Why does co2 hurt my plants!?

FilthyFletch said:

As explained Stagnant air is air that's just that stagnant. It is too high in one make up or another the co2 can be too high the O2 can be too low. The heat from the lights can react to the tent lining rooms paint, sealants, tape adhesive nutrient fumes a ton of things. As mention it is similar to after winter you cant wait to open windows and screen doors the air exchanged in general makes you feel better and happier which is the same low level life of a plant does the same.......Joe the big article you post pretty much backed what i was saying..It mention you can pay little attention and get some benefits but it does express the use of precise environmental control. When you vent your co2 levels only drop for a few minutes before the co2 kicks back in and brings the designated co2 set point back online ie the prime ppm level is the 1200 to 1500 ppm level...Some said they are running 2200 ppm which is way to high. It is wasteful and if not ever vented can become toxic to plants and humans as you smoother the plant. Its similar to in a non sealed room where you need to exchange the air also. fresh air and air movement make huge differences. With correct co2 usage you should see up to an 80% total yield increase and a week or more shaved off flower times... I have seen some add co2 in the veg state but I have never seen it really add much to the difference from just added during flowering time... I have seen some rooms run co2 in negative pressure grow rooms and not vent but that's a different monster.. Commercial greenhouses do run co2 and they almost all vent in and hot as that's also for temp control or they have had a/c units in them which does the same thing as an ac will suck the warm air from the room exhaust it out which outside air is sucked in over the condenser coil and cooled before being forced back into the room but in grow situations dampers will close off the vents when not running again sealing the area....If you have the time try setting 2 identical grows up. Keep one with co2 and zero air exchange and in the other set your co2 up and dampers with in an outtake fans so air gets replaced a few times even if just 2 times right right before lights on and right as lights go off. Compare the yields and the flower density it will be different. I first started playing with co2 about 15 years or so ago. I have worked in a commercial greenhouse which is where I learned most of the basics then over the years being friends with many indoor growers and medical grow op folks notes have been shared and lessons taught.. Some use tanks, some burn propane, some Natural gas, some use bacteria and yeast for small enrichment but the best and most attentive growers control the entire environment like hawks.. Again you can run just co2 no exchanges but your not going to run on all 8 cylinders just 5 of them meaning it can be much better. For me it was just learning when I wanted the exchanges then taking the time to watch time and cordinate the timers on fans, setting auto close/open damper and good ppm monitoring and control setup...To each grower their own I just am sharing my decades of use and teachings given to me so it's just out there for those who understand and use it I hope you enjoy it. Those who disagree that's also fine best of luck in your methods and I hope its all good and if your happy with it then your fine.

P.S On the sulphur topic it is a common practice to use sulphur burners to prevent and control mold it does not change the taste or even the natural aroma of the product. the fumes kill mold spores and the heat help control moisture so not sure why the one user was trying to say something bad about that as that's a very very long used technique.

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Merlin34 said:

Fletch is right. I worked at an industrial medicinal grow and yes the venting was on timers. I can't remember the exact times that the rooms were vented a day, several times during lights on. And they were always vented for longer periods right at lights on and lights off to fully vent the rooms. One of these rooms had 75k watts in it, so big rooms, granted our co2 tank was as big as a truck...

Sent from Northern Colorado.

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Aeroknow said:

I don't doubt anyone who doesn't periodically "dump" the room. I don't doubt some reasons why people do dump.
I've done both.

Just some reasons one mite think they need to dump:
Gassing off of building materials
Co2 gens burn O2 rite? Mite need to add back some lost O2?
Some people burn sulfer once in a while, then dump. Try it
Flame me, I don't give a rats ass

I've converted a few sealed rooms, and it helped with the overall health of the room, and increased yields. All the nay Sayers, please explain that

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joe macclennan said:

but plant's produce o2 during photosynthesis

i'm not trying to flame anyone here except the jackass hyroot. and i'm over that guy

and I can definitely see the benefit in venting after a sulfur burn for sure. For my physical comfort more than anything.

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joe macclennan said:

