High humitity and pm

[Hobocreations]

Hey guys. Been a regular reader and great advise on the forum. Thanks. 

 

I've read many things related already but could do with some help.

 

I have an issue that I'm really struggling with. I'm not new to the game and the more experienced I get the better my results. Unfortunately this is causing me issues. 

 

I have a grow space of about 2x3m 

4 600w mh lights (phillips)

8" Canfan q max on setting 2 with a 1 metre filter

Rvk150e2 inlet (getting decent negative pressure in room at this setting) ducting runs on floor with holes pierced to allow air flow under and up the plants.

1 oscillating fan on floor 

1 Gorilla fan above canopy.

Coco medium

20" airpots

 

5 week in flower

 

I've topped plants and have many top colas and 8 plants total.  It's a bit of a jungle and I know that I've not helped myself by topping and allowing them to grow big haha

 

With lights on I'm keeping a steady 25 degree's and withing 50's relative humidity 

As soon as light off my temps drop to 16degrees roughly but my humity spikes and stays up in late 70s to mid 80s. I tried a 30l dehumidifier last grow but still could only drop my humitity by about 10 maximum so still low 70s. 

My plants drink a lot and my ec an pH are accurate for stage in what I'm feeding, soil samples and run off. I keep a very close eye on all these things. 

 

I suffered pm on my last grow and luckily saved 70% of it all but this was in height of summer and my lights off temp was sitting at 22-24 degrees with 70% humitity. 

 

Will the dew point help greatly with the temp being lower now than in summer? 

So I'm considering a hotbox sulphur vaporiser. I'm reading conflicting things on taste etc. 

 

So please any suggestions to get my humidity down would be greatfull and and thoughts on sulphur at this stage in flower etc. I don't have any PM yet and all plants are thriving but it's a when you know you know. And I know I'm going to struggle soon if I don't tackle it quickly. 

 

Thanks for reading and any help will be greatly appreciated 

Peace 

 

 

 

 

[ratdog]

Just now, Hobocreations said:

As soon as light off my temps drop to 16degrees roughly

 

 

that's pretty low mate, your pots must be getting colder?

[Hobocreations]

Hey. Yes it is low. I put a heater in my room for lights off but all it done was spike my humitity . so took advice on not allowing the room to drop below 15 degrees. I have 3 Thermometers. 1 above the canopy 1 down low and one on wall. All read about the same so I know I have equal temp and humitity throughout but I'm guessing that's the airflow? I tried turning my inlet off when lights were off to see if that would help. I've tried so many things. Best result I've got was the dehumidifier but still that was only helping marginally. 

 

[ratdog]

i would get it up to 20 lights out and turn up the extraction

[Hobocreations]

Just now, ratdog said:

i would get it up to 20 lights out and turn up the extraction

Thanks. That's very easy to do and will get on it. But I still don't think it's going to drop my humitity but it will put the dew point higher. Not sure if I'm right but my understanding is I'm less likely to get PM if humitity is high but temp low versus high humitity and higher temps? Or am I wrong? Either way I'd rather the temp up but without the humidity rising also. 

As said I really appreciate all the help and advice. 

[MindSoup]

Where did you have you dehumidifier? I find it works best in the room you draw your air from rather than in the tent itself, get that "lung room" nice and warm and dry and the environment in the grow room becomes a lot more stable/ easy to manage. 

 

@ratdog IME without doing the above, ramping up the extraction will just pull more cold and damp air into the room making the problem worse. 

Edited December 31, 2021 by MindSoup

[ratdog]

where are you extracting to?

[Hobocreations]

Just now, MindSoup said:

Where did you have tou dehumidifier? I find it works best in the room you draw tour air from, get that "lung room" nice and warm and dry and the grow room becomes a lot more stable. 

 

@ratdog IME without doing the above, ramping up the extraction will just pull more cold and damp air into the room making the problem worse. 

It was in the actual room. I can put one outside and control that for sure. It would be close to my inlet though. Will that matter?

[MindSoup]

@Hobocreations No clue about the sulphur thing, I did look into Ozone at one point which would be a great idea if tour not an organic/no till grower.  

[Hobocreations]

Just now, ratdog said:

where are you extracting to?

Directly outside. Inlet from inside but I can draw from outside also if needed but as our humitity is in the 90s I don't see the point haha. 

[MindSoup]

Just now, Hobocreations said:

would be close to my inlet though. Will that matter?

 

Closer the better some people even tape their inlet duct to the dehumidifier itself

 

If you can run the dehumidifier off an humidity controller like an inkbird, with the sensor in the grow tent you'll be laughing. 

 

I had the same battle recently and thats how I solved it. 

 

E2A when you do it that way you can still have your fans turned right down to save on heating costs.

Edited December 31, 2021 by MindSoup

[Hobocreations]

Just now, ratdog said:

where are you extracting to?

 

Just now, MindSoup said:

 

Closer the better some people even tape their inlet duct to the dehumidifier itself

 

If you can run the dehumidifier off an humidity controller like an inkbird, with the sensor in the grow tent you'll be laughing. 

Will look into this. Thak you. I hired the dehumidifier last time and as it didn't drop much I didn't see the point in investing. I'm thinking about getting a 50l per day one and look into inkbird. Cheers

[MindSoup]

Go for it mate, I'm confident it will solve your issues. Get one off scamazon, make sure its sold directly by them, be out/don't answer the door when it arrives and tell them it never turned up . That's obviously totally hypothetical advice that I would never do myself or anything, especially not more than a couple of times on one account.

Edited December 31, 2021 by MindSoup

[ratdog]

Just now, Hobocreations said:

Directly outside. Inlet from inside but I can draw from outside also if needed but as our humitity is in the 90s I don't see the point haha. 

 

 

where are you?

 

that's insane, i'm spending all my efforts to get my humidity up to 70 and i'm in a cold damp flat, infact i get mold if i don't have the tents/fans running regularly

[MindSoup]

@ratdog you lucky b*stard.