How to insulate your Greenhouse

Posted in Category Greenhouse Equipment | by Jo | Comments (0)

How to Insulate your Greenhouse  -  

It’s a great idea to line the inside of your greenhouse during the winter – it makes economical sense, is quick and easy to install. Frost-proofing the greenhouse will also mean you can extend your growing season for up to 6 weeks.

Working out how much bubble insulation you need and just how to fit it can be a problem, so the chart below will give a rough guide to what you will need.

Size of Greenhouse (feet) Amount of Bubble Wrap Required

6 x 4 14m (2 rolls, 1.5m wide)

6 x 8 18m (2 rolls, 1.5m wide)

8 x 10 21m (3 rolls, 1.5m wide)

8 x 12 27m (3 rolls, 1.5m wide)

Don’t forget to allow 3 alliplugs  and allispacers  per glazing bar and likewise with the corner adaptors

When fitting the insulation, the following information may help. 

  • Measure from the floor to the apex of the greenhouse up one side and back down other, and cut the insulation to length.
  • Go to the back of the greenhouse, away from the door then fold the insulation in half and secure the middle to the top ridge.
  • Work along each glazing bar securing the insulation to the roof and sides with the alliplugs.
  • Have a sharp knife handy to cut the bubble wrap where the vents and windows are sited. Repeat for the next panel, gradually working towards the door.
  • The end panel which includes the door is best tackled by attaching the insulation to the outside of the structure, cutting to size and then securing inside.
  • Simply cut the insulation which covers the door as this will allow both access and the bubble wrap to hang down – it’s a good tip to allow extra bubble wrap below the door which you can fold and weigh down, allowing less cold air to enter.
Meet the Author: Jo Blackwell
Jo Blackwell

Jo Blackwell is our well-established Horticultural Advisor and the Kitchen Gardener in Stephanie's Victorian style Kitchen Garden. She caught the gardening bug when she bought her first home 21 years ago. Her first greenhouse soon followed and she later gained an allotment.

As well as tending the Harrod Horticultural Gardens, she enjoys maintaining her own vegetable plot at home. She has been a gardener for Harrod Horticultural for over 4 years now and has a wealth of experience in organic vegetable growing, ornamental gardening and in using all Harrod products.


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