Lighting is the chief cause, followed by bad genetics. Not having any idea of your setup it’s frankly impossible to provide any insight.
Also; unless running double the amount of light needed to properly flower off a plant, you are wasting your time running any CO2. Plus, fermentation or ‘exhale’ bags are a complete waste of money. You need to be in a closed-loop, highly controlled environment with light levels around 1,500 µmol/j/m2 to utilize it.
Just putting this out there but I personally do not want rock hard nuggets. I don’t want larfy wimp-ass buds either but there’s a wide range of happy medium in between those extremes.
A million years ago one of the really common buds you’d get would be Beester - usually M39 - and the nuggets were hard as a rock.
I still think of the desire for really dense hard ass buds to be something that’s only important for cash croppers. As a guy just trying to grow the best damn smoke he can get I can say I worry a lot less about how dense my buds are and a lot more about how it tastes and smells and how faded it gets me
You’ll see benefits if you enrich CO2 above atmospheric levels even if your light levels are below 1,000 µmol/j/m2, but yes, the concept of a sealed room escapes most people. Unless you’re sealing the CO2 in, you’re wasting money. And sealed spaces present other challenges.
For most growers, the best way to ensure adequate CO2 is to bring fresh air into the room.
Your problem is light lights light and more light.
You really can’t buy bargain basement bulbs to produce premium bud.
The biggest obstacle to growing in the 80’s and 90’s was the electrical bill cost for the lighting.
Now that LED’s are half decent they sell everyone on this dream that all LEDs are similar.
They couldn’t be more wrong.
Growing budget for grow tent:
50%-60% of your budget needs to be on LIGHTS alone.
20% Soil pots, nutes, special amendments
20% Tent and exhaust,
Another reason I am not a fan of autos. New growers pick them thinking they might be easier to grow. Nothing could be further from the truth. Some people love growing them, but they’re just not my thing. This is only opinion, of course.
I think your onto something. I usually de-bulk them then hang upside down in a dark closet for about three days. They are usually fairly dry to the touch. I then nug them out and jar up the nugs into mason jars with a 62% dehumidifier packet. I burp and shake them once a day and sometimes I will put plastic down and dump everything out and aerate them for about 30 minutes before returning them to jars.
So the question remains why do they dry light and fluffy, because let me tell you I have already tried some and its Fire! I was wasted for hours.