OK, so the title of this post is slightly disingenuous. In truth it should be entitled 'how to find an old window and then ask your father to turn it into a cold frame', but that's a lot less snappy - and makes me sound a little pathetic, so I scrapped it.
As many of you will know, I have been whinging about needing a greenhouse for several months. As I began to realise this was not going to happen, I hatched a 'Plan B' - namely to create a cold frame. In many ways this is the best option anyway - it's cheap, takes up less space, but still manages to free up my kitchen windowsills and stop my dearly beloved making quips about Napalm as the cucumber plants start to infiltrate the tea caddy.
I found some old sash windows via an appeal on Freecycle. Two were rather rotten, so I'm keeping those in the loft for 'glass replacement emergencies' (I'm expecting a few) but a third was relatively OK although I treated it with Cuprinol as an added precaution.
The base was made from old 6" x 1" planks attached to 1.5"x1.5" posts to strengthen the corners. The boards at the sides were then angled to create a sloped top with the same adjustment made to the corner posts and front edge. This helps the space to capture the maximum amount of sun.
Of course, my father had to make a couple of 'improvements' to the design. Firstly, he added an extra 2" strip to the top of the frame. The window section was then hinged to this and means that when opened, the top can rest back against the neighbouring wall at a slight angle, making it less likely to fall down.
He also added a ventilation strip. A 2" section at the front of the structure can be lifted out which means you can let in air on a hot day, without having to prop up the whole window section. This is a lot safer with small children around. The other safety feature is a small catch on the side which means I can secure the top from inquisitive 'peerings in'.
The last safety device is of my own making. I have clustered a 'buffer zone' of pots around the cold frame to encourage the children to keep their distance unless I'm there to help them lift seed trays in and out.
Of course, if you want the design to be truly 'child friendly' you could remove the old putty and replace the glass with perspex, but for now I'm praying that my children will defy all expectations and refrain from breaking anything. I think that's the very definition of 'hope over experience'.