Cut off co2 before harvest

A question from a fellow grower:

does Co2 need to be tuned off a couple of weeks before harvest

Best to keep it “running” till you start to flush

Hope this helps,

Adding CO2 to the grow room does not directly increase yields. CO2 only increases the amount of energy your plants can produce under very high intensity light levels. If plants have not maxed out on light, adding more CO2 will not increase yields.
Another important point about using CO2 - In order for CO2 supplementation to be effective, you generally have to seal off the grow area and pump in enough CO2 to dramatically impact the CO2 PPM levels in the air. CO2 is dangerous to humans at these high levels, so be careful to protect yourself!
When you’ve reached the ultimate max of light that your plants can use, you still have a trick up your sleeve to further increase your yields. You can give your plants the ability to use even more of that light (and increase your bud yields even further) by increasing the CO2 levels in your grow room during the flowering stage.
So if light is like food for your plant, think of CO2 as a way to give your plants a way to “stretch their bellies” and eat even more food than would normally be possible.


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I don’t know if what I have been doing is actually having any benefit
at all but since I have a BAG of the EZ CO2 it’s basically a bag of
mushrooms that slowly releases co2 for 6 months.

Not sure if this helps but don’t think it could do any harm.

Anyway I have been using it in my closet grow so not a sealed environment
but my approach has been to turn off all fans, ventilation and close the closet
doors 3 hours before my 600w HPS comes on, once lights start I let them heat
up the closet for ten minutes at which time the temps are 80 to 84f. CO2 uptake
needs to be at 80+ deg if I am not mistaken. Of course I open closet and turn on
ventilation once the temp reaches 88 (only about 10 minutes) a day otherwise
temps are kept between 70 to 78f. Also have a digital laser heat reader that tells
me the leaf temps. I do have one hot spot about 3 sq. inches in size but if I keep
my lights at 12” from canopy that area never gets over 80 deg leaf temp

You very well may see the benefits. As I stated above.
But maybe not as much as you hoped for.
I to used though boxs but not any more. A fan does even better bring in freash air or cos