If you're an expert on ventilation, I could use your input!

wk420

wk420

Active Member
I am trying to raise the humidity in my grow tent. Here's the pertinent details: 3x3x6 tent w/ humidifier in it. Exhaust runs @ around 240 CFM. Intake comes from inside bedroom. Tent humidity is around 40-50%, intake/bedroom air is about 30-45%. Tent temp is 84. Humidity/Temp monitor is sitting in the pot next to one of my girls. Using 900w led. Anywaysss, when I first wanted to raise the humidity I put a humidifier in the tent but to my surprise even with the humidifier all the way up, I was only able to achieve about a 10% higher humidity from the air in the bedroom. I attempted to add a second humidifier, also turned all the way up, with the same results. I was thinking and thought that maybe the exhaust fan is pulling the air out so quick that the mist from the humidifiers isn't even reaching the plants it's just going out the machine and straight out the tent. The exhaust fan I have is not adjustable, so what do I do here? Less intake? More intake? I had another idea, not sure if it would make a difference or not but here it is... for my intake I was thinking of taking the humidifier out of the tent and first trying to put it in the bedroom and achieve the desired humidity in there so that all intake air is already at the right humidity. If that doesn't work my final thought was to use one of my huge plastic storage totes, put the humidifiers in there, cut a whole on one side for intake, another on the opposite side for exhaust that has a duct fan hooked up to it and a duct running to the intake of my tent. The thought was that I would be able to achieve a higher humidity in such a smaller environment and then just pump the air out of the big plastic tote into the tent at the same rate if not higher than the tents exhaust fan. If you have any ideas or input or can share any experiences with me I would greatly appreciate it! Thanks
 
makka

makka

Well-Known Member
Maybe a bucket of ice with a fan blowing across the surface and place in take ckose to it just a thought
 
justugh

justugh

Well-Known Member
wk420 said:
I am trying to raise the humidity in my grow tent. Here's the pertinent details: 3x3x6 tent w/ humidifier in it. Exhaust runs @ around 240 CFM. Intake comes from inside bedroom. Tent humidity is around 40-50%, intake/bedroom air is about 30-45%. Tent temp is 84. Humidity/Temp monitor is sitting in the pot next to one of my girls. Using 900w led. Anywaysss, when I first wanted to raise the humidity I put a humidifier in the tent but to my surprise even with the humidifier all the way up, I was only able to achieve about a 10% higher humidity from the air in the bedroom. I attempted to add a second humidifier, also turned all the way up, with the same results. I was thinking and thought that maybe the exhaust fan is pulling the air out so quick that the mist from the humidifiers isn't even reaching the plants it's just going out the machine and straight out the tent. The exhaust fan I have is not adjustable, so what do I do here? Less intake? More intake? I had another idea, not sure if it would make a difference or not but here it is... for my intake I was thinking of taking the humidifier out of the tent and first trying to put it in the bedroom and achieve the desired humidity in there so that all intake air is already at the right humidity. If that doesn't work my final thought was to use one of my huge plastic storage totes, put the humidifiers in there, cut a whole on one side for intake, another on the opposite side for exhaust that has a duct fan hooked up to it and a duct running to the intake of my tent. The thought was that I would be able to achieve a higher humidity in such a smaller environment and then just pump the air out of the big plastic tote into the tent at the same rate if not higher than the tents exhaust fan. If you have any ideas or input or can share any experiences with me I would greatly appreciate it! Thanks
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hey man this is a easy one ........it is the humidifer tech that is the trouble

the standard ones will not put it out in a way that will work for u(it passes out to quick) .......u need to change over to a ultra sonic
http://www.amazon.com/Homdox-Ultrasonic-Humidifier-Constant-Nightlight/dp/B01264ZIYU

it is not like the normal ones this little 3 inch disk in there vibrates at a high enough lvl anything liquid that touches it mists up .........with a cool mist setting u will raise the RH in the tent the system is digital so u will keep that lvl with in 5 % or so (little tweaking u will have it mastered)....the warm mist will make it rise up need your ejection point for tent ....the cool mist will keep it low to grow and will raise up as the temp of the air does it is in so will make a cycle going mixxing with intake air

i use one of these in my drying tent to hold it to lvl for me like a giant humidor

as for the speed of the fan a lower powered one would work better but is not needed........it just means u will be filling the tank every 36 hours 72 hours

just make sure u use filtered water in the system other wise u might need to replace the filter feeding the humidifier (had one like this one ....i think that model was last years mine was a 2013 have not replaced the filter for it yet due to using filtered water in it)
 
astronautrob

astronautrob

Well-Known Member
You could buy a speed controller for the fan and turn it down, that might be your easiest option. Why are you trying to raise your humidity anyways? 40-50% is completely fine. I grow with 20% RH, sometimes even lower, through veg and flower and it's fine. It seems like your spending a lot of time/money on a problem that isn't even a problem....
 
