Z
z-ro
Ive never read so much misinformation in my life.
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H
Huckster79
I've read several journal writings on this and though get lost in math equations the science center is there to indicate a bit higher humidity that the old rule of thumb may not be quackery
Obviously the old rules of thumb work... but how boring would life be if we didn't trust to expand upon them and make them better
Obviously the old rules of thumb work... but how boring would life be if we didn't trust to expand upon them and make them better
Snook
Still Learning
your name is zero and that is what you have provided here.
what is you dilemma? enlighten us with your wisdom.
Then there is Gry..High Gry.. he loves this site, so do I.
O
OG Tree Grower
Just did an experiment for my own sake.
I tied a branch 2" away from my bulb, 415f, waited since yesterday
Went there today and got this pict for you.
A totally bleached leaf, 2" away from 415f, still holding a leaf temp of 82f in a room that's 86.
Not sure why this stuff is so hard to grasp or swallow for some people.
Besides I'm sure if I was wrong enough people would have been all over me with there Picts of higher leaf temps than air but there arnt any. Cause it can't happen.
Z-RO. Not sure what part u were referring too but I've been running proper vpd rooms for over 2 decades. It's nothing new or secret. Your plants grow faster and bigger every day due to the fact that they can use all of there energy for growing rather than transpiring .
I tied a branch 2" away from my bulb, 415f, waited since yesterday
Went there today and got this pict for you.
A totally bleached leaf, 2" away from 415f, still holding a leaf temp of 82f in a room that's 86.
Not sure why this stuff is so hard to grasp or swallow for some people.
Besides I'm sure if I was wrong enough people would have been all over me with there Picts of higher leaf temps than air but there arnt any. Cause it can't happen.
Z-RO. Not sure what part u were referring too but I've been running proper vpd rooms for over 2 decades. It's nothing new or secret. Your plants grow faster and bigger every day due to the fact that they can use all of there energy for growing rather than transpiring .
Attachments
O
OG Tree Grower
CoCoSativas
Active member
Some take heat better than others. Many sativa high heat dosent do shit but it can effect indica in MANY ways.
MileHighGlass
Senior Member
If you continue to read about radiant heat you can also see that leaf color, leaf thickness, water in the root zone, and humidity will effect the outcome dramatically.
It's all very interesting though. I'm not on here saying anyone is "right" or "wrong", or saying I can't believe someone can't "grasp" this or that.
That is just someone trying to prove they know more than others, and discounting what the others have shown.
It's all very interesting though. I'm not on here saying anyone is "right" or "wrong", or saying I can't believe someone can't "grasp" this or that.
That is just someone trying to prove they know more than others, and discounting what the others have shown.
O
OG Tree Grower
No it's actually someone speaking from experince, not quoting articals from 1965. I have no need to prove anything. But threads like this are exactly why good members quit posting. Good day gents
MileHighGlass
Senior Member
You are saying your "experience" trumps others "experience."
I'm assuming you don't "believe" in gravity because it was first theorized in the 1600's?
This is getting funny now.
O
OG Tree Grower
Your assumptions are what's funny, and don't put words in my mouth. I'm done here.
MileHighGlass
Senior Member
A childrens experiment from a botnaical garden outlines why leaves can heat up in low humidity enviroments
http://www.huntington.org/uploadedFiles/Files/PDFs/BGRPleafcolor.pdf
It talks about leaf shape, size, color, and humidity being factors. Also you can add time of day as the stomata can be open or close for certain amounts of time thus helping to cool the plants.
An exert fro those that don't want to read.
"Leaf color as a reflection of the environment: In dry, hot, sunny environments,
water is often a limiting factor so leaves from these environments may exhibit
special adaptations that retard water loss. For example, the leaves may be covered
with a thick covering of hairs that trap moisture that may be escaping from
the leaf during the process of transpiration. The presence of this moisture on the
hairs around the stomata can slow down the transpiration process by increasing
the relative humidity near the leaf surface.
Overheating can also be a problem for many plants in dry, hot environments.
Since only about 3% of incoming radiant energy is utilized in photosynthesis by
plants in full sun, the rest of the absorbed radiant energy may be converted to
heat, essentially cooking the leaves. Heat loss is possible when the plant transpires
(but adequate water is a necessity for this process), as well as by physical
processes that involve carrying heat away from a plant surface (for instance, toothed
leaves may increase air turbulence, creating little breezes that carry away some of
the heat). In addition, plants have adaptations that prevent heat absorption in the
first place, such as smaller leaf surfaces and light coverings on the surface of the
leaves. Studies have shown leaves covered with light colored wax or hairs may
absorb less than 50% of the radiant energy of dark-colored leaves."
Interesting info. I am always happy to reread things I read many years ago. It makes you realize you forget way more than you will ever learn.
http://www.huntington.org/uploadedFiles/Files/PDFs/BGRPleafcolor.pdf
It talks about leaf shape, size, color, and humidity being factors. Also you can add time of day as the stomata can be open or close for certain amounts of time thus helping to cool the plants.
An exert fro those that don't want to read.
"Leaf color as a reflection of the environment: In dry, hot, sunny environments,
water is often a limiting factor so leaves from these environments may exhibit
special adaptations that retard water loss. For example, the leaves may be covered
with a thick covering of hairs that trap moisture that may be escaping from
the leaf during the process of transpiration. The presence of this moisture on the
hairs around the stomata can slow down the transpiration process by increasing
the relative humidity near the leaf surface.
