Hi all, and thanks in advance to anyone who can answer a few questions I have that I can't seem to get a definitive answer to... 1) I read tonight on these forums somewhere that in the flowering room temps should be kept at or below 70 degrees. Is that right? Most things I read say that temps should be 74-76 ideally, whether vegging or flowering. I also read i na gardening book that if using co2 in the flowering room, that higher temps (80-82) will make the co2 lots more effective... What's the real deal for good temps both vegging and flowering? 2) I see written everywhere that the air in a growing room (if a veg room or a flowering room not using co2) should be replaced once every 5 minutes. Is there any way to accomplish this by turning the extraction fan on for 1 minute only once every 5 minutes? (My extraction fan can bring a roomful of fresh air in in about 30 seconds). Or does one simply leave the extraction fan on 24/7? All the timers I see out there are only programmable every 15 minutes, and the digital ones are minute by minute but everything I've seen there is a maximum of only 8-12 programmed timings, about enough to do it for 1 hour. What's the recommended way to take care of this? Do I have to leave it on?
1. Ideal temps would be mid 70's, but they can thrive in anything from 70 to almost 90 degrees. Think of some of the places MJ grows outside, gets VERY hot and humid in some of those places. My tent temps range from 76 - 80 and I am doing just fine. Thats just the rating on how powerful the fan is. And yes, its best to leave the fan on 24/7 to allow constant fresh air in the grow environment. Its ok if yours is every 30 seconds, just leave it running. About C02. I would not even worry about it. Itrs not just about the higher temps. You need to control the amount of C02, your grow environment should be a sealed environment or else the C02 is wasted. Don't even worry about C02. Keep everything else on track with your grow, and you will do great.
^^Agree...If you were to add co2 in your grow you would want to put a timer on the exhast so as to not exhast all the co2 used by the plant. C02 also works best at higher temps
Fakename!?? Mee too. HA! I'll try and answer #!.. My room is in a centrally AC'd home that is set at 73*F.. In that room is my box/cabinet, it runs a 600w HPS and CO2. Additionally, there is a portable AC in the room, set at 69F, 24/7. With above setup, temps run 86F in the box with an aircooled hood, water temps are 71. If I were to run the grow without the portable, the lights, pumps and chiller would cause the room temps to go into the mid to high 80's within the room, humidity would be off the charts and box temps would easily be 90s. Water temps in the rez would be 80 or so... and gnats, root rot and other nasties start to appear in the mid 70*sF. When temps go up, buds get 'airy' not dense, plants stretch more and groth is slowed. #2.. air circulation.. you would have to have a very big fan to change the air in a room in 30 seconds but it is not impossible. A 265cfm fan can, according to the manufacturer will move 265 cubic feet per minute. Pure math says a 10'x10'x 8' room is 800 cubic feet (I think), 800/265=3. So ideally, you would changee th air in 3 minutes with that fan... realiity, it might take 15-20 minutes to make a complete change... air exchange is a PITA. Any additions to the intake or exhause of the fan will also lower the CFMs of the fan, makeing it even less efficient. Bigger fan = better. GL
Thanks for the reply... You run a a/c in the room with the co2 enhancement? Is it dual-hose? I have been trying to figure out if a sual hose portable a/c will do the trick... I read that dual-hose uses outside air, but no mention anywhere of whther or not it exhausts any room air outside (and the co2 with it)...
is there a magic number for "higher temps"? Right now, with my lights on, extraction fan off and co2 going, I am at about 85-86 degrees, it just seems too hot, especially under the (air cooled) hood. I read in a ton of places 85 is too high, but then again I see many people say it's best over 80... my hydro gardening book says 78-80... This users says 85-95: http://forum.grasscity.com/indoor-growing/303232-sealed-room-heating-issues.html post #8 and #21... This user says 85: http://forum.grasscity.com/indoor-growing/641465-co2.html post #4
The co2 goes into my 'sealed' box. The box is in the room. I'm guessing any excess co2 is vented out either the portable a/c or the central air return, 'I' can't smell it, too much, any more... but it smells but the portble is a one hose that exhausts into the garage (I cut a hole in the adjacent wall) where there is an ozone generator running... My neighbors haven't 'commented'. If smell is your worry, and it is a valid worry, co2 is only going to make it worse.
nah my worry is that putting an a/c in my flowering room (which i need to do, temps are getting up to 87 in there), co2 enrichment is pointless since the a/c will be sucking it in and exhausting a lot of it... thanks for your replies... if u want, check out my grow room project http://forum.grasscity.com/grow-room-design-setup/644657-basement-grow-room-space.html
No experience growing, but I've read in the "Marijuana Grower's Insider's Guide", that high temps decrease potency.
I run an AC in my room and have it set on recirculating mode so it is not constantly exhausting my CO2 enriched air. I also run a controller that has temperature controls on it which kicks on a fan when the temperature gets above a certain point. You might want to consider one of those as opposed to using a timer. Temperature will rise quicker than your CO2 levles will be depleted, and would serve as a good indicator of when a good time to exhaust would be. CO can increase your yield by 20%, more if you know what you are doing. I would not discourage from trying to fit CO2 into your grow. Name one other thing you can do with a grow that will make a 20% yield difference assuming all other factors are relatively stable
thanks for the reply. do u mean 85-86 would be "optimal" if using co2? Or would it still be better, even if using co2, to try to keep it below 80?
yes, 86 is good with the co2, I've heard others talk about going to 90*F. The controller, we did talk about a controller didn't we, would shut the co2 off, when the exhaust is on and then turn it back on when room is exhausted.
Just a wall unit that I close the vent on. There might be some appreciable air loss, but whatever, I 'm not worried about it. Just enjoying watching my juicy ladies enjoy their CO2 sandwhich A general temp/ventillation control unit is really helpful, they are around 150$, but it integrates your lights, ventillation, temperature control, and CO2 into a signle control unit that makes it really easy. IT is not a CO2 monitor, but just coordinates all of these things for your grow cycle. Mine simply cuts power to the CO2 system when the lights are off.