[jacob and Georgina]

i have some left over perspex and thought in true smallholder style i could reuse it to make some cold frames to grow some lettuces, i have looked on the internet and this is something like i would manufacture  http://www.gabrielash.com/babygrand-coldframe.html however in this one only the lid is made of glass, will this allow adequate sunlight? or would it be advisable to make the front perspex as well? any help would be greatly appreciated!!   

[bloomer]

how thick is the perspex?

i have some coldframes with 6mm perspex lids a bit like the picture they work fine...

[ellisr]

Grandpa always had solid sides and a glass roof on his coldframes he said it kept the chill off the roots. I am going to build one jsut like grandpa's

[Fleecewife]

We had one like that but with more of a slope, so the front was lower.  It was made of wood around the sides and the floor, with old double glazing units as the top.  It was much bigger than the one shown, which is the advantage of making your own.  Eventually the glass broke under the weight of snow one severe winter and we have never replaced it.  The panes were not hinged, but located onto wooden pegs, so they could either be propped open or removed altogether.  Go for it

[NorthEssexsmallholding]

I made a couple myself a few months back, I used wood from pallets (free) and some perspex.  MIne were solid wood around the base with a perpex lid which I just weigh down with stones.  I've used them for my onions and leeks and they have been great.

Much cheaper than buying cold frames.

[jacob and Georgina]

thanks for all the comments, makes a lot of sense keeping the cold off the roots, after reading your replies i have decided to have a 6mm perspex lid with solid front and sides, but as fleecewife says i Will make it more of a slope and shorter at the front so the big perspex lid makes the most of all the sunlight!

A further question i would like to ask is how deep should the soil be, i will only be growing lettuce so was thinking about 6"?

[ellisr]

6" is sufficient for lettuce. I am planning a hot bed for melons next year with a deeper sides.

[jacob and Georgina]

thanks ellisr i think thats all i need to know for now anyway! should give me something to do for the next few evenings!

[Plantoid]

Having very recently heavily researched  the pros and cons for my green house I am happy to report  As such it is not direct sunlight you need in the greenhouse or cold frame it is day light ...unless it is winter when ther extra heat can be useful . That's why green houses are often white washed on the outside of the glass  the glass to keep direct sun light out and help keep the house cool.

Opaque  plastic  sheet or simple thick polythene sheets for a top opening is OK  paint the inside of the frame white to reflect the light around your plants .