Higher temp at night?

Helmut79

Helmut79

Well-Known Member
When it's moist outside, I'm having a problem with RH indoors, but I don't have money for a dehumidifier at the moment, so I'm considering one possible solution - to increase temperature to reduce RH.

I'm thinking about increasing it from 66F (19C) to 77F (25C) for example. Do you see anything wrong with this idea? How much is too much at night?

Plants are flowering by the way.
 
Helmut79

Helmut79

Well-Known Member
If it's dry outside, then inside it's about 45%, but if it's moist outside, it can get as high as 65% which could make it mold.
 
GreenSanta

GreenSanta

Well-Known Member
Increase airflow, sure helps preventing mold. U could have another set of intake / exhaust fan on timers so that you could use fresh air from inside your house at lights off. I grow with LEDS so I run intake exhaust fans 24-7 with air from inside my house, exhaust in the basement.
 
Roger A. Shrubber

Roger A. Shrubber

Well-Known Member
add a little air flow as well, not a howling gale but make sure air keeps moving. 65% rh isn't that bad, if it goes over 70 i'd start keepin a sharp eye on things.
this is pretty ghetto, but you could freeze gallon jugs and sit them in saucers around the room, a lot of the water in the air will collect in the saucers, you just have to remember to empty them and refeeze your jugs
 
GreenSanta

GreenSanta

Well-Known Member
40%-50% should keep u in the clear for mold, that s what I shoot for for both veg and flower. Anything above 55% when u have big colas u should be worried.
 
Helmut79

Helmut79

Well-Known Member
GreenSanta said:
Increase airflow, sure helps preventing mold. U could have another set of intake / exhaust fan on timers so that you could use fresh air from inside your house at lights off. I grow with LEDS so I run intake exhaust fans 24-7 with air from inside my house, exhaust in the basement.
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Increasing airflow only increases RH. Because it's coming from outside where it's moist.

Heating always reduces RH. That's why I'm asking about heating it up to 77F and if it's okay for the plants to have that kind of temperature at night (same as when lights are on).
 
Roger A. Shrubber

Roger A. Shrubber

Well-Known Member
i don't think its a good idea to increase temps without increasing airflow, w/e its coming from. increasing temps without giving the moisture a chance to be carried away is just making a big incubator.

its better if they have at least a ten degree difference between day and night temps, but if mold is that big of a concern, i guess it would be more important to avoid the mold.

i think i'd just pick a better place to grow next time, or go mow a few lawns and buy a small dehumidifier
 
evergreengardener

evergreengardener

Well-Known Member
If you have the space in your room a bucket full of rice can be had for like 10 dollars and if you set it in the room it will bring down the rh some as it will absorb some water from the air (for a quick short term fix)
 
Cyrus420

Cyrus420

Well-Known Member
My humidity went as high as 70% during my second grow mold was not an issue at all. It was only during lights off ever since I added an inline fan I can't keep the RH above 45% no matter what. No my preference for vegging but it's golden when flowering time comes along.
 
I

Illinois Enema Bandit

Well-Known Member
Helmut79 said:
Increasing airflow only increases RH. Because it's coming from outside where it's moist.

Heating always reduces RH. That's why I'm asking about heating it up to 77F and if it's okay for the plants to have that kind of temperature at night (same as when lights are on).
Click to expand...
If you plan in increasing temps using the buildings HVAC system the increased heat shouldn't create more humidity due to the HVAC removing RH as it raises the temps ,that would be a good plan as having a constant temp 24 hours a day won't slow down budding .

However if you plan on allowing temps to increase by passive means as in shutting down airflow,or allowing room temps to use the earths heat to raise temps,you'll only increase the humidity levels and create a more uncomfortable environment for the plants .
 
Big_Lou

Big_Lou

Well-Known Member
Illinois Enema Bandit said:
If you plan in increasing temps using the buildings HVAC system the increased heat shouldn't create more humidity due to the HVAC removing RH as it raises the temps ,that would be a good plan as having a constant temp 24 hours a day won't slow down budding .

However if you plan on allowing temps to increase by passive means as in shutting down airflow,or allowing room temps to use the earths heat to raise temps,you'll only increase the humidity levels and create a more uncomfortable environment for the plants .
Click to expand...
I heard that nazis grow terrible weed. Dunno if it's TRUE, but I've been hearing things....people are saying...
 
