Co2 questions from a complete noob - Show me your experience!

[SoCaliSmoker]

Please help answer the questions and not just read my thread. I try to answer questions when I can on other members threads, so help a fellow grower out! This thread is kind of long but damnit I'm serious!

I've never used Co2 before and everyone has something different to say about it. I'm not a first time grower, just a first time Co2 user and I don't want to mess everything up but I'm scared I'll do everything wrong by all the different things I keep reading from all kinds of different sources.

Let me start out by saying - I AM NOT ON A BUDGET!!!! No DIY with yeast, or dry ice, all questions are Co2 tank questions. All my grows I've ever done have been Ebb and Flow, 4ft by 8ft trays, 2k HPS lighting and using Rockwool.

I've never complained about my harvests as I've always seemed to get a pretty good yield on some kick-ass dank chronic but everyone wants to know how to get a higher yield and it seems that Co2 is my only way.

For my next setup (all equipment is purchased) I'm going to do the following setup:

2/ 4ft X 8ft trays
6/ 600w HPS lights (3/ 600w lights over each tray)
16 X 20 ft grow room with 11 foot ceilings
All the other good stuff (sealed room, fresh air intake, exhaust, A.C, yada,yada,yada)

I "understand" the following when it comes to Co2:
PPM and maximum growth at 1500ppm (all my questions are during flowering), Co2 regulators, calculations, where to buy equipment and where to fill them up, and how long during flowering I should be using Co2 before I stop adding Co2 to the grow room. This I understand.

What I don't understand is "when" I'm using Co2:

How many times a day do I add Co2 to my grow room?

If I use it 4 times a day (for example, I don't know how many times I'm supposed too) how long do I let it run for? 30 secs, 45 secs, 1 minute?

I keep reading you have to turn your fans off when Co2 enrichment is happening. How hot does my damn room get? Is this healthy for my plants, that kind of heat can get my grow room boiling in no time!

Do I leave my oscillating fans on and turn off my A.C? Do I leave my A.C on while Co2?

If everything is on, and Co2 is falling, do I just turn off my exhaust fans temporarily until I'm ready to turn it back on?

HOW THE HELL DO PEOPLE USE CO2!!

I can understand that Co2 is a great thing and if used improperly (exceeding 1500 - 2000ppm could be disastrous for my plants) but I just don't understand how it works when it's working. Am I completely off track here and it's really simpler than I'm making it? Please help in anyway possible, I can't just ask some dumb ass that works at a Hydroponic store. His or her judgement means nothing to me as it could ruin my whole crop.

I get great yields without Co2, but I don't want to sit and wonder what it would have been like to get 15%-35% more and I don't give a damn about the money. Please help advise and there is no such thing as a wrong answer here. I'm sure the credibility on IC is much better than asking a buddy. Thanks guys (and ladies)

 

[Lazyman]

Please help answer the questions and not just read my thread. I try to answer questions when I can on other members threads, so help a fellow grower out! This thread is kind of long but damnit I'm serious!

I've never used Co2 before and everyone has something different to say about it. I'm not a first time grower, just a first time Co2 user and I don't want to mess everything up but I'm scared I'll do everything wrong by all the different things I keep reading from all kinds of different sources.

Let me start out by saying - I AM NOT ON A BUDGET!!!! No DIY with yeast, or dry ice, all questions are Co2 tank questions. All my grows I've ever done have been Ebb and Flow, 4ft by 8ft trays, 2k HPS lighting and using Rockwool.

I've never complained about my harvests as I've always seemed to get a pretty good yield on some kick-ass dank chronic but everyone wants to know how to get a higher yield and it seems that Co2 is my only way.

For my next setup (all equipment is purchased) I'm going to do the following setup:

2/ 4ft X 8ft trays
6/ 600w HPS lights (3/ 600w lights over each tray)
16 X 20 ft grow room with 11 foot ceilings

All the other good stuff (sealed room, fresh air intake, exhaust, A.C, yada,yada,yada)

A sealed room typically has no intake or exhaust, unless used for emergency overtemp issues. For example, if your AC quit, and the room got hotter, fans could kick on to exhaust the room.

