does the drying cannabis actually need an air exchange (fresh air or co2) or is it really just about keeping the temp and rh where you want?
You will have to exchange some air to remove moisture as the pot dries unless it's managing to keep the rh down thru leakage to the drier air which is basically a passive air exchange.
Here's a post about how I slo-dry my pot I saved for an occasion just like this.
When time to crop I only take enough of the larger ripe colas that I can trim up in an hour then go back for more. After a couple of hours the little bud leaves go all limp and that makes it harder to snip them out as I do my final trim and breakup of the colas fresh off the plants. I'll get all the riper, main colas off then let the lower ones go another week to 10 days before finishing off the plants.
Once I have a big pile of trimmed buds I double up some paper bags like the lunch bags you can by at the grocery store and put them in there folding the tops over and putting a clip on to hold it shut. I keep them down in my cool basement so they dry very slowly. For the first few days I'll dump them out into a big tray and carefully break up any clumps and let them air-dry for 15 min or more then put them back in the bags. After that few days I'll just open the bags and shake them around a bit and wave the bag back and forth a bit to exchange the air in there and let some moisture out. Takes about 3 weeks before they are dry enough to put in jars but still moist so daily burping is needed and some shaking to break up the big clump. Mold is a distinct possibility so you have to keep an eye on things. If you don't have a cool space then you need to open and air-dry more often. It's only 50F down there right now so that's just right for me. Never gets over 65F down there but I consider that warm for curing. Could do it in a fridge too but note that it will stink everything up so the spousal unit may object.
That's it in a nutshell. For the sugar trim and popcorn pile I just use one bag and the same procedure but they are real dry in a week or so then just go into a jar for storage until I get around to dry sifting them for kief and/or making oil from it.
