I have my room in a closet and i keep the room around it about about 58 to 66, but when there in the light the temps are about 70 to 72 which i am very pleased with after the uphill battle i had when i switched from cfl to hid. Is 60 to 66 f to cold in the dark period?
Depends on the strains resilience. Some strains won't mind and other will struggle. Try to keep it in the 70s