CO2 Production, Any chemists out there? (Newbie Question)

Discussion in 'Growing Marijuana Indoors' started by SweeneyWeeney, Nov 21, 2014.

  1. Ok so I'm going to begin by stating that I have yet to grow a single plant, nor have I even began my project on building a growbox for my closet. While doing my research and reading the stickies I came across someone mentioning putting yeast in their growbox to increase the amount of CO2 in the environment(maybe to make the need for a fan obsolete?). As many of you probably know the photosynthesis requires three things, H20, CO2, and the catalyst of sunlight in order to produce Carbohydrates needed for growth. This struck me as a possible way to make the need for a fan and carbon filter obsolete, at least for micro grows. So could I possibly use dry ice and water, or the mentioned yeast to produce CO2? or is the fan needed also to filter out already produced oxygen in which the plant doesn't need. And my last question is rather complicated and I don't expect to be answered but how many moles of CO2 can be consumed by photosynthesis and to what relevant size of plant? Sorry, taking a chemistry class and envisioning my first grow is just a bad combination lol  :smoke:

  2. The fan and filter has zero to do with filtering out uneeded oxygen. Fan is to supply fresh air flow, filter is to scrub smells. Plants do use oxygen. If the roots aren't getting enough oxygen your done.
  3. So would the oxygen it generates through photosynthesis be enough to supply for the roots, or is a fan needed in that case. Carbon filters are like one of the most expensive parts of the setup and I'm broke as is... Ahahah
    Sent from my iPhone using Grasscity Forum
  4. Cause I mean if you had an air tight container the plant would turn all the CO2 into Oxygen right? So aren't fans needed to get fresh airflow which has more CO2?

    Sent from my iPhone using Grasscity Forum
  5. #5 Grade A, Nov 21, 2014
    Last edited by a moderator: Nov 21, 2014
    Fans help circulate the air and strengthen the plants stems

    Stagnant air is no goos
  6. #6 Snake Chamber, Nov 21, 2014
    Last edited by a moderator: Nov 21, 2014
    Alot of the oxygen the roots need is supplied by h2o. For a small grow I don't reckon you would benefit much from higher carbon levels in the air (maybe I'm wrong).

