DIY cold frames from salvaged materials

Cold frames

The Woodland Farm DIY cold frames were salvaged from local waste material. Here’s how we protect our seedlings from the Pembrokeshire frost:

1. Wood, and lots of it! All of the wood came from our local Alfa-Romeo car dealership in Haverfordwest. They were having a complete refit of the showroom, so we asked if we could take a stack of it, and they were happy for us to help them get rid of it….the manager said the wood came when their new outdoor sign was delivered. Enough wood to build four cold frames PLUS two Warre bee hives!

Cold frame double glazing glass

2. The large double glazing glass (on the large cold frame) came from a local double glazing window company.
All of the other double glazed units came from a lady who lives down the road, she was having new windows fitted.

Cold Frame Insulation

3. It’s a good idea to keep your cold frames from direct contact with the ground to prevent them rotting out. We used off-cuts of Polyfoam insulation, sourced from a building site (for a new Premier Inn, Haverfordwest).
Another benefit of using insulation underneath the cold frame is that it further protects the seedlings from risk of ground frost/ or ‘grass frost’ as the BBC like to call it nowadays.

Cold frame insulation for walls

4. The walls have also been insulated with silver-lined insulation. The one we found is called Recticel. This helps to protect from cold winter weather and also reflect/ bounce light around inside the cold frame. We found all the Recticel PIR insulation in a builders skip.

Cold frame thermal mass

5. The cold frames sit on bricks taken from old night storage heaters. Without getting too scientific (and boring) this is to give a ‘thermal mass’ inside the cold frame. Basically, the sun warms the bricks in the day time and that heat is slowly released at night time, thus evening out the average temperature….not too hot in the day, not too cold at night…. well, that’s the theory!

Sliding glass cold frame design

6. With the large cold frame we decided to slide the heavy glass panel across the frame instead of using a hinge design.

Water butt brick stand

7. Finally, we raised a couple of water butts near the cold frames on some red bricks. These also came from the Premier Inn building site. Job done!…. (until we make more frames).