If you are wondering about how to make your own coldframe, then you will be pleased to hear that it is actually very easy and all that will be required are some basic DIY skills and the ability to follow some simple steps with these now being listed below.
First you need to think of what the walls will be made out of and also what you will use for the transparent top as it must let as much light in as possible and this is why a lot of people will use old windows for this job, but you can use plastic sheets or build your own windows instead. The walls can be made out of bricks or wood nailed together as the main thing is it keeps the wind and rain out in order to give the plants some shelter, but if you are using wood do treat it so it does not rot.
What you then have to do is glue or nail the wood together to make a box or alternatively lay the bricks in much the same manner as you would do when building a wall. Clearly you need to prepare your foundation which means making sure it is level and if you want to put a liner inside, then do so after the walls have been built so you can remove it later if required since it is not built into the frame.
Once this has been done you can either just lay the window frames on top or some people will use hinges that are screwed into the top of the wooden frame and then attached to the window frames or whatever you are using for the top. It is also advisable to have some kind of supporting structure that can hold the tops open on warm days to let some air in much in the same way as you hold the hood of the car open when looking at the engine. Do consider using a metal pole since this will be stronger and will not break and attach this to where the middle of the window will be in order to support the weight.
So that is how to make your own coldframe and you can see that there really is nothing difficult about doing so and the entire job should not take you that long to complete. All that is left is for you to gather together the items you need and get started on building it and making it ready to move those plants into it when required.