    If you're worried about the smell and don't want to spend the money on carbon filtering, you could try a low odor strain or the cheaper options such as the gel (not sure what its called but it removes odors from the air). Or you could try making a home made carbon filter (there are a few threads and videos around showing how to makr them for under $20)
  7. You will need a fan of some sort no matter what. Most likely you will need one fan to extract all the hot air from your grow space and another to circulate air(depending the size of your growspace). I have a small box 16x16x18 that I am using for seedlings. That box can get in excess of 90 with one cfl if I do not extract the hot air. Regarding all the Co2 stuff, I wouldnt bother on your first grow. There is plenty to learn within your first few grows without adding more to the equation.
    Best of luck though man
    What size box you thinking of building?
  8. If you're on a small budget and first grow, I don't think CO2 should even be considered.
    Try and learn how to properly grow your plants first, then you can think of adding CO2 and other optional stuff to squeeze out every bit of quality and quantity you can.
    Because if you screw up some basic stuff, CO2 won't make any difference and you will only have wasted time and money.
    Venting will be essential if you don't want to cook your plants, even with added CO2, from what I've read, CO2 will help the plant endure higher températures, but you will still need to control it so you don't get too hot.
    You don't want to spend money on a filter? Have you thought of venting directly outside and let the Wind carry the smell away?  If you only have a small grow venting out of a 2nd story window will be enough to save you from the smell. You can always get some ONA gel or liquid to help you control the odour but it will not remove it completely like a good carbon filter. DIY filters will help but in my experience the 150$ you will spend on a good fan and filter is Worth it!!!
    I have been growing for about 2 years, done hundreds of hours in reading and educating myself on how to properly grow my plants and invested a good 1000$ (LED isn't cheap ;)  )  and I still consider myself a Novice and I still have lots of experience to earn.  But the amount of money I've saved by not buying weed on the Streets and the quality I have gotten out of my plants are Worth every penny and minute I've invested doing it.  And frankly, there's nothing like having a 20+ years smoker come to you and tell you your weed was one of the best he's ever tasted.
    In my experience, every penny you save by cutting corners will cost you twice as much in the long run.
  9. #9 howando, Nov 21, 2014
    Last edited by a moderator: Nov 21, 2014
    How many moles of carbon dioxide?  Huh, okay
    Let's say that you grow a plant that yields 1 oz of dried bud, lets assume that it's maybe 30% water mass so 20g of actual organic product.  If we assume the general formula for the organic matter is C2H4O2N which has a formula mass of 58 g/mol.  That means we have something like 0.34 moles of that formula, that's 0.68 moles of carbon.  One mole of CO2 has 1 mole of carbon, so that's about 30g of carbon dioxide required just for the bud to harvested.  Stems, roots, leaves, all need carbon too so lets double it at least and call it 60g of carbon dioxide.
    If that was pure CO2 gas, you'd need a 5 gallon space with pure CO2 at rtp, or because the composition of the air is only 0.04% CO2 then you'd need 12500 gallons of air to contain enough carbon, or around 2000 cubic feet of air, for one plant yielding 1 oz.
    The problem with doing this in one box is, once your grow is half way through.... the concentration of CO2 is now low so you have restricted growth, it has all been used up.  You have a high concentration of oxygen, which is a very powerful oxidizing agent.  You also can't add or remove any water through the whole grow, so either your plants have been in soaking wet soil (so no oxygen getting to the roots anyway, they like to be dried out regularly or they rot) or you have a bone-dry plant when it uses more water than you planned.
    Plus any bacteria in the soil will enjoy the anaerobic environment at the start, bugs and mould will be free to run rampant, humidity will be a problem because it will get high and you can't control it in a sealed box
  10. thanks bud! Very helpful! But I only have like a 2.5x6.5x 7 space for space(my closet). So what I'm thinking is either building an enclosure or buying a tent. I'm a crafty kid an know I could get more out of building it. Plus I could have one environment for veg in a 2x3x5 space and another for flowering. Both will be on different time schedules and lighting because I don't plan on doing autos. Any suggestions on where to buy lights for cheap? And material for insulation and/or distributing light correctly?

    Sent from my iPhone using Grasscity Forum
  11. that makes sense, I didn't even think about them getting water from h2o! Thanks man. I'll definetely look into DIY filters.

    Sent from my iPhone using Grasscity Forum
  12. Thanks bud! Very good advice. My house is actually really cold. Like my dad doesn't turn on the Heater, so it's constantly 65< with a low of like 50 in my house. But as far as ventilation goes do I need to have a fan that blows fresh air into the box? Or is that the partial purpose of the filter? Venting directly out if my house is almost out if question, I have no opening to my attic and exhausting it out my window would not only be obvious, but smack every little kid in the face with it's wonderful aroma. Lol not a good idea for me.

    Sent from my iPhone using Grasscity Forum
  13. Wow. 👏 lmao I'm surprised that anyone put that much effort into that question. And a very crazy way looking at it when you think the air is only .04% so putting that high of a concentration of CO2 would be illogical for natural circumstances. Isn't 24 hours of light illogical too? Lol but yea the bug, bacterial, and fungal risk would be bad. Heat and Moisture are a bad idea. Thanks bud!

