I'm putting in circulation fans and can't decide on mounting them at the top, to blow down through the canopy or on the bottom, to blow up through branches and leaves. Input? Sent from my Nexus 4 using Grasscity Forum mobile app
I blow through my canopy right about soil height to keep moisture from settling under the leaves. High humidity leads to PM for my grow room.
I think air flow blowing up through the canopy is more efficient for the plants to breathe as they do this through their stomata which are under the leaves. Plus if the leaves are blown downwards they aren't efficiently positioned for collecting light. But in reality both ways work. Given the option I would have the fans below
CO2 is heavier than oxygen and will fall to the floor. I would say have one blowing up from the bottom to get the CO2 off the ground and another blowing across the canopy to keep it cooler and increase airflow around the buds. Sent from my Galaxy Nexus using Grasscity Forum mobile app
I agree with @[member="1milehigh"] both is best, you can't go wrong then. I have a ScrOG grow and the canopy is thick as shit. I have two 6" fans blowing through and along the top, and then two 4" fans blowing up through the canopy from below. Ideally I'd like to have a couple more 6" fans in there too