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Need help raising relative humidity in a larger room

NugHeuser

Well-Known Member
I'm trying to follow guidelines(the graphs online) for a healthy vaper pressure deficit on my plants. I currently am only running one 630 watt double ended ceramic medal halide inside a 9x10 room and at the moment only one month old plant under it, the temps are nice, around 81 degree highs, but because this is an open de light it's sucking a lot of moisture out of the air.

I've been misting the walls and also a little bit of searches on raising rh, most answers to the threads were unrelated to the questions or were saying "it's fine, don't worry about it". So I ended up going to Wal-Mart and paid 80 bucks for a thin tower evaporative humidifier(1.7 gal capacity) they only had one size bigger that advertised for 2000 sq ft for 90 dollars(I didn't see sq footage specified on the model that I bought but figured it was in the ball park of the 90 dollar model).

So now after a couple days, I have 2 buckets of water with wet towels draped over the edge(both within a foot of the plant), misting the walls(usually only get to mist in the evenings and the mist is usually evaporated after 30 to 45 mins), and this humidifier(on high, does not blow air very hard for high) and a fan behind it blowing the moist air toward the light and plant.
My rh is maxing right about at 60 percent(lights on) but that's when I'm really working to raise it (resoaking towels and misting walls) which I only get to do for a couple hours each evening because I work so much. When I got home from work rh was 50%, 5 hours after lights on. I'd like to have control up to about 70 percent, even more would be nice. Just doing what I've done the past 4 days or so(When I started experimenting with raising humidity) seems to have caused my plant to explode as far as rapid growth goes and just looks overall healthier.
So any more tricks or recommendations for units that will actually get the job done I would greatly appreciate. Also it's just an enclosed finished room (no windows) in my basement if that makes a difference. Rest of basement seems to stay around low 60s to mid 70s for rh depending on weather outside. At dark in the grow room the rh does rise to mid 60s without the humidifier or misting.
 

SouthCross

Well-Known Member

NugHeuser

Well-Known Member
Vaper pressure deficit. Under specific rh and temps the plants stomata(I think stomata is the word I'm looking for) open up to the fullest taking in more CO2 and and allowing for maximum growth. And as long as temps are kept above a certain range it makes it tougher for mold to grow and you will get the most growth out of your plant(s). Mainly don't want temps dipping down into the 60s. Upper 70s as lows from everything I've watched and read does well at keeping mold at bay, and long as there are not major environmental swings(rh and temp).

I mainly want the higher humidity for vegetative growth, but I still plan keeping the rh up a bit even through flowering. The last 2 or 3 weeks I'll get it dropped down closer to 40%. All while doing this I have to be able to keep temps up and have good circulation and I shouldn't have problems.

I've been reading up on VPD and watching YouTube vids on it and this is kind of what I'm gathering.
 

ChaosHunter

Well-Known Member

Moldy

Well-Known Member
Lucky bastard! I can't get over 20% RH so fuck it! They suffer in veg and early flower but in spite of my handle I never get any mold.

A small swamp cooler would be nice but that's a hassle to lol.
 

stoned-monkey

Well-Known Member
running co2? sounds like getting extra co2 is the point right? sealed room can run out (low anyway) of co2 quickly. I would like to see a grow journal from you on this run.
 
Last edited:

stoned-monkey

Well-Known Member
another option is set up mister/s like an aeroponics (cloners use them a lot) and mist the plant directly on a timer, sorta like at the grocery store where they mist the lettuce. a fogger may work also, plus then you can fog for pest or mold if needed.
 

ChaosHunter

Well-Known Member
My humidifier is a fog type and I have a 1/2 line going into my tent. I have the dial turned all the way up and set the controller to what ever I want the RH to be. Sever OCD but its fun to be able to dial in the environment to what ever you want it to be.
 