mean.green

mean.green

Well-Known Member
astronautrob said:
You could buy a speed controller for the fan and turn it down, that might be your easiest option. Why are you trying to raise your humidity anyways? 40-50% is completely fine. I grow with 20% RH, sometimes even lower, through veg and flower and it's fine. It seems like your spending a lot of time/money on a problem that isn't even a problem....
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I see people all the time on here buy humidifiers and I have always wondered why also...
 
astronautrob

astronautrob

Well-Known Member
mean.green said:
I see people all the time on here buy humidifiers and I have always wondered why also...
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I agree. Obviously there is a sweet spot of RH, just like there are with all the facets of growing, but I've found that having a low RH has not hindered me in any way.
 
mean.green

mean.green

Well-Known Member
astronautrob said:
I agree. Obviously there is a sweet spot of RH, just like there are with all the facets of growing, but I've found that having a low RH has not hindered me in any way.
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I understand using humidifiers for a slow dry after harvest. For clones just use a humidity dome. But other than that the plants going are to benefit from a humidity level below 50% for veg and flower....
 
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astronautrob

astronautrob

Well-Known Member
mean.green said:
I understand using humidifiers for a slow dry after harvest. For clones just use a humidity dome. But other than that the plants going to benefit from a humidity level below 50% for veg and flower....
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True for both cases. For me personally, drying is the only time I aim to raise the humidity in my tent, and then it's as simple as turning off my exhaust fan and it'll usually bump it up 10-15%
 
Bubblegum31

Bubblegum31

Well-Known Member
High RH is the best thing you can do to cannabis ever...
vapor_pressure_deficit_relative_humidity_chart_small.jpg

Am stuck to not more than 60% in mid\late flowering just so the filter works.

If i run seald I would go higher..

Just make sure that the room temps dont get under 20/21C when lights are off so you dont get PM check the chart and read more about vapor pressure deficit in cannabis.

Bubble
 
Bubblegum31

Bubblegum31

Well-Known Member
I just bought two more new Humidifiers plus what I have so I have 3 in tottal now All are altrasonic and use almost no electricity.
 
astronautrob

astronautrob

Well-Known Member
Bubblegum31 said:
In which sense?
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So many ways. There are numerous things that you could argue are the "best thing" you can do for you plants, but high RH? There are so many other facets of growing that would be considered by many much more important than the RH of your grow room. Nutes, lighting, soil, temps, to name a few, would be much more important than RH
 
Bubblegum31

Bubblegum31

Well-Known Member
astronautrob said:
So many ways. There are numerous things that you could argue are the "best thing" you can do for you plants, but high RH? There are so many other facets of growing that would be considered by many much more important than the RH of your grow room. Nutes, lighting, soil, temps, to name a few, would be much more important than RH
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I dont disagree. I agree that RH is a Piece in the whole picture...

But raising RH makes my girls extremely happy, when its humid the leaves are just all standing looking just good!!

I notice my self that High RH is good its not a bad thing.

But like you sayed low Rh is also not going to hinder you.. Its just better!
 
Bubblegum31

Bubblegum31

Well-Known Member
astronautrob said:
Plus having high RH isn't even preferred when flowering...
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Ppl get afried of high RH in flower bcz of rot amd mildew..

If you wanna be safe play 60%

I was also exactly like you..

There is a guy on that forum told me raise it in LATE flower to 60%

And all members on the forum told me NOT to liesten to him...

He was right and all were wrong..

Not here to argue just sayen my word maybe someone will fimd it helpfull and make sense to him!!

Thats it!
 
astronautrob

astronautrob

Well-Known Member
Bubblegum31 said:
I dont disagree. I agree that RH is a Piece in the whole picture...

But raising RH makes my girls extremely happy, when its humid the leaves are just all standing looking just good!!

I notice my self that High RH is good its not a bad thing.

But like you sayed low Rh is also not going to hinder you.. Its just better!
Click to expand...
Fair enough. I just see people on here telling new growers to go buy a humidifier and waste all this money so I just try to give a different perspective on RH and growing. Yea anyone who says raise your RH in flower should not be giving advice, you're right that's crazy. Agreed, not here to argue either, but I do like hearing how other people grow I'm glad we could actually talk without fighting seems like there's so much of that on here :bigjoint:
 
mean.green

mean.green

Well-Known Member
what are the numbers in the middle of the chart?
Bubblegum31 said:
High RH is the best thing you can do to cannabis ever...
View attachment 3656092

Am stuck to not more than 60% in mid\late flowering just so the filter works.

If i run seald I would go higher..

Just make sure that the room temps dont get under 20/21C when lights are off so you dont get PM check the chart and read more about vapor pressure deficit in cannabis.

Bubble
Click to expand...
 
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