Doors are never the easiest to grow in, but hey, If you are going to grow in "doors", you neeed to find good thick doors, timber is best, carve it out as deep as you can... dont fogot to add a drain hole ....
http://www.woodcarvingillustrated.com/
You can find the carving tools needed to carve the door...
One thing peeps always get caught is the actual door handle, just remove that and use it to put a small clone in.
Never put the Light to close to the Door, you will not only burn the plants you may also set fire to your growing door....
Good Luck...