Inline fan is lowering my humidity

New to rollitup and never grown just set up my 4x4grow tent set my 600 mh and have a 340 cfm inline duct blower everytime I turn it on humidity drops 10-16% and I need at least 50-60% for veg pleas help I've 2 gallons of water that I cut in half and just bought a humidifier and the damn humidity still don't go up any advice to raise humidity during veg and do I have to downgrade on the inline blower???
 

Rancho Cucamonga

Active Member
You can grab a fan speed controller and dial the intake cfm down. Unless you are doing clones you only need around 50% for the entire grow period. Are you using the humidifier in the grow room? If so move it near the intake outside of the grow room, that may allow the higher RH air to enter and raise grow room RH more, if it is outside the grow room stick it inside.
Dealing with low humidity is much cheaper then dealing with higher humidity. My de-humidifier takes 600 watts to run and I have to run it 18 hours a day half the year. Be sure to use distilled or filtered water in that humidifier, don't want to have mineral deposits all over the place.
You need lots of air, do not downgrade on intake or exhaust. There you go, turn up the exhaust cfm.
 

DOYOUSMELLTHAT

Well-Known Member
I have approx. a 4x4x8 with a 600. I too freaked out about low RH. Mine is running about 35 during the day...got as low as 25. I cut my exhaust with my light at night( I have a 6 in. inline fan shooting right to my attic through the ceiling for exhaust, and one passive intake at the bottom..no reason for a fan yet..my heat is hovering at 79 where the plants are) At night I have the inline fan cut off with the light, and have the humidifier on..so for 6 hours its probably at 60-80 humidity during veg. and drops to 65-70 temp.

My babies are growing great! Don't sweat it about low RH in veg, high RH in Flower makes them rot. From what peeps on here say.
My 4x4 is within a walk in closet, so I put my humidifier on the OUTSIDE passive intake of my tent..and RH is hitting 40% now. I don't know if this possible for you, but when I had the humidifier INSIDE the tent, my fan just sucked it right out.

I ordered a fan controller from Amazon so I can slow down my fan somewhat. Im happy with 45% no need for another humidifier to kick the power up. As of yet. It should be here soon in the mail, holla at me and ill let you know how it worked. I dont want to sacrifice high heat for high humidity. Keep them watered and humidity shouldn't be a problem..they pull moisture from the soil, not just their leaves!http://www.amazon.com/gp/product/B003URBQ1M/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A19I28AKMOKQVB
 
I have approx. a 4x4x8 with a 600. I too freaked out about low RH. Mine is running about 35 during the day...got as low as 25. I cut my exhaust with my light at night( I have a 6 in. inline fan shooting right to my attic through the ceiling for exhaust, and one passive intake at the bottom..no reason for a fan yet..my heat is hovering at 79 where the plants are) At night I have the inline fan cut off with the light, and have the humidifier on..so for 6 hours its probably at 60-80 humidity during veg. and drops to 65-70 temp.

My babies are growing great! Don't sweat it about low RH in veg, high RH in Flower makes them rot. From what peeps on here say.
My 4x4 is within a walk in closet, so I put my humidifier on the OUTSIDE passive intake of my tent..and RH is hitting 40% now. I don't know if this possible for you, but when I had the humidifier INSIDE the tent, my fan just sucked it right out.

I ordered a fan controller from Amazon so I can slow down my fan somewhat. Im happy with 45% no need for another humidifier to kick the power up. As of yet. It should be here soon in the mail, holla at me and ill let you know how it worked. I dont want to sacrifice high heat for high humidity. Keep them watered and humidity shouldn't be a problem..they pull moisture from the soil, not just their leaves!http://www.amazon.com/gp/product/B003URBQ1M/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A19I28AKMOKQVB
You can grab a fan speed controller and dial the intake cfm down. Unless you are doing clones you only need around 50% for the entire grow period. Are you using the humidifier in the grow room? If so move it near the intake outside of the grow room, that may allow the higher RH air to enter and raise grow room RH more, if it is outside the grow room stick it inside.
Dealing with low humidity is much cheaper then dealing with higher humidity. My de-humidifier takes 600 watts to run and I have to run it 18 hours a day half the year. Be sure to use distilled or filtered water in that humidifier, don't want to have mineral deposits all over the place.
You need lots of air, do not downgrade on intake or exhaust. There you go, turn up the exhaust cfm.
New to rollitup and never grown just set up my 4x4grow tent set my 600 mh and have a 340 cfm inline duct blower everytime I turn it on humidity drops 10-16% and I need at least 50-60% for veg pleas help I've 2 gallons of water that I cut in half and just bought a humidifier and the damn humidity still don't go up any advice to raise humidity during veg and do I have to downgrade on the inline blower???
damn man thanks bro ill try it out ....the humidifier is inside ill put it outside and let the intake fan suck it in and the timer I had no idea you can buy a controller for it
 

DOYOUSMELLTHAT

Well-Known Member
I tried venting my exhaust back into my walkin closet outside my box back in through the ceiling to keep the cycled air in, rather than blow it into my attic!!! TEMP went up in grow to 86!!! Def nono!

