Got into this thread late. Sorry to hear about your situation, bud rot is the worst, been there, done that.
I'd like to start off by saying that you have a beautiful plant. That being said you obviously have a green thumb. At the same time I think there are some concerns that I'd like to point out.
I'm too tired to read all the posts and I'm sure some people will agree and some will disagree but here's what I think anyway based on my experiences.
1. Fabric pots are not good IMO. I've used them before and they stay wet, too wet. Anything that stays wet in your grow area is bad.
2. I saw you're using up to 50% perlite in your medium. That's too much. You want about 10% to 15% when you mix with a medium. This is where some people may disagree but I know for a fact, based on experience, that too much perlite mixed with a medium keeps the medium wet for too long because perlite is porous and it helps the medium retain water. If you have 100% perlite then it will drain, but once again, if you mix your perlite with a medium and you have too much perlite, it keeps the medium wet for too long.
3. I only see one small fan in the pics. I think you need a lot more air flow. For example, I have a 3x3 tent and have three fans on all the time during flowering. One is a big oscillating fan and then I have two smaller fans that constantly breeze the canopy. Airflow is your friend and it's good to have lots of friends.
4. Is there and intake of fresh air in your grow area? I see some ducting above in the pics but it doesn't look like you have any fresh air coming in. If you don't you need some.
5. RH goes up with cooler temps, but sometimes an air conditioner conditions the air to an extent that it will lower the humidity and sometimes it doesn't. When my humidity is going up I start with running the a/c. If it doesn't help I'll switch gears and try the other side of the coin and use a heater in the room. Sometimes the dry heat helps. Controlling humidity can be an art and a science. What works sometimes doesn't work at other times since there are so many factors. It can be warm and rainy outside, cold and rainy outside, hot and humid outside, etc. This is where you have to experiment with what works best at that time and place.
Good luck.
Thanks for stopping by and for your tips, i am a new grower so tips and tricks are always welcome, although i have been in friends grow rooms before, they do not know that i have started a grow and i want to keep it that way so i can't ask them for advice.
1. I got the fabric pot on a recommendation from the guy in the hydro shop i use, he said they were good for first timers. I haven't noticed it becoming saturated since the plant got bigger and filled it with roots although i will keep a closer eye out for that.
2. I didn't know that perlite helped to retain moisture, i thought it was good for aeration of the medium but it seemed to work quite well for me as i only water by hand once every 2-3 days in veg and every day in later flowering.
3. I did only have 1 small fan blowing over the canopy and i think that may well have contributed to me getting the grey mould, i have now added a second fan and she is moving quite a lot in the wind now
4. The ducting is purely for the cool tube, i like to get the light close so i need it cooled.
I have a 4" intake fan and a 5" exhaust (through an external carbon scrubber), they are controlled by a SMSCOM twin fan controller although with the cooler night time temps it was running too slow and prob not venting the room effectively, this has now been tweaked for better ventilation.
5. I live in the UK so aircon is not something we have lying around. Having said that i do have a portable aircon unit but if i put that in my cupboard there wouldn't be any room for my plant
This is a stealth grow in a 37" x 28" x 72" cupboard and space is at a premium.
Since adding the small heater the humidity has dropped so i am hopeful that i can keep the mould down to a minimum until i can harvest.