tiny cold grow room

ok so im new to this and im just trying things out right now. Not to say i wont try my hardest but i have a small space i found about 6 feet long but 5inches wide. i put a fish tank (aqua grow)florescent tube at the top n im trying to fit 2 or 3 plants in there. the temp though dose not rise above 65degrees and sometimes gets down to 52degree with lights off. Im wondering what the coldest tempeture a marijuana plant can grow in is. And also will i b able to grow my plants stright up since they cant get very wide
Any help will b great im goin crazy with this room

I have had my plants at 50-65*F for a couple weeks when my thermo was busted..they survived but didnt like it... temps must be between 70-85*F humiditty. how tall is this room....... also one thing limiting horizontal space will cause hermies as far as i know.... 5 inches is useable but to me just seems pointless... check out micro growing ............. my only suggestion ..... or just build a real size grow box!!!!!!!
good luck

yeah thats a diffucult grow spot for sure