Hi Anna M. I to am Anna M .I think you would close it in with pexi glass.

Hi Anna

ANOTHER GOOD WAY IS HEAVY DUTY PLASTIC. DEPENDS TOO WHERE YOU LIVE. iF IT SNOWS AND GETS BELOW ZERO, i WOULD CONTACT A BOTANIST ON LINE OR IN YOUR AREA.

go to lowes,they have hard plastic sheets that are rippled , i have the light blue in my cactus room, that we made on sides an for roof,they also have foam wedgie like things to go with the plastic, so it will make it more closed off ,this works perfect.. good luck it will be fun for u, an not that expensive IT WILL WORK for u, it may be hot in the room for summer,just take off panel or make a window for the heat to escape

I guess you will need to keep the kitties out.
Use a basic framework of 2 by 2 strips of wood to make a rectangular frame around a flat area large enough for your plants. Leave a little room for space between the plants as well as along the place where the plants come up to the frame. Make a matching rectangular fram for the lid. Then construct 4 longer 2 by 2 segments to make the 4 corners of the green house.
Once you have the frame screwed in place with wood screws, and it can stand ok on it’s own. Cover the two largest sides of the rectangular cube with chicken wire as well as the top and base.
Cut the wire so the lid can come off, and add wire to the smaller sides. Cover this chicken wire with heavy mill plastic and you have a nice little green house which should keep the cats out.

You could place plastic over the screens in hopes to prevent cold air coming in. You also could place a electric heater and place the temperature Gage to make sure that you keep your plants above 40ish. Next problem would be lighting? You might have to do some research on the proper light to keep your plants happy. Hmm….. maybe grow lights?