W

Woodfella

Member
Slight hijack... I'm using the GE 50 pint dehumidifier for 224 sq ft of total ventilated area. Slow fresh air in and a little faster out. It's in the room. The exhaust is piped into the filter to keep heat down. Temps are 79-67 and RH is 65%. I CANNOT get the RH any lowwer for the life of me. I've considered extreme defoliation to help with transpiration.
Discuss?
 
I

Illinois Enema Bandit

Well-Known Member
Woodfella said:
Slight hijack... I'm using the GE 50 pint dehumidifier for 224 sq ft of total ventilated area. Slow fresh air in and a little faster out. It's in the room. The exhaust is piped into the filter to keep heat down. Temps are 79-67 and RH is 65%. I CANNOT get the RH any lowwer for the life of me. I've considered extreme defoliation to help with transpiration.
Discuss?
Click to expand...
Start a thread titled " Help with humidity issues " and many experienced growers will help you over the course of 24 hours .

Explain your grow method,room conditions,exactly how air intake & exhaust are applied,also explain in depth how the dehumidifier exhausts into a filter & where the filtered heat goes,don't forget to include daytime & night time temps & RH.

You'll get more views & a lot more help starting a dedicated thread, members entering the thread knowing the question are more apt to offer detailed advice,plus your issue isn't just a quick response & will require a complete thread derailing to answer .

Gkkd luck .
 
Helmut79

Helmut79

Well-Known Member
Firstly, I can't understand why are you guys talking about reducing airflow? I was not talking about that. I was talking about increasing temperature by heating more. Heating reduces RH.

Airflow would be the same - 0.4 air exchanges per minute. Simple logics is that if I increase ventilation speed, then it will suck in moist air from outside faster and I would need to do more work to reduce RH. It's usually 60-90% outside where I live.

The intake is in the heating room where cold temperature is allowed to enter passively from outside to heat it up to a range of temp that is good for the plants (it's almost freezing outside). Then it moves into growroom from there to be sucked out by an extractor fan.

So there's that. If I increase airflow, then I would be just wasting money to keep up with the heating. If I keep airflow the same, but increase temperature, the result should be reduced RH.

That incubator thing one guy were talking about didn't make any sense to me.
 
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Helmut79

Helmut79

Well-Known Member
Illinois Enema Bandit said:
If you plan in increasing temps using the buildings HVAC system the increased heat shouldn't create more humidity due to the HVAC removing RH as it raises the temps ,that would be a good plan as having a constant temp 24 hours a day won't slow down budding .
Click to expand...
That's what I was talking about. The impact of constant 77F temperature. Does it harm the plants any way besides that I would probably need to water them more often?

Although not sure what's HVAC. I'm using an automated wood pellet heating system.
 
SPLFreak808

SPLFreak808

Well-Known Member
Dont think it will make much difference since mold preferes higher temps where the air can actually hold more water.

For the most part, oscillating fans coupled with a dehu or purifier seem to work well for sealed room/high rh growers without bud rot problems.
 
I

Illinois Enema Bandit

Well-Known Member
Helmut79 said:
Firstly, I can't understand why are you guys talking about reducing airflow? I was not talking about that. I was talking about increasing temperature by heating more. Heating reduces RH.

Airflow would be the same - 0.4 air exchanges per minute. Simple logics is that if I increase ventilation speed, then it will suck in moist air from outside faster and I would need to do more work to reduce RH. It's usually 60-90% outside where I live.

The intake is in the heating room where cold temperature is allowed to enter passively from outside to heat it up to a range of temp that is good for the plants (it's almost freezing outside). Then it moves into growroom from there to be sucked out by an extractor fan.

So there's that. If I increase airflow, then I would be just wasting money to keep up with the heating. If I keep airflow the same, but increase temperature, the result should be reduced RH.

That incubator thing one guy were talking about didn't make any sense to me.
Click to expand...
lol chill out bro,nobody is attacking you,we asked about air flow for a reason,not to try n fuck with you,you weren't clear how you wanted to raise room temps,in some states its still hot outside & I wasn't sure weather you were talking about raising temps via allowing room to reach outdoor temps,or as you've now explained using mechanical heating aka HVAC .
 
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