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The how to and why fors of CO2 supplementation for growers

*mistress*

Member
Veteran
Man a quantum light meter starts at about $200 (http://www.specmeters.com/Light_Meters/Quantum_Light_Meter.html) that measures PAR, gonna have to get one someday, but I'll still be one of only a couple guys here with them. Lumen meters are everywhere and cheap so thats what everyone uses for reference. Any estimates on how many PPFD a 1000W HPS puts out at 22" or so from the bulb?
cheapo, diy pyranometer meter (from other incarnations):
This is a gold mine of cannabis growing laboratory research
https://www.icmag.com/ic/showpost.php?p=2469835&postcount=7
quantum meter
measures the number of electromagnetic energy units (photons) available on the leaf surface in units of microeinsteins per square meter per second (ue/m^2/s).

radio meter
measures the amount of radiant energy available on the leaf surface in units of watts per square meter (w/m^2).

pyranometer
measures par (photosynthetically active radiation) watts/m^2.

measuring sunlight at earth's surface:build your own pyranometer:
http://www.pages.drexel.edu/~brooksdr/DRB_web_page/construction/pyranometer/pyranometer.htm
hope this helps. enjoy your garden!
 

Hydrosun

I love my life
Veteran
I made it through the first few pages and will have to come back to read the rest, but it looks like CO2 is my next step in upgrading.

peace, :joint:
 
I'm confused, can your room not drop below 1450 or is your burner circuit always live? Plants give off O2 at night and do not uptake almost anything, including CO2 so it's almost entirely wasted on them in the dark. I can post you some research papers on this if you'd like.

I've seen multiple sources stating what you said. Ed Rosenthal. The back of a CO2 controller box that had a timer that turns off the CO2 at night "because CO2 is not used at night".

I would really like to see those research paper on it, because that is not how I learned it in my college botany class in the eighties.

Photosynthesis is divided into two "reactions:" the light cycle and the dark cycle: photophosphoryation and the calvin-benson cycle. It is now known as the light cycle (because it requires light) and the light independent cycle (still the calvin-benson cycle) because it works in the light or the dark.

That's what I learned 20+ years ago. I understand that scientific "facts" often change. Can you enlighten me?

Thanks,

-L
 
G

grow nerd

Most seem to agree that flowering is about 5% faster with CO2.
I don't know about the entire length, seems to knock it down at least a couple of days, but what's really noticeable IME is the onset of flowers and how much more quickly they develop. IMO the biggest visible changes are from weeks 1-3.
 
G

grow nerd

I can't tell you much about the technical stuff on that, 'cuz I don't know it... but from what I understand CO2 is used for photosynthesis during light (CO2 + Mg + light, or some variation thereof?).

I've seen multiple sources stating what you said. Ed Rosenthal. The back of a CO2 controller box that had a timer that turns off the CO2 at night "because CO2 is not used at night".

I would really like to see those research paper on it, because that is not how I learned it in my college botany class in the eighties.

Photosynthesis is divided into two "reactions:" the light cycle and the dark cycle: photophosphoryation and the calvin-benson cycle. It is now known as the light cycle (because it requires light) and the light independent cycle (still the calvin-benson cycle) because it works in the light or the dark.

That's what I learned 20+ years ago. I understand that scientific "facts" often change. Can you enlighten me?
 
G

grow nerd

Really wish I could do side-by-side's and such more easily, like CO2 vs. no CO2, to see exactly what effect it has. For me running CO2 enrichment for increased production is only part of the reason, or rather a (huge plus) by-product of running a sealed & temperature/humidity-controllable environment. Not the other way around, kinda a chicken & egg ("which came first?") deal, though, I think :confused:... I mean it's really been a part of progressive upgrades through my career, and didn't have much desire to "get back to the basics". So I can't really say it does exactly this, or exactly that; hard to quantify at this point w/o doing side-by-side, is I guess what I'm trying to say. Just a big blurrrr.
 

Lazyman

Overkill is under-rated.
Veteran
Yeah it would be very hard to do a side by side for CO2. If they are in different buildings and you run the same water, strains, temps and nutes (no changes except for CO2) only then would it work. Whew that would suck!
 
Dear Lazyman,

I sure am trying to get this right, but maybe my efforts (and money) are being wasted.

I am blooming in a partially unfinished laundry room in the basement in a poorly built house.

It has a concrete floor, and I was able to drywall the room. I have an AC in the window well, and am cooling my lights with fresh air being pulled through the dryer duct through my lights and vented into the rest of the basement. This is relatively air tight.

My temperature is about 85-90 degrees.

My problem is that the room has no ceiling. The room was designed to be 8 ft tall. There is about 2 feet of dead space above this full of god knows what - random rafters (if it were a roof I guess), water pipes, and electrical, phone, and tv cables. Let's say a water pipe is 2 inches in diameter, the hole that goes into the subfloor is about 4 inches in diameter.

There are also random cracks and holes up there.

I do not have the skills nor the money to put in a ceiling, and I cannot physically fit into many of the spaces that I would have to reach to stuff the holes with insulation.

I am hoping that the CO2 is heavy enough to stay in the room and the plants are benefiting, but I have no idea. I am concerned that the temp is too high for the plants if the CO2 is wasted.

Do you have any suggestions for me?

Thanks,
-L
 

Lazyman

Overkill is under-rated.
Veteran
Hmm interesting. CO2 depends a bit on how it was dispersed. Hot CO2 from a gas-fired generator will cdertainly rise, but cold CO2 dumped from a tank will sink. Fans keep the whole thing mixed up though, or at least they should!

I had an unfinished ceiling in my basement as well, I covered the whole thing with sheets of Tekfoil insulation from Farmtek.com. Staples up easy and is flexible, tape the seams and joints with foil tape and you can make a pretty airtight pouch. It even comes with mylar on one side and white poly plastic on the other,m with two layers of bubble wrap inbetween. If that's not feasible I would at least see if you can borrow a CO2 setup from a friend for a day and run it, and see how fast it depletes or leaks. I tried it on my old grow and it leaked out faster than I could generate it! Good luck!
 
Looks like you have a drop (t-bar) ceiling minus the ceiling tiles. Would just 2x poly the whole thing. I would try using butyl tape or some other kind of adhesive to try and stick the poly to the t-bar.
 

hkush

Member
I've grown with and without added co2 and saw no difference whatsoever, except for loss of funds. Going to try again with a co2 meter someday.
 
P

puma

good reading but i need 1answer do you use CO2 in dark cycle or lights on..
thank you
 

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