I "understand" the following when it comes to Co2:
PPM and maximum growth at 1500ppm (all my questions are during flowering), Co2 regulators, calculations, where to buy equipment and where to fill them up, and how long during flowering I should be using Co2 before I stop adding Co2 to the grow room. This I understand.

What I don't understand is "when" I'm using Co2:

How many times a day do I add Co2 to my grow room?

You shouldn't be doing this manually, use a CO2 controller like the CHHC-1 that will maintain optimum levels for you, turn off at night, and will kick off if the room gets too hot. This last feature is better for CO2 generators but you may move to a genny later.

If I use it 4 times a day (for example, I don't know how many times I'm supposed too) how long do I let it run for? 30 secs, 45 secs, 1 minute?

See above

I keep reading you have to turn your fans off when Co2 enrichment is happening. How hot does my damn room get? Is this healthy for my plants, that kind of heat can get my grow room boiling in no time!

Ideal lights on temp for CO2 sealed rooms is 85* F. If you use air cooling for the room, you'll be blowing this expensive gas right back outside.

Do I leave my oscillating fans on and turn off my A.C? Do I leave my A.C on while Co2?

Oscillating fans should never turn off. AC should always be ON too, just set to 85 or whatever it takes to KEEP your room at 85 with the lights on. I like my night temps to go down to about 70, better purpling that way.

If everything is on, and Co2 is falling, do I just turn off my exhaust fans temporarily until I'm ready to turn it back on?

HOW THE HELL DO PEOPLE USE CO2!!

Check out the online manual (pdf) for that Sentinel controller above, it will answer how this all works. In short, the controller controls the fans and CO2, as well as temp and humidity levels.

I can understand that Co2 is a great thing and if used improperly (exceeding 1500 - 2000ppm could be disastrous for my plants)

Plants can use quite those levels, higher levels won't really harm the plants, but it does waste expensive CO2.

but I just don't understand how it works when it's working. Am I completely off track here and it's really simpler than I'm making it? Please help in anyway possible, I can't just ask some dumb ass that works at a Hydroponic store. His or her judgement means nothing to me as it could ruin my whole crop.

Most of em don't know much about it.

As the room gets hotter, the stomata (breathing holes in the leaves) open wider so the plant can breathe more, trying to cool itself. It will take up more water and more food, but if you add more CO2, it will inhale that too. It helps photosynthesis and makes the plant grow faster (faster cell construction.)

I get great yields without Co2, but I don't want to sit and wonder what it would have been like to get 15%-35% more and I don't give a damn about the money. Please help advise and there is no such thing as a wrong answer here. I'm sure the credibility on IC is much better than asking a buddy. Thanks guys (and ladies)

You're on the right track, there are lots of good articles if you use google on CO2 enrichment, but the above is all that really matters for us indoor growers.

Have a good one!

 

[Lazyman]

Oh, and read this thread, it should help:

http://icmag.com/ic/showthread.php?t=141160

 

[sparkjumper]

Let me just say if you want a steady 1500PPM without much fluctuation you need a co2 controller,going with calculations really just doesnt get it.They dont take into account a number of important things like number a size of plants,what stage of 12/12 they are in.among other things.Get a co2 controller man even a cheap cap PPM-3 makes a world of difference in trying to enrich a room and keep it steady

 

[SpasticGramps]

With a setup like that, I'd get a generator and a good controller. That will keep your CO2 at a constant 1500-1600ppm. Forget tanks, unless you don't mind going and picking one up all the time. I would find that a huge hassle personally, but some don't seem to mind. And trying to time CO2 release with a timer is nowhere near precise enough environmental management for me.

I have the HydroGEN Pro Generator and the Green Air Setpoint as my controller. It's supposed to keep the room within 20-50ppm's. I'll be hooking it all up here in the next couple of days and will write a report on the combination. If you go with the HydroGEN Pro most people on here and my grow shop guys said running it drain to waste (DTW) is the only way to properly do it.

 

[SoCaliSmoker]

Thank you guys so much, this is exactly what I was looking for. I knew that it had to be easier than I was making it. Just another question, ideal temp for the room with Co2 should be 85* as Lazyman stated above and I've read in other columns but does that cause my plant to strech a little bit?

