thirst4knwledge
Member
A grower on the Green House Seeds forum (dominicangreen) has a killer grow room and describes how he vents every three hours during lights-on and continuously at night. Also, while I realize his advice and books are somewhat questionable, Jorge Cervantes states in his latest book on page 322 that "Carbon dioxide-enriched plants still need ventilation to remove stale, humid air and promote plant health" and on page 326 "The room must also have a vent fan with flaps or a baffle. The vent fan will remove the stale air that will be replaced with CO2-enriched air." However, if there is absolutely no need to ventilate during lights-on other than for cooling, that information would certainly be helpful because it greatly simplifies enrichment timing. I am in the process of converting my 7'x8'x10' grow room to include CO2 with a Sentinel controller and I want to do it correctly.
Besides for emergency (high temps) and lights off ventilation while you're not enriching the air (up to you but isn't a true sealed environment), it is unnecessary to ventilate the room. I do agree with what Jorge Cervantes says about removing "stale, humid air", but the air in my room cannot be described by either of those words. I have multiple fans that serve multiple purposes (circulation, reducing risk of mold, promoting strong plant structure), so my air isn't stale by any means. Also, I use a dehumidifier, so my rh never leaves the optimal range. Last, I have an air conditioner so temps stay right around 85*f. If I didn't do those things, then I would definitely be ventilating my room, as I'd rather lose CO2 than lose my plants because of ridiculous temps, or mold cuz my air is humid and isn't moving around. But if you have these things, and you've got your grow room dialed in, you will never have to ventilate (except when indicated earlier). There is also something I read about recently called CEA (controlled environment agriculture). This is basically where you have a separate room that you vent the air from your grow room into, you scrub it, dehumidify it, cool it, CO2 enrich it, and send it on back in to your grow room. Completely sealed environment, and the only thing in your grow room are those big beauties. No heat from all that equipment in your grow room, especially if you're using something to generate your CO2. There was a 2 or 3 piece article on it in maximum yield, october 2009 issue.