NugHeuser

Well-Known Member
Thanks for all your guys info and experiences. I'll be able to reply back a little better when i go on my lunch break
 

NugHeuser

Well-Known Member
running co2? sounds like getting extra co2 is the point right? sealed room can run out (low anyway) of co2 quickly. I would like to see a grow journal from you on this run.
No I'm not running co2. I actually don't know much about co2 but my room is not sealed because I have to make sure I have no odor outside so I run an 8" inline fan and filter at 740cfm. I mean besides that and a 6" fresh air intake on a speed dial the room is sealed.
But I believe having all that air movement would make things screwy as far as co2. Filling my house with co2? Co2 constantly running out my exhaust which would require more co2? And if I sealed the room then i would have odor issues right? Like I said I may be wrong as I haven't really done much reading up on co2. I would think that at minimum I should have a sufficient amount of co2 just from the normal amount floating around my house because of the constant replacement of air in the grow room. And yes I'll most likely be making a grow journal. I will be running some Alien Rift and Malibu Pie along with a couple others
 

NugHeuser

Well-Known Member
running co2? sounds like getting extra co2 is the point right? sealed room can run out (low anyway) of co2 quickly. I would like to see a grow journal from you on this run.
But now thinking about it, being on the topic of co2, that would work hand in hand with vpd by running extra co2 since the plants would be "breathing" the best at those certain rh and temp levels. And also thinking about it, all the tubers I've watched that talk about vpd run co2 also.

So now I'm wondering if there is a way to incorporate extra co2 while making sure the rest of my house don't fill with it and maintaining odor control at the same time. Is it doable? Maybe at certain parts of the day I'd have to turn the fans off? But then there's the concern of odor if I do that..
 

stoned-monkey

Well-Known Member
I am not familiar with the vpd but if it makes the plant take in more co2 then having that extra co2 would be helpful. if I remember right, typical ambient air has 300-400ppm of c02 cannabis likes 1200-1500 ppm.

so basically co2 is breathed in during the lights on. so you can exhaust air at night. co2 and high(er) temps go well together. also co2 is "heavy" gas so it tends to collect in the lowest area.

odor is controlled through the fact you are not letting the air escape into the rest of the house. not sure how your basement is laid out (obviously) but if it has a door separating the rest of the house that will help, you also can also exhaust the air from the basement rather then grow room to help control odor from that point.

it really sounds like you want added co2 to get the full benefits of VPD.
co2 isn't very expensive around me but with legal growing its sold everywhere, if you are not that lucky of course you have gas suppliers like airgas, but also look into the paintball world cause that's what they use for there markers and sometimes they get discounted rates and then pass that on to their costumers. getting started with co2 can cost a bit though.
 

Lord Kanti

Well-Known Member
Lucky bastard! I can't get over 20% RH so fuck it! They suffer in veg and early flower but in spite of my handle I never get any mold.

A small swamp cooler would be nice but that's a hassle to lol.
Evaporative cooler is the way to go. As far as mold goes, I was able to inoculate my plant in the heat of triple digit summer. Why? An experiment in pest control.
 

Lightgreen2k

Well-Known Member
I'm trying to follow guidelines(the graphs online) for a healthy vaper pressure deficit on my plants. I currently am only running one 630 watt double ended ceramic medal halide inside a 9x10 room and at the moment only one month old plant under it, the temps are nice, around 81 degree highs, but because this is an open de light it's sucking a lot of moisture out of the air.

I've been misting the walls and also a little bit of searches on raising rh, most answers to the threads were unrelated to the questions or were saying "it's fine, don't worry about it". So I ended up going to Wal-Mart and paid 80 bucks for a thin tower evaporative humidifier(1.7 gal capacity) they only had one size bigger that advertised for 2000 sq ft for 90 dollars(I didn't see sq footage specified on the model that I bought but figured it was in the ball park of the 90 dollar model).

So now after a couple days, I have 2 buckets of water with wet towels draped over the edge(both within a foot of the plant), misting the walls(usually only get to mist in the evenings and the mist is usually evaporated after 30 to 45 mins), and this humidifier(on high, does not blow air very hard for high) and a fan behind it blowing the moist air toward the light and plant.
My rh is maxing right about at 60 percent(lights on) but that's when I'm really working to raise it (resoaking towels and misting walls) which I only get to do for a couple hours each evening because I work so much. When I got home from work rh was 50%, 5 hours after lights on. I'd like to have control up to about 70 percent, even more would be nice. Just doing what I've done the past 4 days or so(When I started experimenting with raising humidity) seems to have caused my plant to explode as far as rapid growth goes and just looks overall healthier.
So any more tricks or recommendations for units that will actually get the job done I would greatly appreciate. Also it's just an enclosed finished room (no windows) in my basement if that makes a difference. Rest of basement seems to stay around low 60s to mid 70s for rh depending on weather outside. At dark in the grow room the rh does rise to mid 60s without the humidifier or misting.
I saw what you wrote and many others after this.

