Humidity

Natures Cure

Active Member
I'd like to hear opinions regarding humidity. I've heard . . . Dont worry about it much at all, I've heard 50-60% which seems very reasonable. And I had someone else tell me don't go below "Zero" (which was obviously a joke) but I have to know the iron clad rule on humidity.

If I do need to maintain a specific relative humidity and are forced to use a humidifier should it be a certain water, i.e. distilled. Currently, I'm using a humidifier and it's leaving deposits on my mylar. I'm pretty sure that distilled water should take care of the the deposits/salt like film.

Thanks in advance for the posts. Rep me plz ;-)
 

DTR

Active Member
i had low humidity in veg so i got a coolmist humidifier and got powdery mildew im doing alot of things wrong tho but next run im only going to worry about reducing it
 

sambo020482

Well-Known Member
high humidity for vegging ideal 50-60% lower for flower 35-40% ive also heard that lowering to 20-30% in the last 2 weeks of flowering will make the buds more better.
 

sambo020482

Well-Known Member
i had low humidity in veg so i got a coolmist humidifier and got powdery mildew im doing alot of things wrong tho but next run im only going to worry about reducing it
i and a few friends have always used humidifiers and never had problems with powdery mildew,

they are cheap and in imo the best way to raise the humidity, much more expensiv if you gotta lower humidity tho.
 

riddleme

Well-Known Member
Every part of the growing equation is very important, a great grow depends on the sum of all parts, understanding how plants work and what they want makes it easier to dial in all the parts for a perfect enviroment.

the way to tweak humidity is via a heat index calculator, the combo of temp and humidity gives you a heat index, within the acceptable ranges your heat index should be a few points higher than the actual temp without going over 78F as an example mine is temp 72 humidity 33% heat index = 76.5.

This allows the plant to transpire comfortably without any stress IF the other conditions are dialed in right such as light, plants want between 3000 and 6000 lumens of the proper spectrums of light (think sun)

not enough light = stress

too much light = stress

stress = slower growth, smaller yields

the other equation is CO2 which is best supplied in the form of FRESH air and lastly is water which should be PH'd to between 5.6 and 5.8 (the PH of rain)

If these are dialed in properly you have effectivly created a perfect enviroment for MJ growing

Nutes and Medium are important and must be dialed and controled as well but do not have as much effect on plant response to stress as the other factors

All of this is explained in detail in my NooB Advice thread
 

DTR

Active Member
sambo i did not mean dont get a humidifier the coolmist actually lowered my temp which was good im pretty sure my clones came with powdery mildew and raising the rh just let it have a outbreak that otherwise i probably wouldnt of seen with my low rh im just saying my plants were doing fine with low rh and in doing something i didnt need to i created a problem for myself
your rh wont give you powdery mildew
Powdery mildew diseases are caused by many different species of fungi in the order Erysiphales.
i apologize for any confussion
 

Natures Cure

Active Member
i had low humidity in veg so i got a coolmist humidifier and got powdery mildew im doing alot of things wrong tho but next run im only going to worry about reducing it
I am infact using the cool mist humdi. I'm figuring that powdery white residue is the reminants of the atomized tap water. I don't think it's mildew or harmful beyond the fact that those deposits must be being left on the plat too . . . making it hard for the plants to breath and prespire. :weed:
 

Natures Cure

Active Member
I am infact using the cool mist humdi. I'm figuring that powdery white residue is the reminants of the atomized tap water. I don't think it's mildew or harmful beyond the fact that those deposits must be being left on the plat too . . . making it hard for the plants to breath and prespire. :weed:
Right now I'm at 22% humidity and 79 degrees (f). It's hard for me to tell if that low humidity is a problem. I just transplanted my babies from a onesite bubbler to a six site bubbler. I had 7 babies and I had to cannibalize (i fkn ate it, lol). As her stem broke during the process. but that's fine cause I had 7 babes and only six places. I don't know if any of you guys ever ate your 7 inch plant but i did and it tasted great!
 

DTR

Active Member
@Natures Cure mine is definitely powdery mildew the humidifier did not cause it but helped allow the outbreak if your not sure what the spots are and you see them on your plant get a handheld microscope 60~100x zoom $10~13 and look at the pix online of powdery mildew and other things its very easy to identify under a scope and fairly easy to manage if you catch early but im pretty sure it will only grow on the plant so if you have it on your walls and other things i wouldnt worry
 

SickSadLittleWorld

Well-Known Member
My humidity never cracks 30% in my tent and I've made no attempts to control it. In my experience, low humidity during veg isn't a big deal but high humidity during flower is something to take very seriously.
 

sambo020482

Well-Known Member
My humidity never cracks 30% in my tent and I've made no attempts to control it. In my experience, low humidity during veg isn't a big deal but high humidity during flower is something to take very seriously.
i dont no much but i fink low humidity during veg will just make the plant grow slower, and yeah high in flower is bad!!! i got a small bit of the dreaded mold on a lower bud cause of high humidity in my last grow,

and if ya wana raise it just get yaself a cheap humidify they work well in a tent imo.
 

HomeGrown420baby

Well-Known Member
RH for veg can be anywhere from 40-80 and for flower it can be anywhere from 30-50 lots of people drop there rh during flowering under 30..i never do and i always got hella thc on my buds i think its overexagerated and rh levels arent as serious as people think..when i veg i have my rh around 50-65 and for flower i drop it to 35-50..during lights of it jumps to 55-60 so if im flowering i throw a dehumidifier in there at night to keep it below 50 at least
 

Natures Cure

Active Member
My humidity never cracks 30% in my tent and I've made no attempts to control it. In my experience, low humidity during veg isn't a big deal but high humidity during flower is something to take very seriously.
forgive me but when you say never cracks 30 do you mean go below or above.

Second can you elaborate a bit more of humidity during flowering.

thanks
 

SickSadLittleWorld

Well-Known Member
forgive me but when you say never cracks 30 do you mean go below or above.

Second can you elaborate a bit more of humidity during flowering.

thanks
Yeah, I guess that needs some clarification...it never goes above 30% during lights on. They do consume more water than if they were in a more humid environment but I haven't seen any other ill effects.

High humidity during flowering can lead to bud rot and mold, basically destroying your crop. Keep it as low as possible during that time to avoid any problems.
 
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