still looking. One source says once a day is sufficient most so far say no venting is necessary then there is this one. http://www.ngma.com/industry/Carbon_Dioxide_Enrichment.pdf CO2 Concentration and Plants Photosynthesis is the process of plants using light energy to convert absorbed carbon dioxide (CO2) and water into sugars. Plants use these sugars for growth through the process of respiration. Plants absorb CO2 through their stomatal openings located mainly on the underside of leaves. Although light, moisture, temperature and humidity levels all affect the rate of CO2 absorption, the concentration of CO2 outside the leaves is a significant influence. The concentration of CO2 in ambient outside air commonly varies from 300 to 500 parts per million (ppm) or more by volume depending on the season, time of day and the proximity of CO2 producers such as combustion or composting, or CO2 absorbers such as plants or bodies of water. Plants growing in greenhouses, particularly “tight” double‐layer structures with a reduced air infiltration rate, can reduce CO2 levels to well below ambient levels, greatly reducing the rate of photosynthesis. Conversely, enriching the concentration of CO2 above ambient levels will significantly increase the rate of photosynthesis. In general, a drop in CO2 levels below ambient has a stronger negative effect on plant growth than the positive effects of enriching CO2 levels above ambient. Daily CO2 levels in un‐enriched greenhouse environments will climb to several hundred ppm above outdoor ambient at night due to CO2 produced by plant and microbial respiration. CO2 levels drop quite rapidly after sunrise as the crop’s photosynthetically‐driven consumption of CO2 exceeds the basic rate of respiration. In the absence of some other source, CO2 levels remain low all day limiting plant growth. At dusk, plant and microbial respiration once again begins to accumulate CO2 in the greenhouse. CO2 is added in some greenhouses to increase growth and enhance crop yields. The ideal concentration depends on the crop, light intensity, temperature and the stage of crop growth. This document is intended to provide the basics of CO2 enrichment so growers, in conjunction with industry experts, can research the best options for their particular greenhouse operations. How is CO2 concentration monitored? Most growers do not monitor CO2 levels in the greenhouse because they have no intention of controlling it. As long as their crops are growing and developing to their satisfaction, this is a reasonable approach. CO2 levels in the greenhouse may be monitored using relatively low‐cost dual beam infrared CO2 gas monitors. These monitors may be linked to climate control systems that integrate other factors such as indoor & outdoor air temperature, humidity & light intensity. More expensive monitors with higher accuracies are available, but in most applications reliability and economical cost are the most important factors. Although basic CO2 dosing may be applied without monitoring CO2 levels, the relatively low cost of a good CO2 metering system pays for itself in the form of cost savings from supplemental CO2 sources. When is CO2 enrichment needed? CO2 enrichment is not required as long as the crops are growing and developing to the complete satisfaction of the grower, or if high ventilation rates make CO2 enrichment uneconomical. CO2 enrichment should be considered, however, if crop production and quality are below required levels. In general, crop production times from late fall through early spring increases the potential need for CO2 enrichment as it coincides with reduced ventilation rates due to colder outdoor air temperatures. As ventilation rates are increased for cooling and dehumidification from late spring to early fall, the cost of CO2 enrichment escalates while the benefit to the crop may be minimal or reduced. As photosynthesis and CO2 consumption happens only during daylight hours, CO2 enrichment at night is not required. In general, CO2 enrichment systems should be turned on 1 or 2 hours after sunrise, and turned off several hours before sunset, however, additional CO2 enrichment may be needed if supplemental grow‐lighting is used. How are CO2 levels enriched? 1. Maximize Natural (Free) CO2 Supply: Maximize ventilation rates whenever possible starting 1 or 2 hours after sunrise when the overnight build‐up of CO2 has been depleted. Improve horizontal air flow to distribute available CO2 evenly throughout the crop and to reduce the leaf boundary layer, which will improve the diffusion of CO2 into the stomatal openings of each leaf. Keep plants healthy and well‐watered so they are not forced to close their stomatal openings due to stress. Depending on the crop, consider using natural sources of CO2 such as decomposing straw bales and/or organic soil mixes in your production system. 2. Liquid or Bottled CO2 Gas: When outside air conditions are too extreme for ventilation, additional CO2 is available in the form of liquid or bottled CO2 gas. Specific processes are required for the safe & proper handling as well as the effective use of CO2 from these sources. Liquid CO2 must be fully vaporized before delivering into the greenhouse, and manufacturers’ instructions and local codes should be strictly adhered to. 3. CO2 from Carbon‐Based Fuels: Gas‐fired appliances generate CO2 and water vapor as primary byproducts of combustion. These appliances include equipment that is specifically designed & certified as CO2 generating appliances, un‐vented forced‐air primary space heaters, and hot water boiler heating systems with flue gas condensers specifically designed for CO2 enrichment. Achieving complete combustion is the key to success of CO2 enrichment through appliances burning natural or propane gas. Incomplete combustion may occur due to relatively common factors such as improper or fluctuating gas pressure, impurities in the gas supply, inadequate oxygen for combustion, wind disturbance in the burner and clogged gas orifices. Harmful byproducts of incomplete combustion include Nitrogen Oxides, Carbon Monoxide and Ethylene. To increase the likelihood of complete combustion, it is recommended to use only gas‐fired appliances that are certified by 3rd‐party testing agencies (CSA, ETL, UL, etc.) to meet nationally recognized safety standards. Agency‐certified appliances should only be used for the applications that they are certified for, and the appliances should include installation, operating & maintenance instructions with the product. These instructions should be strictly adhered to and saved in a convenient place. As water vapor is also a primary byproduct of combustion, un‐vented gas appliances have the potential to create difficulties in the naturally humid greenhouse environment. Condensation due to high humidity promotes many plant diseases. Condensation from combustion is also slightly acidic, which may prematurely corrode metal structures, equipment and wiring on contact. Building codes and manufacturers of un‐vented gas appliances typically require minimum rates of air changes in the greenhouse per volume of fuel burned. Although introducing fresh outside air will increase greenhouse heating costs in colder weather, these ventilation rates are necessary to ensure adequate supplies of oxygen for complete combustion, and to prevent the build‐up of unwanted water vapor and/or contaminants due to incomplete combustion. NGMA Helpful HintsIs CO2 enrichment safe? CO2 is harmless to humans at all reasonable dosing levels, and OSHA has established workplace standards for worker exposure. While humans can work safely at these elevated CO2 levels, many crops start to show undesirable growth responses at CO2 concentrations above 1,200 to 2,000 ppm. For gas‐fired CO2 generators, adequate ventilation air should be introduced to provide enough oxygen for complete combustion, and to limit the build‐up of water vapor and other potential contaminants in the greenhouse. General Tips & Conclusion CO2 enrichment can be a useful tool for maximizing the quantity and quality of your greenhouse product. Healthier crops and higher yields helps to satisfy customers, command higher prices and reduce costs, all of which makes a greenhouse operation more competitive. The decision to proceed with CO2 enrichment should follow a thorough cost/benefit analysis, and success depends on each grower developing a strategy based on their unique combination of greenhouse structure, crop type, local weather, stage of production and capital/operating budgets. Once a CO2 enrichment strategy is selected, always follow the instructions and installation & service manuals of equipment and/or chemical manufacturers. Make sure national and local codes covering greenhouse operations are adhered to, and use qualified & experienced service agencies and technicians for installing and maintaining CO2 enrichment systems. Reviewing these Helpful Hints and gathering more information from available horticultural industry experts and resources will help you make informed decisions, and enhance any CO2 enrichment strategy’s effectiveness. For more information, please contact: National Greenhouse Manufacturers Association 717‐238‐4530 or info@ngma.com NGMA Help not calling you a liar fletch. but this doesn't back your opinion up. I'm still looking though. do you have any ideas for where I can read this opinion elsewhere? an accredited source?

