Can't lower humidity below 78%. Now what?

[nice fella]

So I'm growing in a 4x4 grow tent within a humid (but temperature controlled) basement. FWIW, it's also 90% humidity outside right now.

I ordered a recommended dehumidifier and ran it inside the tent, with passive air intake and the a 435cfm inline fan running for 24 hours. 78% humidity.

I then shut off the inline fan, kept the passive air intake vents open/dehu running and waited 24 hours. 78% humidity.

What can I do here? The basement is like 900 square feet so...just buy 10 more dehumidifiers? Move the grow upstairs? Will Co2 bags solve the problem? Thank you.

 

[Mr. J]

Ten more crappy ones or one good one. I wouldn't worry about it just yet. Hopefully the weather changes by the time your plants are finishing flowering. Don't listen to everyone and think you need to drop humidity into the 40's or else mold will ruin everything. If you have good air exchange and keep it under 65ish you'll be good, and that's for the last half of flowering.

 

[nice fella]

Thank you! I guess I'll stretch the budget and buy this in a few weeks:

https://www.amazon.com/Vremi-Energy-Dehumidifier-Spaces-Basements/dp/B07JMZJX4B

co2 scares me, plus with my temps in the 60's I doubt it would do much good anyway.

 

[Mattbho]

What are you lighting the 4x4 with? Like the above poster stated air flow is key especially 30-120 minutes after lights out .

Buds seem to dump water after lights out and you want that air outta tent asap

 

[OG_NoMan]

Personally I would be very worried. I just lost an entire crop due to PM from high humidity and temps out of control in my basement grow. With 90% humidity outside you are gonna have to run a sealed space with air conditioning and dehumidifier as well as fans for air movement. Good luck!

 

[troutman]

If the outside air is that humid you'll have problems if you're flowering.

You have perfect cloning conditions though. No dome required.

 

[wh1p3dm34t]

my friend used lot of rice as emergency dehumidifier

it will absorb lot of moisture, if you don t mind some waste or cook it as petfood or something

 

[troutman]

my friend used lot of rice as emergency dehumidifier

it will absorb lot of moisture, if you don t mind some waste or cook it as petfood or something

Maybe he can open a Ching Chong restaurant with all that rice.

 

[nice fella]

What are you lighting the 4x4 with? Like the above poster stated air flow is key especially 30-120 minutes after lights out .

Buds seem to dump water after lights out and you want that air outta tent asap

This is 78 percent humidity without the light even running yet.

I'll be running an LED light, specifically the Growers Choice ROI e680.

 

[nice fella]

Personally I would be very worried. I just lost an entire crop due to PM from high humidity and temps out of control in my basement grow. With 90% humidity outside you are gonna have to run a sealed space with air conditioning and dehumidifier as well as fans for air movement. Good luck!

Well, the heat pump (air conditioner) is in the basement and it leaks a little so I sorta have half-assed AC down there. Right now it's 66 degrees F.

I have a few small oscillating fans running in the tent.

I'm thinking keep the small dehu in the tent. Get a big ass fancy dehu for the rest of the basement, and open doors as needed for airflow as the grow progresses?

 

[Mr. J]

That's pretty cold. How's it in the tent? As the temperature goes up the relative humidity will go down but I don't know if that light you're using is going to raise temps enough to get good growth.

 

[nice fella]

That's pretty cold. How's it in the tent? As the temperature goes up the relative humidity will go down but I don't know if that light you're using is going to raise temps enough to get good growth.

Thanks. It reads 68F in the tent right now.

 

[OG_NoMan]

Well, the heat pump (air conditioner) is in the basement and it leaks a little so I sorta have half-assed AC down there. Right now it's 66 degrees F.

I have a few small oscillating fans running in the tent.

I'm thinking keep the small dehu in the tent. Get a big ass fancy dehu for the rest of the basement, and open doors as needed for airflow as the grow progresses?

IMO you are gonna have problems unless you can control your environment. I grow in a basement like you and shut down in the summer as it's too expensive for me to justify. Will flower a crop or 2 mid winter when temp and humidity is much easier to control for me. The crop I lost was due to flowering to late and getting an early summer where I live which I wasn't prepared for. I am not meaning to discourage you, just offering my experience. Wish you the best of luck

 

[Koondense]

Air conditioning(split) is your friend.

 

[Switcher56]

IMO you are gonna have problems unless you can control your environment. I grow in a basement like you and shut down in the summer as it's too expensive for me to justify. Will flower a crop or 2 mid winter when temp and humidity is much easier to control for me. The crop I lost was due to flowering to late and getting an early summer where I live which I wasn't prepared for. I am not meaning to discourage you, just offering my experience. Wish you the best of luck

... as I Nova Scotia here. I'm old. I don't have time to mess with growing during our summers here. I grow 2 crops per year (more than what I need) from the end of Aug until end of May

 

[indagroove]

I would run the dehuey outside of the tent instead. You're pulling air from the basement, so you want that air that's pulled in to be lower rh. If you keep the dehuey in the tent itself, you're just trying to lower humidity of the air while it passes through the tent.

 

[JKD]

Counter intuitive but in the meantime perhaps you could try raising your temps to between 80 and 90F to improve VPD and ensure enough airflow to prevent moisture settling on plants and add a filter for mold spores.

Not something I’ve tried btw
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[Mr. J]

Why's everyone do worried about the humidity when he says the temperature is 68? I mean, worry about the humidity but how are you going to grow anything at 68 degrees? Maybe I'm missing something. Cold, damp, dank basements are bad places to grow. Especially if it's an old house. Lots of fungi lurking, just waiting for something nice to eat.

 

[JKD]

https://www.icmag.com/ic/showthread.php?t=300255

thanks man..cloning tech posted above...im a firm believer in VPD, its a game changer in any room..i wont try to convince people on it, so please no one come in and try to tell me im crazy, as I assure you this is not my first rodeo...I run 84f and 75% rh through the whole grow, 70f- 74f and 65-70% at night...its hot and wet..glasses fog up when you enter...only the last week of flush will I drop it to 75f and 65rh ...during veg I run it even higher around 86-88 and 80%rh

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[Gry]

You are pulling some impressive responses. Would suggest send a pm to DHF over this.
I have a trashed immune system and am in the LA area, which is blessed with an abundance of mold and spores.
I did not have the money to put into AC and I was not able to shut down.
DHF was able to me come up with a means of dealing with it that was
affordable and passed muster with my landlord who used to run an AC
business and my wife who worked in public health.
Don't think he spends as much time on line as he once did, but he
will respond to a PM. Can not speak highly enough about the individual.