Air exchange -- two rooms, 1 co2.

[HannaMan]

Hey.

Recently bought a Gen2. Building one big room into a veg and flower room.

If I have the gen2 in the large flower room, can I have a passive intake/exhaust on the veg room, just recirculating SEALED co2 air in / out of the veg room.

 

[Kieserblade]

I don't know the best answer for you, but here are a couple of things to consider. A single 2X2ft plant can use C02 at 1500ppm in a 4x4x8 ft space, if it is a sealed room.
Dry air (and in most indoor grow rooms) contains roughly (by volume) 78% nitrogen, 21% oxygen, 0.93% argon, 0.038% carbon dioxide. (this is more or less at sea level and 70 degrees F)
At standard temperature and pressure, the density of carbon dioxide is around 1.98 kg/m3. That is about 1.5 times the weight of the air in your grow room air.
So you should consider distributing your CO2 from the highest point in your room directly over your plants because it is so much heavier than air. Just make sure the hose is not close to your exhaust-pull-fan because you’ll suck out all of your precious CO2! Another thing to consider is that you are probably bumping your CO2 rate by volume to close to 2000ppm. This adds about 5 times the amount of Carbon and Oxygen atoms into the air which is now the equivalent weight to a strand of hair falling through air.
So I don’t the physics will allow a passive-recirculation system, especially if the room is larger than what a 4x4x8 space can naturally use with (5 or 6) plants.
You could consider a simple oscillating fan at the lowest point in the room at the base of your plants and some duct work to push any unused C02 to the other side of your room. But your best bet is what I ended up doing and just regulate 2 bottles (one in each grow room) Yes – it’s expensive but I’ve seen way too many grows with week CO2 yield only 2 or 3 Oz per plant. And seen one plant (white widow) produce over 1lb. (dried) when the CO2 is dialed in. Also remember that at over 3000ppm your CO2 can be toxic to your plants. And if you for some reason you push more than 10,000ppm in your sealed grow space you’ll get one hell of a headache and maybe even pass out!

 

[HannaMan]

Thanks for all the information brotha.

I purchased the Gen2 w/ extra burners..my room isn't going to be 4x4 but more so 24x24.
I will be hanging it from the roof directly above my flowering plants.

The truth is, my main concern is not to get the co2 into the veg room but just to have fresh air exchange in the veg room. The reason for the passive intake is to allow the co2 to get sucked up by my flower plants before being sucked into the veg room.

With vegging plants, how crucial is large amounts of co2? I have seen plants veg fine in a room with just oscillating fans, no co2/exhaust.....but I dont wanna settle for "fine" - I want to do it right.

The reason for this is because outside temps are way to high, so i would rather just recirculate the clean sealed air.

Any input?

Thanks again!

 

[Kieserblade]

Wow… nice room. I would love to have a garden space that size. In Texas I have the same outside temp problems so I have to make do indoors. But one day I envision a massive 100 plant outside greenhouse nirvana on the back side of Lake Travis in Austin! I am however convinced that co2 in the veg room takes the finished flower to the highest quality levels. I believe (after many experiments with and without) that co2 at 15000ppms in a veg room is essential for stronger root systems and a little quicker vegging (say… 4 weeks down to 3 and a ½). But the biggest advantage I’ve seen is more in the taste. I don’t think it affects yield, at least non that are noticeable. But my crew and I all believe that there is a MUCH higher flavor quality if the buds are grown out of shoots that have been vegged in high amounts of co2. We have a connoisseur club of about 7. Every quarter or so, we get together and sample each other’s fruit! And we all have gone to using 15000 to 18000 ppms of co2 in our veg rooms because we swear it makes the smoke more flavorful and robust. I know technically the covalent bond between Oxygen atoms and Carbon atoms has the same effect on a pre-popped calyx as is it does on a growing stem. But I think the higher levels of co2 early in the plant's life development creates a "heavier" sugar for the buds to feed off of during flowering. We think vegging in co2 makes more of a dense sugar storage in early photosynthesis so when you switch to your photo period the plant pulls more of the fructose enzymes than the sucrose form of the energy polymers. There is a guy in our group who is about to start his seedlings in a vacuum, using pure co2, just to see how it finishes in a super control group! I know it’s over the top but he’s really got nothing else to do… Any way I hope this helps or at lease gives you some creative ideas for your room. Peace.

 

[HannaMan]

Hey man. That is awesome help. I'm all about a super strong + healthy veg, without that and I feel like you're wasting your time by making the flip.

With using only 1 co2 gen, how can I assure my veg room is getting adequate amounts of co2.

I guess im going to have to do some re-thinking, re-designing on the veg room..
Thanks for all the great help! I look forward to seeing your huge green house :)