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joe macclennan said:

ok so i'm gonna go vent my co2 enriched room right now. BUt only because I have to go in there to do some work. I'll be back and will certainly research this further.

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joe macclennan said:

a flip box could easily do that...or a cycle timer on a photosensor. some of the atmospheric controllers can do some pretty complex actions too. i'm still not convinced this is the correct thing to do though. because a few members have seen it done on large scale medi grows still isn't a home run for me. i'd like to see something more concrete. like an accredited study. WHich I am still searching for

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Merlin34 said:

And Joe, I'm not saying that I'm right. I'm just stating how it was done where I worked. I never asked why... I just figured that's how it was always done. Sent from Northern Colorado.

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Red1966 said:

I'm afraid I can't put any faith in that article at all. The author talks of liquid co2 in a bottle. There is no liquid phase of co2. co2 can only exist as a gas or a solid. Generally, when you see one glaring inaccuracy is an article, the rest of the article becomes suspect. I believe venting a sealed co2 enriched room is just wasting co2. I can agree that venting during lights off, assuming the co2 is also off, may be helpful. The plant itself produces oxygen during lights on, more than exchanging air does. I suspect the OP has overlooked some other problem that just happened to coincide with enriching the co2. Pathogens attacking the roots, pH problems, root zone temps, or something. I have never heard of anyone else having this problem, tho that doesn't prove it has never happened. It could just be that I'm a mushroom.

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joe macclennan said:

well that's cool man. I'm not saying I'm right either. Only that almost every piece of written text on the subject says otherwise except for the one and it suggested once a day venting not several times ....that I have found so far. I need to expand my search though. It would be easy to assume that someone setting up a 75k + grow would have their p's and q's in order.....but I have seen similar operations around here poorly ran as well. Granted none quite that large but pretty large anyway. just because someone had the cash to start something like that doesn't make them an expert...that's all i'm saying. and I'm certainly not one either.

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joe macclennan said:

running co2 24/7??? well if that isn't wasteful I don't know what is. what is the purpose of running them at night?

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kinddiesel said:

I think is impossible to hurt plants with co2. I have seen grow rooms with there ppm up to 5500 ! that's stupid high cant breath . but there plants are looking good. in my opinion that's to high because plants roots breath o2. but the farmer likes the results from it. standard co2 depends where you live 300 to 900 in new York. smog

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hyroot said:

o2 is good for roots. why in the world would you burn sulfur?

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joe macclennan said:

the room is sealed and the building is very tight and in a steel building. I battle mold and shit on the walls constantly during winter. due to condensation. sulfur burners work excellent for this. Also I have root aphids and being perpetual they are near impossible to eradicate. The sulfur burn helps to prevent fliers thereby reducing their spread from tray to tray. I assure you that after 3-4 days under 60w/sq.ft and as much air circulation that I have that the sulfur has all dissipated and does not effect the quality or taste of the product......otherwise i'd hear about it. knock wood I have never had any pm or mold of any sort on my colas....thank god.

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