Overheating can also be a problem for many plants in dry, hot environments.
Since only about 3% of incoming radiant energy is utilized in photosynthesis by
plants in full sun, the rest of the absorbed radiant energy may be converted to
heat, essentially cooking the leaves. Heat loss is possible when the plant transpires
(but adequate water is a necessity for this process), as well as by physical
processes that involve carrying heat away from a plant surface (for instance, toothed
leaves may increase air turbulence, creating little breezes that carry away some of
the heat). In addition, plants have adaptations that prevent heat absorption in the
first place, such as smaller leaf surfaces and light coverings on the surface of the
leaves. Studies have shown leaves covered with light colored wax or hairs may
absorb less than 50% of the radiant energy of dark-colored leaves."
Interesting info. I am always happy to reread things I read many years ago. It makes you realize you forget way more than you will ever learn.
I understand radiant vs convective. Earlier when I posted science that states leaf temps almost always cooler than air, at noon, world wide, do you not think that the sun being involved brings radiant energy to the table? In fact, given the vacuum of space IO believe all heat the earth receives is radiant.
So, if its true for the sun's radiance seems it would also be true for HID. The later also bring convective heat due to air and proximity.
The bottom line is industry since says you can tell when a plant needs watering based on the delta between leaf and air. As the delta decreases moisture stress is evident. This could be caused by freakish high humidity, but can also be caused by low ala VPD.
I run a 600w air cooled in a 2x2 closet. I bring in cool air from outside at night using a 6" vortex. Very low humidity here in so cal. I felt I could see VPD, and started running a ultrasonic humidifier at lights on. I find there is no change in the humidity readings even with the humidifier running given all the fresh air coming in. I run it anyways as cannot hurt.
In summer I can have canopy at 90+ (shaded thermometer) with 20% humidity and that does cause stress imo. They still grow, but may throw a swamp cooler in the room during summer to try and get humidity up a bit more given I have to rely on passive air.
Regards
A childrens experiment from a botnaical garden outlines why leaves can heat up in low humidity enviroments
http://www.huntington.org/uploadedFiles/Files/PDFs/BGRPleafcolor.pdf
It talks about leaf shape, size, color, and humidity being factors. Also you can add time of day as the stomata can be open or close for certain amounts of time thus helping to cool the plants.
An exert fro those that don't want to read.
"Leaf color as a reflection of the environment: In dry, hot, sunny environments,
water is often a limiting factor so leaves from these environments may exhibit
special adaptations that retard water loss. For example, the leaves may be covered
with a thick covering of hairs that trap moisture that may be escaping from
the leaf during the process of transpiration. The presence of this moisture on the
hairs around the stomata can slow down the transpiration process by increasing
the relative humidity near the leaf surface.
Overheating can also be a problem for many plants in dry, hot environments.
Since only about 3% of incoming radiant energy is utilized in photosynthesis by
plants in full sun, the rest of the absorbed radiant energy may be converted to
heat, essentially cooking the leaves. Heat loss is possible when the plant transpires
(but adequate water is a necessity for this process), as well as by physical
processes that involve carrying heat away from a plant surface (for instance, toothed
leaves may increase air turbulence, creating little breezes that carry away some of
the heat). In addition, plants have adaptations that prevent heat absorption in the
first place, such as smaller leaf surfaces and light coverings on the surface of the
leaves. Studies have shown leaves covered with light colored wax or hairs may
absorb less than 50% of the radiant energy of dark-colored leaves."
Interesting info. I am always happy to reread things I read many years ago. It makes you realize you forget way more than you will ever learn.
I read the excerpt and seems to indicate that leaves cool by transpiration, and that adequate water is needed for that to occur. In the absence of adequate water plants make adaptations. Great.
It still seems that providing sufficient moisture would be ideal rather than relying on some evolution. Due you want your cannabis to mutate into hairy leaves that help protect the leaf in your low humidity? Why not give some water and let that plant energy go into buds?
BTW, your grow looked great. Maybe it could be better. you mentioned not seeing a difference when you ran humidifiers. I did not catch if you ever measured an actual increase in humidity at the time, and if so, from what (baseline) to what?
As I noted, I run a little cool mist humidity and it does not register on my gauges given the air flow into my closet. I am thinking of adding a swamp cooler.
Regards
MileHighGlass
Senior Member
At first I ran a swamp cooler, and then I moved and I could only use the foggers. My humidity did increase, but I can't remember how much as this was 2 years ago. It was significant with the swamp cooler, not so much with the foggers.
I hooked the swamp cooler up to my intake, and just ran the pump on the cooler. My inline fan in my tent would pull moist air through the cooler, and that air would enter the tent. It worked well, but I did not see much for yield gains, health, etc..
The biggest difference I have seen in plant health, yields, and vigor is using a notill soil setup. My yields are up, health is the best it's ever been, and vigor is so much better than before on older strains.
After rereading much of what I read a few years ago I can't say that I will use a swamp cooler or foggers again.
Hello Elmer,
The point of it being, the of halt resistance through the evisceration of our educational system.
I thought the reference was if anything a bit too clear. It was not my intent to insult those involved with the thread, but rather to bemoan the destruction of a once decent educational system.
The point of it being, the of halt resistance through the evisceration of our educational system.
I thought the reference was if anything a bit too clear. It was not my intent to insult those involved with the thread, but rather to bemoan the destruction of a once decent educational system.
