low humidity

clandestino · Dec 3, 2008

running 9 600w lights in my flowering room and the humidity is dropping to 28% at times with terrible effects on my yields i tried using an ultrasonic humidifier but it only raised it by 2%. does anybody know of a more industrial cost effective way to raise humidity. i am considering greenhouse misters at the moment but worried it might affect my electrics. anybody out there with similar problems? help help help

Stackin Paper · Dec 3, 2008

Not similar problems m8 but my tent runs as low as 15% with no effects, are you sure its the RH causing the problems?

Finalopagus · Dec 3, 2008

Yea I never had problems with a rH range of 15% - 70% lower towards flower finish. IMO 50% rH 24/7

If you gotta add moisture small fan blow'in on water cheapest, or like me spill shit all over the place and make a huge fuckin' mess. Watch out for moisture on outside windows :talking

clandestino · Dec 4, 2008

low yields

aha maybe tis not the low humidity that affects my yield. is there anybody out there getting killer yields with an RH of less than 45%?

adam · Dec 4, 2008

i have the opposite promblem and have to run a dehumidifier at 40%. lost a crop once to pm wont let it happen again:rain

Zoolander · Dec 4, 2008

I've had my RH at 30 % for flower and yield was great

ukcheesefiend · Dec 4, 2008

In low humidity (dry air) Leaves form narrower to reduce transpiration (natural evaporation), Leaves will be broader in a higher humidity space, increasing leaf surface area and trichomes, and so weight of manicured bud.

I always believed that the battle is having as high a humidity as possible, making the leaves breath as efficiently as possible, too high will cause mold issues though.

ukcheesefiend · Dec 4, 2008

You will lose moisture if the room is too hot, increasing your ventilation may increase your humidity, as cooler air holds more moisture.

If temperature isnt a concern then keep piling open containers of water into the room.:smoke

leadplant · Dec 4, 2008

In general, plants love humidity but they can do OK in low humidity too provided that they are healthy and past the seedling stage. During times of plant stress like botched transplanting and other grower screwups, it may be advantageous to raise your humidity, especially if its below 40%.

The ultrasonics are the best and quickest. Dont get a bigger unit. You must seal up the room you are trying to humidify really good or the humidity will escape to less humid areas. That is for sure the reason it doesnt seem to be working for you.

Stackin Paper · Dec 4, 2008

ukcheesefiend said:
You will lose moisture if the room is too hot, increasing your ventilation may increase your humidity, as cooler air holds more moisture.

If temperature isnt a concern then keep piling open containers of water into the room.:smoke

I've found buckets of water in the room don't help, maybe a wet towel hanging in there will be a better way to raise RH.

satty · Dec 4, 2008

I had the very same problem when i grew out some fantastic S.T. X Haze X S.T. My humidity was at 26%
and my buds were very airy and at the time it was -23C.
Tough growing situations for sure.
:sweating:

Finalopagus · Dec 5, 2008

ukcheesefiend said:
...as cooler air holds more moisture....

Not true.
We gotta X-plain that some more...

"Because moisture (water vapor) is part of air (mainly nitrogen and oxygen, with other trace gases including water vapor), I hesitate to say that “air” has any temperature-dependent “capacity” or ability to “hold” water vapor. What I can say is that water molecules are constantly changing phases (solid, liquid and gas) and that the rate of change is temperature dependent (there are other factors involved as well). When there is more energy available (higher temperature), there is a net evaporation (more molecules evaporate than condense). When temperature decreases, there is a net condensation.

So in the case of cloud formation, it isn’t that rising air cools and has less “holding capacity” for moisture, but rather that in a colder environment, there is net condensation, allowing for the growth of cloud droplets or even ice crystals."
this dude said it

On topic 'tino I don't think humidity is your culprit. Please take a picture of a leaf and post it...:nerd

clandestino · Dec 8, 2008

low humidity causing low yield?

hey thanx for all the replies i will indeed try and post some pix soon. the temperature in the room occasionally
reaches 28c so i am busy trying to increase ventilation to get it down to 25c on average. interesting to see that zoo has had good yields in low humidity. my previous grow was in a humid sub tropcal environment and i struggled to keep the RH down to 70% i had a lot of hassles with bud mould but i had two harvests that werent affected by it at all in the beginning. the first harvest was 2.1kg and the second 2.3kg if you consider that the light source was was four 400w hps then it was really quite high i all the while suspected that these bountiful harvests were the result of the high humidity! time will tell!

julsbagell · Dec 18, 2008

Heat affects yield, I wish I could keep my humidity at 30 percent in flower its got to be something else.

clandestino · Jan 22, 2009

low humidity not the culprit

just to conclude: it seems that my reduced yields were from the ph of my organic tea being too low. i have now gone back to using bio bloom instead and everything is looking great... thanx for all the advice y'all!

STR8EDJ · Dec 15, 2019

clandestino said:
running 9 600w lights in my flowering room and the humidity is dropping to 28% at times with terrible effects on my yields i tried using an ultrasonic humidifier but it only raised it by 2%. does anybody know of a more industrial cost effective way to raise humidity. i am considering greenhouse misters at the moment but worried it might affect my electrics. anybody out there with similar problems? help help help

CO2 burner will put off humidity. But also heat.
evaporation coolers work very well.
Used in most greenhouse to control your VPD. You want a VPD between 5-10. To be safe. But if you can dial it in to a little tighter it’s better.7-8

Smokecorleone415 · Jul 15, 2020

45% humidity is ideal for flower,if you start playing in the 50’s-60’s you run the risk of powder mildew and mold

clandestino said:
low yields

aha maybe tis not the low humidity that affects my yield. is there anybody out there getting killer yields with an RH of less than 45%?

Mdlroad55 · Mar 3, 2021

ukcheesefiend said:
You will lose moisture if the room is too hot, increasing your ventilation may increase your humidity, as cooler air holds more moisture.

If temperature isnt a concern then keep piling open containers of water into the room.:smoke

low humidity

low humidity

clandestino

Stackin Paper

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Finalopagus

clandestino

adam

Zoolander

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ukcheesefiend

ukcheesefiend

leadplant

Stackin Paper

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satty

Finalopagus

clandestino

julsbagell

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clandestino

STR8EDJ

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Mdlroad55

low humidity

low humidity

clandestino

Stackin Paper

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Finalopagus

clandestino

adam

Zoolander

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ukcheesefiend

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leadplant

Stackin Paper

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satty

Finalopagus

clandestino

julsbagell

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clandestino

STR8EDJ

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