How to keep my grow kit in a dark spot and a spot at 25 degrees Celsius at the same time!

I have 4 small closed plastic containers with breed for magic mushrooms. Now as i mentioned in the title: how do i keep this 25c°? For now ive put them in a box that i painted black on top (to absorb heat from sunlight) and closed it so it's dark. But is this enough? And what should i do at night. I took the heating component out of a hot glue gun hoping i was able to make something out of it like a heater. I still have it. Any advice or ideas? via /r/shrooms http://ift.tt/2smFSy9