Ideal humidity for flowering?

HotKarl2

HotKarl2

Well-Known Member
The Hippy said:
I've considered getting one of these...anyone have any experience with steam units?

https://www.anden.com/products/model-865866/
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Fucking cool.
TheRealDman said:
The gold fields are ranges of ok (7.5), to optimal (10.5).

Do your plants pray towards the light? If so, chances are your VPD is on point.

Budrot indoors is a result of high humidity, with a lack of adequate air movement...IMO.
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All of which does not address the fact that we do not run rooms at 80-90F with 75-80% humidity right!!! That is obviously canopy humidity and it is affected if you have large colas too dense too close to one another! Yes you need air movement but if you don't have enough space between plants you get dead fields where bud rot grows.
 
HotKarl2

HotKarl2

Well-Known Member
HotKarl2 said:
Fucking cool.


All of which does not address the fact that we do not run rooms at 80-90F with 75-80% humidity right!!! That is obviously canopy humidity and it is affected if you have large colas too dense too close to one another! Yes you need air movement but if you don't have enough space between plants you get dead fields where bud rot grows.
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And what the heck kind of measuring device do you need to measure what the leaves experience as canopy humidity! I guess you can bury a humidistat in the canopy, a probe would be better though.
 
NGA

NGA

Well-Known Member
If your room sweets when lights go out you are running high humidity not good ,I don't own a humidity meter , I can tell by just walking in the room you ,sorta old school didn't have ph -rh pens back then
 
itsmehigh

itsmehigh

Well-Known Member
RH% needs to be 48% and higher for mould/mildew to live. At 30% the stomata will not fully open. So a range of 31%-48% is optimal. I find that later in flower a lower RH 35%-40% produces more trichome. As trichome are a defence mechanism for the plant, by slightly stressing the plant it will throw out more trichome. I personally set my RH to 45% veg/flower and at week 6 flower after my last prune I lower to 35%. The critical point is when your lights first turn off and the temp drops, that’s when dew will form on your leaves or bud. Catch 22 is that spider mites thrive in low RH.

Itsme.
 
HotKarl2

HotKarl2

Well-Known Member
TheRealDman said:
It’s a numeric calculation of VPD at that temp/humidity level. 7.5 being the minimal level for optimal transpiration. The chart may not be specifically designed for Cannabis, but it has proven to be extremely accurate for Cannabis.
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Leaves are undergoing a chemical transformation under the light, it is difficult to measure what the transpiration rate is "at the canopy" vs "below the canopy" etc. WTF kind of instrument does that I would like to know. I submit it would have to be some kind of photo-voltaic cell placed among the leaves interspersed to achieve a measurement of average lumination and other sensors to measure hydrologic humidity? I admit I am way out of my depth here.
 
itsmehigh

itsmehigh

Well-Known Member
HotKarl2 said:
Leaves are undergoing a chemical transformation under the light, it is difficult to measure what the transpiration rate is "at the canopy" vs "below the canopy" etc. WTF kind of instrument does that I would like to know. I submit it would have to be some kind of photo-voltaic cell placed among the leaves interspersed to achieve a measurement of average lumination and other sensors to measure hydrologic humidity? I admit I am way out of my depth here.
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There are so many variables, adding more terminology or tests is silly IMO. Good air flow, a low ambient dehumidification, and a hi/lo hydrostrat at or in the canopy is all you need to dial in your garden. Depending on the canopy size and density, it will most likely have its own micro climate. Having your hydostat on the wall or near your lights is a mistake, have it in the canopy and move it around to different spots to get an accurate reading. Keep It Simple Stoner.....

Itsme.
 
CalyxCrusher

CalyxCrusher

Well-Known Member
NGA said:
If your room sweets when lights go out you are running high humidity not good ,I don't own a humidity meter , I can tell by just walking in the room you ,sorta old school didn't have ph -rh pens back then
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Yep, too big a difference in lights on and lights off will do that. Room condensates
 
gwheels

gwheels

Well-Known Member
Air flow is everything to prevent PM. I just let mine run and they grow as they should. Summer time the humdity goes up this time of year the humidity is down. I am about 40 to 50% in flower right now but that will go 50 to 60% in the summer time. I do not run a huey but i will run a dehuey in the basement sometimes in the summer.
 
TheRealDman

TheRealDman

Well-Known Member
HotKarl2 said:
Leaves are undergoing a chemical transformation under the light, it is difficult to measure what the transpiration rate is "at the canopy" vs "below the canopy" etc. WTF kind of instrument does that I would like to know. I submit it would have to be some kind of photo-voltaic cell placed among the leaves interspersed to achieve a measurement of average lumination and other sensors to measure hydrologic humidity? I admit I am way out of my depth here.
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VPD is measured by the visual health of the plants, not by instruments. If the leaves on your plants are always reaching for the light, your VPD is on point.
 
TheRealDman

TheRealDman

Well-Known Member
Just google VPD + Cannabis...tons of info on the subject out there. If you just google VPD the 1st hit is Vancouver Police Department...lol! :D
 
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