I pulled my humidifier outside of box and put in front of the intake fan in bottom corner, but I think I still am going to grab another high powerd humidifier for $50-75 with some real output in addition. WATCH THE LIGHTS ON THE HUMI WHEN YOU BUY>>NO GO FOR WHEN THEY GO INTO FLOWER. I had to spray my pink pig and the red light on inside it is still dimly showing through.
 

Badseed69

New Member
New to rollitup and never grown just set up my 4x4grow tent set my 600 mh and have a 340 cfm inline duct blower everytime I turn it on humidity drops 10-16% and I need at least 50-60% for veg pleas help I've 2 gallons of water that I cut in half and just bought a humidifier and the damn humidity still don't go up any advice to raise humidity during veg and do I have to downgrade on the inline blower???
I would just run a fan and keep your tent door open a little so it gets some fresh air. I have the same size tent only I use LED and I always have humidity at like 45 to 50
 

GeneBanker

Well-Known Member
Dont buy a humidifier for this problem. Buy a fan speed controller. If you do math you are exhanging the air in your tent almost 3 times a minute, and nearly 180 times an hour. Maybe a rooftop evap cooler could keep up with that exchange rate.
 

Badseed69

New Member
Dont buy a humidifier for this problem. Buy a fan speed controller. If you do math you are exhanging the air in your tent almost 3 times a minute, and nearly 180 times an hour. Maybe a rooftop evap cooler could keep up with that exchange rate.
This guy is a bigger like myself. Talking in Marjuanna science is only going to confuse him. Talk to him .
 

GeneBanker

Well-Known Member
This guy is a bigger like myself. Talking in Marjuanna science is only going to confuse him. Talk to him .
Fair enough, and I see your point. To the O.P, i read alot of different views on how much air flow you need. Theres a lot of factors that go into figuring your fan needs. If humidity is your only problem, and dialing a fan down wont starve a light of cool air,I would suggest simply turning it down.
 

ezrolling

New Member
I would just run a fan and keep your tent door open a little so it gets some fresh air. I have the same size tent only I use LED and I always have humidity at like 45 to 50
Keeping the grow tent open isn’t a big deal when flowering?? Like the smell or any of that nature?? My humidity is up to 60-67% door closed and drops to 51% open. Is 50% humidity ok for flowering stage?
 
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hotrodharley

Well-Known Member
Keeping the grow tent open isn’t a big deal when flowering?? Like the smell or any of that nature?? My humility is up to 60-67% door closed and drops to 51% open. Is 50% humility ok for flowering stage?
The more humility a man has the better a man he is.

As to humidity - you want low humidity in flower
 

ezrolling

New Member
Thanks for being a good sport. Stop doing that driving . Your humidity is a dream for flowering.
Lol ik driving and texting not good...I wanted to know how can you keep the humidity down besides keeping the tent open because soon as I close it the humidity rises but when it’s open it drops to 50% I want to be able to control it so when it’s time to flower I won’t have that problem. I’m only a few weeks into vegging and I have a inline exhaust fan and two circulating fans for air flow.. if I put an intake fan to pull air from outside of the grow tent will that help with humidity? I tried a small dehumidifier and it didn’t really do anything
 

hotrodharley

Well-Known Member
Lol ik driving and texting not good...I wanted to know how can you keep the humidity down besides keeping the tent open because soon as I close it the humidity rises but when it’s open it drops to 50% I want to be able to control it so when it’s time to flower I won’t have that problem. I’m only a few weeks into vegging and I have a inline exhaust fan and two circulating fans to for air flow.. if I put an intake fan to pull air from outside of the grow tent will that help with humidity? I tried a small dehumidifier and it didn’t really do anything
Exhausting the air out of the tent during lights out is about the best you can do without running a room dehumidifier. Trying to dehumidify a tent is impossible. .
 

ezrolling

New Member
Exhausting the air out of the tent during lights out is about the best you can do without running a room dehumidifier. Trying to dehumidify a tent is impossible. .
I’m using a 4 inch inline fan now in 5x5 do you think a 6 inch inline will help more than the 4 in
 
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