Winter Growing / Humidity & Temp

grow tiger

grow tiger

Member
I have a closet set up n I just put two three buckets of water in there, under the lights and in the line of the fan , so my fan blows on one of the buckets n the lights shine on it , this brought my humidity from 30% to 60% without any humidifiers or anything . .. I also use a spray bottle n spray the entire room n the back of the fan before I shut the door .... This worked for me . but idk ur set up or how big of abspace ur workn with.
 
Logan Burke

Logan Burke

Well-Known Member
Colorado Jay said:
Unfortunately there's not much I can do to get the humidity higher, I put a humidifier in the room and ran it for days and could only ever get the humidity from 16% up to 17%. If I shut down the ventilation fans then the humidifier will keep it more humid but then it gets way too hot...
Click to expand...
Then I wouldn't stress it too much, as Nullis has said quite a few times: Cannabis is a very hardy, durable plant, and something such as low humidity, unless it's like 1%, will at the worst will make your plant drink more water then usual and perhaps cause cracks on leaves. I could be wrong, but I believe a real low humidity can cause that, but don't take my word on it because I don't know if it's 100% true. Anywho though, so long as your temp, nutrients, lights, foliage and roots are in well order, then you shouldn't worry about your humidity (again, unless it's like 1%). Mine was about 20-25% RH in veg and I've some beautiful young flowers.
P.S. - I also added a humidifier, and it had to run for nearly 3 days in a fairly small space w/ good ventilation before I even saw a noticeable rise in RH. So, perhaps leave it running by your air intake or by your plants for a few days before checking to see if it's raised? By the way, if I'm wrong on any of the info I've posted just tell me, I can't stand people who stick their nose in the air and say "Uhm, that's incorrect, do your homework". Like they weren't doing the exact same thing their first couple months on RIU. Sorry for the lil rant there...haha, happy growing my friend and keep us posted on your situation. :mrgreen:
 
latewood

latewood

Active Member
Have you considered that your measuring device is off calibration? I cannot believe that you cannot raise the humidity with a humidifier running. Just satin' :)
 
N

nuggly

Active Member
The theory behind higher humidity for veg and lower humidity for flower is called a vapor pressure deficit or VPD. The theory is low humidiy raises the pressure inside the plant cells causing the stomata to close. Plants signal it as a draught conditions and closes the stomata to conserve water those slowing nutrient exchange and metabolism.
It's more than just humidity leaf temperature is a main factor as well. Grower using hps would likely have higher VPD than an led grower.
Of course strain and genetics plays a role as well some strains may do fine in dry conditions. However MJ's response to dry conditions is to produce resign to seal in water and stop, water loss, so it's a balancing act.
My experience is when I raised temp and humidity I got really good grow lots of yield but not good quality. I ran perpetual system so I did not have much choice so ran 80 degrees and 35% rh and got good results both yield and quality.
The ideal situation is to run higher temps and humidity for part first of flower and crank down rh as you get toward the end of flower. This will get you max yield and max quality.
Under currents Web page had an excellent chart showing temp, nutrient and humidity levels recommended for a grow. Can't find it now but will post it later when I get home.

Nuggly
 
N

nuggly

Active Member
nuggly said:
The theory behind higher humidity for veg and lower humidity for flower is called a vapor pressure deficit or VPD. The theory is low humidiy raises the pressure inside the plant cells causing the stomata to close. Plants signal it as a draught conditions and closes the stomata to conserve water those slowing nutrient exchange and metabolism.
It's more than just humidity leaf temperature is a main factor as well. Grower using hps would likely have higher VPD than an led grower.
Of course strain and genetics plays a role as well some strains may do fine in dry conditions. However MJ's response to dry conditions is to produce resign to seal in water and stop, water loss, so it's a balancing act.
My experience is when I raised temp and humidity I got really good grow lots of yield but not good quality. I ran perpetual system so I did not have much choice so ran 80 degrees and 35% rh and got good results both yield and quality.
The ideal situation is to run higher temps and humidity for part first of flower and crank down rh as you get toward the end of flower. This will get you max yield and max quality.
Under currents Web page had an excellent chart showing temp, nutrient and humidity levels recommended for a grow. Can't find it now but will post it later when I get home.

Nuggly
Click to expand...
http://cch2o.com/general-recommendations/

CCH2O-Recommendations-Graph-1024x743.jpg
 
Logan Burke

Logan Burke

Well-Known Member
Is it just me being an idiot, or is that chart hard to follow?....It seems like solid info, just difficult to understand
 
N

nuggly

Active Member
Yes it was hard to follow at first. But each colored line has a different index. Black is humidity just find the humidity scale which is marked at the bottom on the chart. Week or timeline is across the top. Oh and if you use ppm instead of ec the highest ec is about 1050 ppm and lowest ec is like 200 depending on conversion table metbod.

This is were a environment controller lIke the iponic really shines. You can preprogram all those variables into the controller except ppm and it will set each value different for each week of your grow. They call them a "grow curves". You set it up and each week or day is a different setting for day and night. You do it once save it to memory card then load growth curve for your strain and you don't have to touch it again. Logs data as well to check everything is staying within the parameters. Very nice controllers but they are pricey.
 
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Logan Burke

Logan Burke

Well-Known Member
Yes after waking up, grabbing some coffee and seeing through a pair of fresh eyes I'm starting to understand the chart, haha.
 
Logan Burke

Logan Burke

Well-Known Member
Lmao I think that was my problem last night bro! I had just torched the last of my hash while reading that chart.... :bigjoint:
 
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