Madmax said:

This is where having a dehumidifier works..you just select a setting say 60% for early flower then later select 50% .you wont have to reset every nite then..mines going 24/7..it actually heats the room a little of the night and keeping humidity in check..kills 2 birds with one stone.

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I’m so torn now on wut to do! Earlier a lot of you said I would be alright now I’m worried. I feel I’m having a harder time keeping the RH up rather then having it exceed where I need it to be. Even at night but it reaches the set RH a lot easier during lights off so the humidifier kicks on every once in awhile to keep it at around 60%.

ImpulsiveGrower said:

Well I’ve always noticed in the summer it’s hot a balls up in the attic so I figured my little closet grow wouldn’t affect the attic that much since it seems humid already during the summer. My house is a ranch style home so the attic is not super tall but it’s roughly 30x60 ft. I’ll investigate that further and try to vent it out the roof somehow but I just didn’t think my closet grow would cause that much humidity in my particular attic. So what’s VPD mean? And still looking for the answer about night time Rh. It’s supposed to be like 10%lower at night? Without the humidifier kicking on during the night the air being pulled into the space is wayyyyy lower that 10 percent the RH of the air being pulled into the space is in the upper 30z (38-40) so I feel I still need my humidifier to kick on but instead of 60% I should set it for 50% at night?

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O link a thread I did on VPD for ya.. explains most of it.

Aqua Man said:

O link a thread I did on VPD for ya.. explains most of it.

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Checking it out now thanx!

ImpulsiveGrower said:

I’m so torn now on wut to do! Earlier a lot of you said I would be alright now I’m worried. I feel I’m having a harder time keeping the RH up rather then having it exceed where I need it to be. Even at night but it reaches the set RH a lot easier during lights off so the humidifier kicks on every once in awhile to keep it at around 60%.

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Easy... the thread I link is a guide and ideal conditions roughly but genetics and other factors can change the ideals. For instance I find sativa leaners like the more humid end and indicas like the drier end of VPD.

But I can assure you there is a LOT of wiggle room on humidity. What you don't want is to hit dew points or have a humidity so high they slow transpiration to much. Drier is the lesser of the evils.

I mean if under very high light it becomes more of a factor but moderate or low they grow usually without issue Well under 40%.

Don't go all balls deep on it.... the most important though is keeping humidity in check after lights out. As it will spike from the temp drop because we'll.... Relative humidity is just that Relative to temperature.

Sorry to worry you brother.i shouldnt have said anything as im in shed outdoors and what aqua said seems your not venting back into grow area your humidity should b around 50% or under really..much more stable than in a shed .im at war with it in my climate lol.. fans circulating the air inside room helps big time..

Aqua Man said:

Don't go all balls deep on it.... the most important though is keeping humidity in check after lights out. As it will spike from the temp drop because we'll.... Relative humidity is just that Relative to temperature.

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Ya I’m going to have to dig deeper about this subject it’s really taking things to the next level in terms of environmental control. So wut I got from it is the lower RH set for night will increase nutrient and water intake thus making you plant grow faster? So I’m in veg right now and I like my RH at like 60-65% so at lights off I should set it to like 50-55? Then bring it back up during the day back to 60-65%? I know you can get really deeper into it but is that kinda wut yours getting at?

Madmax said:

Sorry to worry you brother.i shouldnt have said anything as im in shed outdoors and what aqua said seems your not venting back into grow area your humidity should b around 50% or under really..much more stable than in a shed .im at war with it in my climate lol.. fans circulating the air inside room helps big time..

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Nah it’s all good man I just want this first grow to go well and I thought I obsessively learned most of the information I need to get they each stage of growth.

ImpulsiveGrower said:

Ya I’m going to have to dig deeper about this subject it’s really taking things to the next level in terms of environmental control. So wut I got from it is the lower RH set for night will increase nutrient and water intake thus making you plant grow faster? So I’m in veg right now and I like my RH at like 60-65% so at lights off I should set it to like 50-55? Then bring it back up during the day back to 60-65%? I know you can get really deeper into it but is that kinda wut yours getting at?

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Kinda but not for that reason. Lower humidity at night is because the plants don't transpire much and the humidity has little effect on uptake for that reason when the lights are out. The lower humidity creates less chance of condensate. It's not that humidity the same is bad it's just not needed so no need to run your humidifier and waste power and water.

You can absolutely run the same humidity day and night... just to make clear it's just not needed. What you do need to worry about is the dew point.

Decent air exchange and airflow through the plants is important and humidity only becomes a real issue when its to high in most cases. So if yours low it's not likely to cause you issues.

While VPD is a good tool the key is just don't hit the dew point. It's not as likely to make a huge impact for your grow results at a newer skillset or without very high light.

While I am all for VPD there is a limit to its importance and impact so don't go all nuts trying to make the perfect humidity.... you just need to keep it in a decent range. Generally 40-60% is a good place for most growers.

I just wanted to link it to give some explanation on how and why. Not get you to panic and go balls deep buying a bunch stuff that's going to make little impact.

Found this earlier tonight and sharing.