Fresh Air

Just a quick one..how often should i be opening the door to my growroom to let fresh air in? If anyone knows please let me know..i usually open the door about twice a day for around an hour or so each time

I honestly don't know, but i keep a humidifier which re-circulates oxygen and lets moisture into the air! It really actually helps haha.

Leave it open all the time. The more air the better.

yeah if you have the ability to do so, leave it open as often as possible, nothin wrong with some fresh air and sunlight.