Seems like a lot of novice growers are giving you there opinions.

First lets deal with MOLD.

This can happen with High temps and High Humidity..

Vpd works well outside with good ventalation and all. I have the vpd chart that is going around.

The question is which type of plant in specific. You cannot say all either example a "Cactus.... does not fall in this chart.

Co2 Does work well when everything else is in their sweet spots or else its a waste.
 

NugHeuser

Well-Known Member
I am not familiar with the vpd but if it makes the plant take in more co2 then having that extra co2 would be helpful. if I remember right, typical ambient air has 300-400ppm of c02 cannabis likes 1200-1500 ppm.

so basically co2 is breathed in during the lights on. so you can exhaust air at night. co2 and high(er) temps go well together. also co2 is "heavy" gas so it tends to collect in the lowest area.

odor is controlled through the fact you are not letting the air escape into the rest of the house. not sure how your basement is laid out (obviously) but if it has a door separating the rest of the house that will help, you also can also exhaust the air from the basement rather then grow room to help control odor from that point.

it really sounds like you want added co2 to get the full benefits of VPD.
co2 isn't very expensive around me but with legal growing its sold everywhere, if you are not that lucky of course you have gas suppliers like airgas, but also look into the paintball world cause that's what they use for there markers and sometimes they get discounted rates and then pass that on to their costumers. getting started with co2 can cost a bit though.
Oh okay, nice info. Yeah I do have the option of making the room completely sealed, would basically only have to get some gasgetting for my door. So that is an option. And yes it's illegal where I'm at and I don't know what it takes to get the co2. I assume I would probably have to sign documents showing that I bought a tank of co2, I'm sure the law keeps track of that in one way or another, but I wouldn't really know for sure.
But yeah I think I'm going to look further into co2. When you say it can cost a bit to get started with co2, how much are you talking, like hundreds I assume? Surely not thousands I wouldn't think
 

TCH

Well-Known Member
CO2 wont get you on any list. its available at welding supply places, restaraunt supply places, and podsubly paintball places like he mentioned earlier. its pretty commonplace.

Oh okay, nice info. Yeah I do have the option of making the room completely sealed, would basically only have to get some gasgetting for my door. So that is an option. And yes it's illegal where I'm at and I don't know what it takes to get the co2. I assume I would probably have to sign documents showing that I bought a tank of co2, I'm sure the law keeps track of that in one way or another, but I wouldn't really know for sure.
But yeah I think I'm going to look further into co2. When you say it can cost a bit to get started with co2, how much are you talking, like hundreds I assume? Surely not thousands I wouldn't think
 

NugHeuser

Well-Known Member
I saw what you wrote and many others after this.

Seems like a lot of novice growers are giving you there opinions.

First lets deal with MOLD.

This can happen with High temps and High Humidity..

Vpd works well outside with good ventalation and all. I have the vpd chart that is going around.

The question is which type of plant in specific. You cannot say all either example a "Cactus.... does not fall in this chart.

Co2 Does work well when everything else is in their sweet spots or else its a waste.
I saw what you wrote and many others after this.

Seems like a lot of novice growers are giving you there opinions.

First lets deal with MOLD.

This can happen with High temps and High Humidity..

Vpd works well outside with good ventalation and all. I have the vpd chart that is going around.

The question is which type of plant in specific. You cannot say all either example a "Cactus.... does not fall in this chart.

Co2 Does work well when everything else is in their sweet spots or else its a waste.
Well of coarse the type of plant is cannabis if that's what you mean. So mold is the big concern with this. How come for example I see greengenes and medicropper running the vpd with high humidity and are not getting mold, what's the key here? Is it mainly just air movement?

And when you say "when everything's in its sweet spots" (about the co2), what sweet spots are you speaking of? Temp, rh, and good lighting? A sealed in room as well?
 

NugHeuser

Well-Known Member
CO2 wont get you on any list. its available at welding supply places, restaraunt supply places, and podsubly paintball places like he mentioned earlier. its pretty commonplace.
Okay cool. Yeah I saw he mentioned the paint balling. I work at a weld shop too but if it's that easy I'd just contact the gas supplier myself and go pick it up, good knowing that there's no sort of "list"
 
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