Fans on 24/7 or off during dark period?

kmin

kmin

Member
Hello everyone. Title says it all. It's a simple question that i couldnt find an answer on.

Right now I have both my exhaust fan and regular air moving fan on my timer along with my lights. When lights go out everything goes out.

Should the exhaust fan be on even during lights out? Does it matter?
 
spitsbuds

spitsbuds

Well-Known Member
yes. im run vents 24/7 especially in late flowing. once they hit the dark in veg i run mine 20 mins of every hour. but thats me and may have no bearing on youre set up. you might have to run them longer or shorter all the time. i just found 20 mins is the shortest i can go. but once they hit flowering its never of
 
kmin

kmin

Member
Grumpy' said:
Do your plants stop breathing when it's lights out?
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No, I suppose not. But I'm venting for heat issues not for air issues. I never really gave it thought. I just assumed they got enough air passively from the exhaust/intake during lights off.
 
tip top toker

tip top toker

Well-Known Member
The exhaust fans are exchanging the old air with fresh air. Quite an important thing. consider it like breathing nomally, or putting a bag over your mouth and trying to exist on the air within that alone. You can't. Certainly not quite as extreme, but the same principal.
 
golddog

golddog

Well-Known Member
I run my exhaust/Carbon Scrubber 24/7 - to keep the smell down.

I run my circulating fans when the lights are on.

Hope this helps :joint::peace:
 
kmin

kmin

Member
Thanks alot for the replies everyone!
My grow has been going for some time now with the fans being off whenever the lights go out. I just never gave it any thought until now.
It really is common sense I suppose. Thanks again, I'll go adjust my setup now.
 
spitsbuds

spitsbuds

Well-Known Member
so if youre venting only for heat. how are you exchanging you're air. its just not about blwoing the air in there round with a oc fan. you need to exchange for them gasses. stop stale air gathering round leafs ect ect ect ect ect ect ect
 
Slipon

Slipon

Well-Known Member
I runn my exhaust ventilation (carbon filter) 24/7 boath for fresh air and odour controle ..

I also runn a tower fan in ther .. on the floor .. to spread the air around .. I also runn that 24/7

then I also runn a big "normal" table fan .. pointet at my 600W HPS (a foot away or so) .. that is on a timer .. I make it start ½ a hour before lights and let it runn a hour after to cool it down ..

works for me ..
 
kmin

kmin

Member
You're all awesome! Thanks for all the replies. if i could +rep you all I would.
At one point there were 11 views and 9 replies. now that's what i call definitive!
 
kanx

kanx

Active Member
Keep your fans on, the only fan you can safly turn off is the intake fan when lights go off to stop it getting to cold.

If you turn your outtake off when the lights go off you run the risk of possible mold , as when the lights go off your humidity goes up, since theres no heat from lights.
 
spitsbuds

spitsbuds

Well-Known Member
kmin said:
You're all awesome! Thanks for all the replies. if i could +rep you all I would.
At one point there were 11 views and 9 replies. now that's what i call definitive!
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ye i like it here at riu. i learnt so much from the growers here. but remember it works best when you put up a honest q with info(like u did) not something u could find the answer you if you just used the search bar at the top right. also remember if you do this you will get good solid awnsers to. you just have to take in account. that even if the info might seem contradictive. just keep in mind different grow styles. set ups methods. strains. will determine the growers answers. just have to take what applies to you also ignore the ones who just put up crap. u can spot them quite easy
 
TheMadScientist99

TheMadScientist99

Member
Plants do not breath at night, as no photosynthesis takes place which is the only time it needs CO2. However fans will help reduce the presence of mold and algae while creating stress on the plant causing the stem to grow bigger. Bigger stems typically means shorter, sturdier plants which means more nutrients can be brought up from the roots to the bud. Shorter plants are preferable due to the increased amount of nutrients and water which can be brought up to the buds. Soil does need to "breath" oxygen however moving air is not necessary to do so.
 
tip top toker

tip top toker

Well-Known Member
TheMadScientist99 said:
Plants do not breath at night, as no photosynthesis takes place which is the only time it needs CO2. However fans will help reduce the presence of mold and algae while creating stress on the plant causing the stem to grow bigger. Bigger stems typically means shorter, sturdier plants which means more nutrients can be brought up from the roots to the bud. Shorter plants are preferable due to the increased amount of nutrients and water which can be brought up to the buds. Soil does need to "breath" oxygen however moving air is not necessary to do so.
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Respiration takes place 24/7.
 
Grumpy'

Grumpy'

Active Member
TheMadScientist99 said:
Plants do not breath at night, as no photosynthesis takes place which is the only time it needs CO2. However fans will help reduce the presence of mold and algae while creating stress on the plant causing the stem to grow bigger. Bigger stems typically means shorter, sturdier plants which means more nutrients can be brought up from the roots to the bud. Shorter plants are preferable due to the increased amount of nutrients and water which can be brought up to the buds. Soil does need to "breath" oxygen however moving air is not necessary to do so.
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Back to researching for you. Plants take in co2 during daylight hours and produce o2. During night hours, it reversed. This is why you run co2 during your day period.
 
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