So, I'm doing a small closet sized grow. I am able to keep my door open when the lights are on, so it gets proper ventilation. However, during dark times I have to keep the door closed. Is this bad? From my understanding, your plants need ventilation for heat exchange and CO2, but during dark periods I don't think that plants need either (since plants don't need CO2 during dark periods, and the lights will be off so not heat will build up.) Am I correct, thinking that I can keep the door closed during dark periods?
I think if you have an oscillating fan that moves the air around inside the closet during the dark period then you should be fine. I might be wrong but I remember something from Biology that plants do use CO2 during their night cycles. They have two different chemical processes that use CO2. Photosynthesis during the day and another at night.
Ventilation is crucial imo, i lost and entire crop to powder mold due to lack of ventilation at night. useing the fan to move air may help, but i dont think it will really change the humidity inside, so id say try and get some more if possible.
you might be thinking of the Crebs cycle for cellular respiration, which has a "light" and "dark" cycle portrayed in many bio textbooks. Contrary to popular belief, the dark cycle does not require darkness, and happens during and in conjunction with the "light cycle" some plants, with a type of metabolism called CAM save a part of the cycle for night (when it isn't so hot). these species include many cacti, pineapple, and iceplant. Cannabis, however, is not a CAM plant, as I understand. lack of ventilation during dark periods could definately bring on mold. I would guess that the plant still needs to transpire water at night. I think you're gonna need at least a little ventilation at night.