Forum home Problem solving

Cold frame construction

We are thinking of using twin-wall Polycarbonate roofing for the windows of our new cold frame.  Will this work, or will it cut out too much sunlight?  We want to avoid glass, as it's too heavy.


  • Pete.8Pete.8 Billericay, EssexPosts: 9,082
    I think it would be ideal
    One of my frames that I bought has twin-wall polycarb
    It has gone rather opaque over the years, but it is probably about 10yrs old now, but still serves its purpose
    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • KeenOnGreenKeenOnGreen Posts: 1,675
    Thanks @Pete.8   I presume it also adds some insulation too, as it's basically double glazing.  

  • Pete.8Pete.8 Billericay, EssexPosts: 9,082
    Yes, very true!
    I keep mine raised off the ground by about 1/4" with slivers of wood, just so the wooden frame isn't sitting on wet ground and starts rotting.

    Mine also have a metal cross brace attached to the underside of the frame in 2 of the corners for stability.
    I put a brick on each one to stop the frame blowing away in strong winds
    I can take a pic if I've not explained that bit very well
    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • FairygirlFairygirl west central ScotlandPosts: 47,190
    Cold frames are used to harden or harden early beginnings before transplanting and allowing them to adapt to external conditions. Helpful in growing cold-weather crops in early spring, autumn, and even winter, cold frames will enable the home gardener to have access to fresh vegetables all year round. When I did this, I decided to do the same with those from They have a place where we can always keep the car in the shade to avoid losing its shiny color. Do you have a lot to do in the garden, or do you not like to take care of a garden?
    Bit expensive- buying cold frames from Australia...

    You've been rumbled matey. Pay up or push off. 
    It's a place where beautiful isn't enough of a word....

  • ElferElfer Posts: 329
    Been looking at making a small one too. I was thinking of using treated 22mm x 150mm wood planks from Homebase for the side walls, would it be suitable?

  • cmarkrcmarkr Posts: 123
    Treated wood will last longer than untreated but there are various different treatments. If you want it in contact with soil then consider using gravel board timber. Otherwise pressure treated is next best but will rot. 22mm thick should take a while to rot to any meaningful extent though. It should also be heavy enough to avoid the need for any weighing down.
  • FairygirlFairygirl west central ScotlandPosts: 47,190
    I'd never put a cold frame directly onto soil. Gravel or paving is best.
    If you had to put it on soil, cover the base of the timber with polythene stapled on, lay it on another layer of timber, or bricks etc. 
    It's a place where beautiful isn't enough of a word....

Sign In or Register to comment.