Exhaust fan off at night?

J

jimmyblack420

Member
Hey guys,

Quick question about the ventilation at night in my tent.

Its a small 80cm x 80cm x 180cm tent and I only have 1 seedling in there at the moment under an LED waiting to sprout.

My question is at night time the ambient temperature sits around 21c-24c (70f-75f), so would it be ok for me to leave the extraction fan off for the 6 hours that the light is off? (6" oscillating fan will be on and passive intakes will still be open)

Maybe have it on for 10 minutes every hour or something?

If this is ok, would it be ok to do this for the first 3 weeks or so while there is no smell coming from the plant?

The noise of the extractor fan can be slightly annoying while trying to sleep right next to it so would be nice if i could turn it off during the dark period and knowing my plant will be fine. (Ill have it on a timer to come back on in the morning)

All all help/advice would be appreciated.

Thanks!
 
researching

researching

Well-Known Member
Only reasons to run it are... temp control, smell control, movement of air/fresh air. As long as those are in check without having to use the fan then no need to use the fan all the time. I don't run my fan until flowers and smell appear. That being said that will depend your living/growing situation and where you are located.
 
J

jimmyblack420

Member
posterart

posterart

Member
By shut off your fans ...do you mean intake and exhaust fan or do you mean oscillating fans in the room ??? I keep my exhaust on 24 /7 . It`s a good question , I would like to save money during peak CA rates . I think a low circulation during dark period is good , and vigorous oscillating when lights are on
 
K

Kili Frunza

Active Member
You can run it at night for temperature control and smell control, also be sure to have a hygrometer to see the humidity in the growroom. When plants sleep they sweat (A LOT), if the humidity gets over 40% while in flowering then you are risking mold, so you should let it run to get that humidity out!
 
posterart

posterart

Member
Kili , Hey buddy ... for where I live it`s always over 40 % , day or night . Under 40 % would be a massive High front , temperatures in the upper 80` - 90 degree area . Humidity is great for a young plant , but I would agree anything over 70 % humidity late ( week 7 or 8 in a 8 week strain ) in flower does risk mold or powder mildew .
 
vostok

vostok

Well-Known Member
To the majority of growers here, fans are used to remove excess heat, not a thought given to the STOMATA's or pours on the leaf that actually allow plants to breathe, they suck in C02 and pooped out 02, messing with this ...like with you!!!.. will affect yield, so always have some venting or even a small pc type fan to stimulate wind, you have a seedling now, avoid the big extract fan stick with the small 4 inch until big enough ..good luck
 
K

Kili Frunza

Active Member
posterart said:
Kili , Hey buddy ... for where I live it`s always over 40 % , day or night . Under 40 % would be a massive High front , temperatures in the upper 80` - 90 degree area . Humidity is great for a young plant , but I would agree anything over 70 % humidity late ( week 7 or 8 in a 8 week strain ) in flower does risk mold or powder mildew .
Click to expand...
From my experience whenever i had humidity over 50% in late flowering stage i had problems with mold that is why i always use a dehumid pack or two in the grow when it starts flowering. After week 3 of flowering i keep it at 30% but that its just me, if you never had problems with mold at 50% then keep it up. I am talking of experince and what i've read. Peace

EDIT: And ofcourse theres a big variabile to consider and that is the strain you grow, some are more sensitive to mold than others.
 
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posterart

posterart

Member
Today San Francisco , CA 67 degrees 73 % humidity . Not like East Coast humidity , no pm or mold . I would use a dehumidifier if it was the winter , raining and I was a week from harvey .
 
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