Is there a period when co2 is not beneficial?

Discussion in 'Advanced Growing Techniques' started by matty3580, Nov 16, 2011.

  1. I have a pretty solid foundation of plant basics and growing. I was recently reviewing the MMAR application for designated growers in Ontario and one of the questions asked:
    If CO2 is being used, during what weeks of the growing cycle is it not necessary or in fact, detrimental to crop health? What is the maximum CO2 ppm you should ever have in your room?

    I was of the impression that co2 is beneficial at all stages of growth. Of course as long as lighting, nutrients etc. are all increased to supply the plants growth.

    If anyone could shed some light on this for me that would be greatly appreciated. Thank you very much in advance and I hope to hear from you soon.
  2. not ever detrimental within good levels
    during night, complete waste -- only run tank during daylight
    most folks like 1200-1400PPM, about triple the atmosphere
    plants ability to utilize CO2 goes up with temp, keep your garden in the 80s
    i think toxicity is about 1800-2000PPM
  3. Ya the only thought I have is that the co2 might not get used anytime you weren't providing full nutrients(for the plants size) or full intensity lighting. Such as with young clones and seedlings or at the end of flowering when your plants are receiving no nutrients. But then I can't really see how that would be detrimental to the plants. It would just mean that the co2 wasn't getting used.

    Thanks for the quick reply I appreciate that.
  4. Being as I only use CO2 during flower, all the way up to harvest, I am not 100% sure. However if I had to give an opinion I would say during germination and seedling stages. The reason for this being the same as why you wouldn't give a seedling 1300 ppms or put it within 2 feet of your 1k HPS: it would probably stress the hell out of it.

    El Dorado is correct too about CO2 being wasted at night, the plants actually use some O2 at night to complete the respiration process but do not use any CO2. Adding supplemental O2 though would be pointless as the amount used is very minute.

    Good luck with the rest of your application and I hope it gets accepted!!

    Happy Growing ~23
  5. as they said above when the lights are off

    use O2 for the night cycle of you really want to get crazy about it because a botanist friend of mine told me that plants actually consume oxygen at night

    as I have said in other posts he has built test rooms for nasa (as well as like 200 other people so its not that special) for mars missions and he said that they use a CO2 mixture that would make a human pass out without a face mask on and oxygen to breathe because most of what is grown is 24 hour lighting but for the stuff thats got to flower he said they slightly increase the oxygen in the room during the night cycle about 10psi over pressure

    you could get one of those machines that is used for old people who cant breathe that makes compressed oxygen out of normal air and not have to get O2 tanks - but really you could just get lots of fresh air in there
  6. Thanks for the well wishes there strain. I am hoping everything goes through quickly and easily too.
    haha your botanist friend sounds like a very good friend to have their kidney. His input on topics is invaluable I am sure. I am kindof jealous haha.
    I understand how CO2 is used in photosynthesis and that it is only beneficial when the lights are on.
    It is frustrating because I can't find any readings anywhere or anything. I guess I will just have to keep reading the grow books until I find an answer.

    Thanks for the help guys it is greatly appreciated.
  7. There was an article in high times a couple of years ago that said during the last two weeks high co2 can reduce potency.

    That could be what they are referring to.
  8. Thank you mile. I was looking through the high times grow articles last night and found our answer. In an article it mentioned that CO2 shouldn't be used during the last weeks of the flowering stage. This is because at this point the buds are producing ethylene to ripen and the CO2 limits the amount of ethylene they produce. The plants wouldn't ripen properly and wouldn't be as potent. So thank you again mile that is awesome.
  9. Nice!!! Gonna cut out mine for the last two weeks now. Save me some propane and ripen up the babies!! Good find matty I'll definitely be cutting out CO2 in the ripening period.

    Happy Growing ~23

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