Help, How long can plants be with out light 5 weeks to go.

My fricking lighting system is messed up ballast is running no lights. I am on 10/14 so I went to check soil levels and to my surprise no light. I unplugged them from timer and plug into wall socket the ballast started running and fans but no light, I can not do anything until tomorrow at least, what do I do??? I tried searching and not finding info.

I should also mention they are in a basement and it is getting cold 40's should I put a heater in room since it has not light to keep temps up, I am so stressed last time I checked them they were so pretty and had tons of crystals forming on buds. Hairs are just starting to change. Ugghh this is not easy.