I've noticed when my grow rooms have gotten to about 88* the plants still grew but they stretched out. Is it possible to set my room to 80* AND use Co2 at the same time? Or is there a reason the temp should be at 85*? Just asking..

Thank you for your replies!

 

[LEDGro]

I have never used a HydroGEN but the manual shows a few other ways to use it instead of drain to waste. Im not sure how effective they are but I don't think they would list methods that don't work.

 

[LEDGro]

Thank you guys so much, this is exactly what I was looking for. I knew that it had to be easier than I was making it. Just another question, ideal temp for the room with Co2 should be 85* as Lazyman stated above and I've read in other columns but does that cause my plant to strech a little bit?

I've noticed when my grow rooms have gotten to about 88* the plants still grew but they stretched out. Is it possible to set my room to 80* AND use Co2 at the same time? Or is there a reason the temp should be at 85*? Just asking..

Thank you for your replies!

There have been studies that show when you add CO2 plants tolerate heat better. If you have high temps and no added CO2 it can be an issue but when supplementing higher temps are ideal.

Why not just try slowly increasing your temps and see how the plants react once you have your CO2 in place?

 

[sparkjumper]

There is a reason you want 85F as minimum actually,MTF Sandman used to run 90F.When you raise temps you are raising the plants metabolism its working extra hard to grow provided there are no other limiting factors like lack of light.Get a little lazer thermometer they come in so handy with everything.I have fluke 62 mini.Use a lot of ferts expecially nitrogen the first 3 weeks during the stretch

 

[SoCaliSmoker]

Great information!!! I understand now what the increase in temp does and why it is necessary when Co2 is present. As I had mentioned before, I've never used Co2 and I've had grow rooms reach as high as 91* and all it did was make my plants stretch. That was before I spent the money to make sure my optimal temp was always set and I never look back now when there is money to be spent on my ladies.

It has been mentioned a couple times that a Co2 generator is probably going to be the best method (or the only method for this) that I should be considering. Any suggestions on Co2 generators or systems? Something that is user-friendly or something that you've used and are happy with? I don't mind the price, please suggest any system and I'll look into it thoroughly.

Thank you for all your responses!!!!

 

[SpasticGramps]

I have never used a HydroGEN but the manual shows a few other ways to use it instead of drain to waste. Im not sure how effective they are but I don't think they would list methods that don't work.

You can, but those pumps you get at the hydro store won't do it. You would need a big ass sump pump *think pond pump* to get the right psi to make it fire consistently. Everything I've read on here and everyone I've talked at my grow shop said while technically you can. It really doesn't consistently unless you are doing DTW.

 

[SpasticGramps]

Great information!!! I understand now what the increase in temp does and why it is necessary when Co2 is present. As I had mentioned before, I've never used Co2 and I've had grow rooms reach as high as 91* and all it did was make my plants stretch. That was before I spent the money to make sure my optimal temp was always set and I never look back now when there is money to be spent on my ladies.

It has been mentioned a couple times that a Co2 generator is probably going to be the best method (or the only method for this) that I should be considering. Any suggestions on Co2 generators or systems? Something that is user-friendly or something that you've used and are happy with? I don't mind the price, please suggest any system and I'll look into it thoroughly.

Thank you for all your responses!!!!

Do you have someplace where you can easily plug into a city water line? Shower, sink, in your growroom. If so the HydroGEN Pro DTW has great output and is water cooled so some of that heat is getting removed.

Green Air and Sentinel make good generator too that I looked at. But since they are not watercooled they will produce more heat that has to be compensated with a/c.

 

[SpasticGramps]

Kind of a side not question. I forgot what the answer was. Does anyone know off the top of their head the maxium leaf temperature you can have before photosynthesis stops? Isn't it like 80 or 82 (speaking out of my bumhole a little bit there). I have an infrared temp gauge to check the leaf temps.

 

[SoCaliSmoker]

"Kind of a side not question. I forgot what the answer was. Does anyone know off the top of their head the maxium leaf temperature you can have before photosynthesis stops? Isn't it like 80 or 82 (speaking out of my bumhole a little bit there). I have an infrared temp gauge to check the leaf temps."

