We’ve been receiving many questions lately about the benefits of polytunnels and how they differ from greenhouses. Today we hope to answer all your questions in this blog, as well as some considerations you should factor in if you go to purchase a polytunnel for your home.


What is a Polytunnel?

Polytunnels have been around since the 60s. They are constructed from a steel structure that is shaped in a semi-circle and then covered in polythene. This structure attracts sunlight, which heats up seedlings, plants, and the soil in which they grow to increase the rate of germination.


What are the benefits of a Polytunnel?

The main benefits of having a Polytunnel structure in your garden are that it can help your crop grow faster – approximately 6 weeks ahead of outdoor growing. Polytunnels are particularly popular in Ireland as they also protect the plants from our unpredictable weather system.


What is the difference between a Polytunnel and a Greenhouse?

This is one of the most common questions we receive. Essentially both structures operate in a similar way to promote plant growth, but there are some differences.


  • As there are doors at either end of a polytunnel, they promote a more controlled airflow in the structure than the greenhouse supply that comes in from vents and the one door at the front.
  • Greenhouses are more expensive structures to purchase, but they do last longer.
  • Greenhouses take longer to construct.
  • Polytunnels tend to need to be replaced periodically.
  • Polytunnels are easily moved, whereas a greenhouse will take time to alter.
  • Polytunnels can be built on bumpy ground, whereas a greenhouse must be constructed on flat ground.
  • Greenhouses usually require additional heat during the winter months.


What do I need to consider before buying a Polytunnel?

  • Depending on where you are building the polytunnel, you need to ensure that you have planning permission.
  • The most common size of polytunnel is 2 to 5 metres in width by 2 to 20 metres in length – allotment-garden.org.
  • Check out the overall quality of the structure before purchasing. Ask what the ultraviolet resistance and lifespan of the sheets is. Charles Dowding suggests using the standard light-diffusing polythene, which admits around 89% of daylight.
  • Is it easy to construct yourself, or will you need someone to come and do it for you?
  • Positioning your polytunnel is so essential. It needs to have full access to the sun with a proper shelter to ensure that it doesn’t get too much exposure to bad weather. According to charlesdowding.co.uk, “North to south is ideal.”
  • Another top tip is to bury the polythene in the ground at a spade’s depth to protect the tunnel from pests, weeds, drought and cold air around the plants.
  • Lastly, make sure your structure comes with foundation tubes to hammer into the ground at about 12-18 inches to strengthen the tunnel structure.
  • We hope this blog has helped you better understand polytunnels, and don’t forget that we have what you need when you need to pick up some soil.