    Sent from my iPhone using Grasscity Forum
  14. I have a chemistry PhD so it took like 2 minutes :D  Believe it or not, it was kinda fun to work this out.
    24h light is unnatural, and some people believe that dark-time encourages healthy root development, but I'm not sure.  I have heard that automatic plants get stressed by 24h light and need to have a dark period, but regular cannabis is literally like a weed.  it will grow and grow and grow as much and as long as it can, and then when it sees that the days are getting shorter and it doesn't have long until winter it starts to flower.  So even though it is unnatural to have 24h of light, they don't actually require 'sleep' like animals do.  We need to rest our brains and muscles, plants do not and they can just go and go.
    However there are always some plants that require night for some reason, either they only flower at night or are pollinated at night or something like that, and those plants wont like 24h daylight.  Cannabis doesn't mind though, it likes it.
    A few millions years ago, when dinosaurs were massive, the concentration of CO2 in the atmosphere was much much higher than today, and because of that the plants grew much much bigger as well.  It is well known that increasing CO2 concentration increases plant growth, however the amount you need to increase the levels by is like 20x and you have to maintain those levels which you can't do in a cupboard, otherwise it's not effective.
    Air circulation is very very helpful.  You do need to at least open your grow space every day and let the air move.  You can use a carbon filter with an inline fan to draw air out of your space, that will stop the room getting stagnant, and because it is filtered there is no smell so you can just vent it straight into the room/attic/where ever.  Having a desk fan actually blow moving air over the plants is also useful because it reduces the chance of water condensing on the leaves and mould developing on the buds, it helps to strengthen the plant stems too.
    Don't get me wrong, you can just put them in a cupboard and open the door for an hour every day, that's it you don't need fans or whatever and that's fine but it will smell of weed.
    You can get a tent kit from eBay, there are lots of different sizes available to look around.  If you build your own, either get proper mylar sheets or paint the walls flat plain white.  Don't use foil or emergency blankets or mirrors or any of that.  Mylar, white, or just don't bother doing anything about it.  There are lots of light kits too, think about 50+ watts per sq foot so maybe 1x 600w or 2x 400w lamps if you use your whole cupboard space
  15. Guess that opens up some possibilities for my future grows. Maybe I should make both the containers Equal so that I could compare the differences between Co2 Supplemented plants and non-Supplemented. Imagine what monstrous/prehistoric yields you could get just by changing the environment! Lol But on a serious note, should I worry about size of the container and how powerful of lights? I don't want the little amount of space to overheat too quick, so if I were to have two 2x3x6 containers, one split in half for veg stages, and one full size for flowering or late veg stage, what would you suggest for each? and do you have any idea where to get good seeds from? Any suggestion on a good strain of indica for anxiety that has high yield?
    If you have one space that you are going to split between veg and flowering, you must must must ensure that the flowering area is light-proof against the veg space next to it.  If light from your veg space leaks in to your flowering room, they wont flower well.
    The 50ish watts per sq foot rule of thumb still applies.  In your 2'x3' space something like 250w MH would make a good space for new plants and clones, and 400w MH would fill that space for strong veg, or HPS flowering.  Depending on your ventilation and ambient temperatures where you live, 400w might be too hot in that space without stuff to manage it.  I am in the UK entering late autumn, and I have a 2'x2'x4.5' tent with 250w hps and it just about gets away without needing a fan so that I don't have to bother setting one up.  Three months ago I would definitely have had to sort it out though. I think if I had 400w in that tent, I would want maybe an air-cooled reflector or it would get too hot.
    Seeds wise, I grew a sensi northern lights and it was chunky as hell, that's the best I've grown yet in terms of yield.  If you want medication though, do look for something that is for it.  I tried a CBD Crew plant, Nordle, and although it wasn't very recreational, I wasn't very high or stoned, I did feel satisfied by smoking it and it did cut at the anxiety pretty nicely.  I was smoking it all day and getting on with everything pretty normally.
  17. I'm going to build the two enclosures separately so they'll be no chance at light seeping through into the enclosure for flowering. And what about size of the container? I heard a gallon a foot? But I'm not sure if that is veg or flower stage they were referring to Ahahaha
    Sent from my iPhone using Grasscity Forum
    Did you mean a gallon per foot of height?  Actually that sounds like a pretty reasonable rule of thumb, but maybe slightly larger pots where possible.
  19. Yea while I was reading the stckies one guy had mentioned that for each gallon of space you have the plant in, you could expect about a foot large plant. But is that for veg or flowering growth, because he very broadly said "you could expect three times that" in a later comment, so I was a tad confused. And would you suggest growing organic or hydro? Im trying to work out every last detail beforehand if you could tell. too anxious lol

Share This Page