intruders out. Fans can be added to circulate air, as hot and humid air can linger in the centre of larger polytunnels. 

Keep insects out (or in) 

As gardeners, we want to encourage pollinators into our growing environment and stop pests at the same time, which is why most good polytunnels with vents will come with netting. When you want to allow some beneficial wildlife in, simply open the doors.

Stands up to high winds 

If you have a breezy plot, you might be concerned about the stability of a polytunnel. Thankfully, most polytunnels can withstand over 60 mile per hour winds, with the option of adding brace bars to add extra support. Brace bars stretch across the inside of your hoops, and have the bonus feature of being a handy place to hang plants. 

Year-round harvest 

A polytunnel will offer some protection from light frost, allowing you to enjoy a selection of winter veggies, plus leafy crops at the coldest times of the year. Insulation, cloches and heaters will keep your plants extra snug even in the snow. 


Traditionally, polytunnels took days to construct and needed some on-site carpentry skills, as the only option available was to have timber base rails, door frames and doors. All needed to be measured, cut and secured into place with nails. Now with the Northern Polytunnels Easy-Build Polytunnel, pre-cut aluminium replaces timber, so it is easier and less time consuming to erect. 


Polytunnels aren’t just limited to a single gardening job. You can dry fresh garlic bulbs and herbs, install a potting bench and use the warmer climate to propagate seedlings before you move them outside in spring. Some people have even been known to use a larger polytunnel to cover an outdoor swimming pool or to dry laundry. 

Guaranteed long-lasting polythene covers 

Polytunnel covers will not need to be changed regularly, and have been known to last up to 15 years when kept in good shape. The lifespan of a polythene cover is determined by the quality, NOT the thickness. Most manufacturers will offer a guarantee with polythene (usually 5 years). Due to the nature of a polytunnel, algae can build up over time but this can be removed easily with some cleaning solution. Cleaning is best done in February and March before spring kicks in. We recommend Polytex Pro. 

Spoilt for choice 

Clear, diffused, SuperLux 50:50, white, green, bubblewrap, depending on your growing needs there are a range of different polythenes on the market. For general UK growing we would suggest Superlux 50:50 which is a nice middle ground polythene. 

Live in Scotland or the North of England where you may have more cloudy days than bright? Maybe a clear polythene would work best to allow the most of the precious sunlight into your tunnel. We recommend Lumisol Clear. 

Lucky enough to live in a location with alot of sunshine and with it high UV levels? Diffused polythene may work best to protect your plants from scorching, we recommend Lumisol Diffused. This is just a general guide, and will depend on what you’d like to to grow, but you get the general idea.