Keep fans running always. It helps exchange air and keep pests from resting on your plants. When the lights go out two major things happen. One is the stomata on your leaves close up In an attempt to conserve water in the plant. Another thing that happens is humidity spikes. When lights are on the emit heat which lowers humidity. Without the heat from lights it RH can soar so you may want a dehumidifier in there. Try to keep temp swings to a max of 10 degrees until the last couple weeks. A good dip into the high 40’s/low 50’s can pull out the anthocyanin if it is present, and give you some nice color. There is an argument to be made for the cold period increasing terps a bit too. Terpenes are a mostly a defense mechanism so stress can, in some cases, actually increase flavor.