I would probably ask Lazyman a question like this. He is a guru when it comes to technicalities. The guy is unreal - thanks for all the help!

 

[sparkjumper]

I know with high co2 levels the leaf surface reaches 85 or more but I'm not sure with regular co2.I would go with a generator I use the Green air CD-6 which is a pretty small single burner for an 8 by 8 by 8 room.You must find out your cubic footage and size your generator from that

 

[Lazyman]

Here, maybe this will help:

Abstract To determine how parameters of a Farquhar-type photosynthesis model varied with measurement temperature and with growth temperature, eight cool and warm climate herbaceous crop and weed species were grown at 15 and 25 °C and single leaf carbon dioxide and water vapor exchange rates were measured over the range of 15 – 35 °C. Photosynthetic parameters examined were the initial slope of the response of assimilation rate (A) to substomatal carbon dioxide concentration (Ci), A at high Ci, and stomatal conductance. The first two measurements allow calculation of VCmax, the maximum rate of carboxylation of ribulose bisphosphate carboxylase and Jmax, the maximum rate of photosynthetic electron transport, of Farquhar-type photosynthesis models. In all species, stomatal conductance increased exponentially with temperature over the whole range of 15 – 35 °C, even when A decreased at high measurement temperature. There were larger increases in conductance over this temperature range in the warm climate species (4.3 ×) than in the cool climate species (2.5 ×). The initial slope of A vs. Ci exhibited an optimum temperature which ranged from 20 to 30 °C. There was a larger increase in the optimum temperature of the initial slope at the warmer growth temperature in the cool climate species than in the warm climate species. The optimum temperature for A at high Ci ranged from 25 to 30 °C among species, but changed little with growth temperature. The absolute values of both the initial slope of A vs. Ci and A at high Ci were increased about 10% by growth at the warmer temperature in the warm climate species, and decreased about 20% in the cool climate species. The ratio of Jmax — VCmax normalized to 20 °C varied by more than a factor of 2 across species and growth temperatures, but differences in the temperature response of photosynthesis were more related to variation in the temperature dependencies of Jmax and VCmax than to the ratio of their normalized values.

°F =(9/5)°C+32

 

[SpasticGramps]

If I'm reading this correctly.

The experiment tests CO2 uptake and water vapor exchange between 59-95F.

The optimum range for assimilation of high concentration of CO2 (which is what we are trying to accomplish) is between 77-86F. The effect is more pronounced in warm climate species. However, stomatal conductance was exponential from 59-95F even when assimilation rate decreases.

Here's my question. How are they defining measurement temperature (room temp?) and growth temperature (leaf temp?). Is this speaking to environmental temperatures or leaf temperatures?

 

[sparkjumper]

Thats always been a question I've wondered about,are we talking about 85 F at the leaf surface or 85F ambient temps(Temps surrounding the plants).I've always pretty much gone with ambient temps shooting the wall nearest plants or the floor and just doing the best I can. One thing I've noticed is leaf temps are a good 4 to 5 degree difference depending on how hydrated the plant is.Thats another reason I try and go with ambient temps.A fully hydrated plant may read 80 leaf temp and three days later without moving either light nor plant,leaf surface may read 84-85

 

[Lazyman]

Hey guys, these experiments were done measuring ambient room temps, leaf temps shouldnt be much higher than ambient unless your lights are too close to the canopy, but as a standard we should all use ambient room temps. Checking leaf surface temps is only easily done with a laser thermometer.

 

[SpasticGramps]

Hey guys, these experiments were done measuring ambient room temps, leaf temps shouldnt be much higher than ambient unless your lights are too close to the canopy, but as a standard we should all use ambient room temps. Checking leaf surface temps is only easily done with a laser thermometer.

That's what I figured. I read somewhere in Dongle's thread that photosythesis stopped at a certain leaf temperature. I might get motivated enough to go dig through that thread and find it.

I'm somewhat anal retentive and love things that measure shit. I use this to measure my leaf temp. BTW this is over excessive and you don't need to do it. Like Lazy said, keep your room at 85 and lights a couple feet above and it shouldn't be a problem. I like my toys.