VPD Explained
- Thread starter NotAquaMan
- Start date
NotAquaMan
In Bloom
Yeah I can imagine. Unfortunately the ideal environment for cannabis is not so much as comfortable for us. I personally would avoid a humidifier in the tent. Unless its a big tent but even then the humid air is just being pulled out and dry air being sucked in. If you can tolerate 60% RH in the room would be better for the plant but even 50% will be fine
NotAquaMan
In Bloom
absolutely
cool, will check it out later. Thanks for your suggestion, I'll see how it compares to what I have now. Just checked the tent and it's 84F/56% RH.
How would one predictively manage vpd?
I just typed a whole bunch of stuff and crappy internet caused me lose connection.
I just typed a whole bunch of stuff and crappy internet caused me lose connection.
Spectrum?
How does vpd vary through the day in nature and is this ideal?
Is there a prefered way to adjust vpd with temp and humidity? Which to use depending on if you want vpd to go up or down? Aside from avoiding modifying the growing method by causing something like a nighttime temperature inversion.
Posting now, continuing thought.
How does vpd vary through the day in nature and is this ideal?
Is there a prefered way to adjust vpd with temp and humidity? Which to use depending on if you want vpd to go up or down? Aside from avoiding modifying the growing method by causing something like a nighttime temperature inversion.
Posting now, continuing thought.
The primary difficulty I have is accurately and precisely determining the parameters. How precise and accurateare the laser temp pens, are they better than consumer grade hygrometers? Just looking at the sources of error and where effort is most efficient. I don't disagree with vpd so I dont want to battle it, rather work with it.
Jewels
Tilts at Tables
Seasonal, Diurnal and Vertical Variation of Chlorophyll Fluorescence on Phyllostachys humilis in Ireland
In recent years, temperate bamboo species have been introduced in Europe not only as an ornamental plant, but also as a new biomass crop. To measure adaptation stress of bamboo to the climate of Western Europe, chlorophyll fluorescence was measured on ...
www.ncbi.nlm.nih.gov
Put your thinking cap on,,,
"An important interaction was observed between light and air temperature, as the interaction amplifies the effect of these two factors. This means that the negative effect of increased light intensity on Fv/Fm is even stronger at decreasing air temperatures, whereas at increasing air temperatures, the negative effect of increasing light intensity will be less"
I was reading this, investigating the events and implications of sunrise.
Good stuff.
Jewels
Tilts at Tables
Infrared Emissivity Table
NotAquaMan
In Bloom
I usually try to run my plants as warm as they will tolerate. Leaf temps can be vastly different in the varying conditions we all run so it's a much more accurate way to see where the plants are in terms of temps. It's absolutely key to VPD.
In terms of outdoor changes we can't compare to indoor. Light intensity varies, humidity, temps etc. None are constant so we in no way shape or form should compare these with indoor.
In terms of outdoor changes we can't compare to indoor. Light intensity varies, humidity, temps etc. None are constant so we in no way shape or form should compare these with indoor.
NotAquaMan
In Bloom
I always run the highest temp my plants will allow and adjust the humidity according to VPD using leafs temps in the equation
Would it not make sense that plants have evolved a means of dealing with this? They don't have heaters and dehumidifiers. They do have stoma that close down when exposed to uv. In proportion to visible light the ratio of uv is higher before sunrise and after sunset....thinking cap on.Seasonal, Diurnal and Vertical Variation of Chlorophyll Fluorescence on Phyllostachys humilis in Ireland
In recent years, temperate bamboo species have been introduced in Europe not only as an ornamental plant, but also as a new biomass crop. To measure adaptation stress of bamboo to the climate of Western Europe, chlorophyll fluorescence was measured on ...
Put your thinking cap on,,,
"An important interaction was observed between light and air temperature, as the interaction amplifies the effect of these two factors. This means that the negative effect of increased light intensity on Fv/Fm is even stronger at decreasing air temperatures, whereas at increasing air temperatures, the negative effect of increasing light intensity will be less"
I was reading this, investigating the events and implications of sunrise.
Good stuff.
Jewels
Tilts at Tables
Ripping along last night.
4 hours into day cycle.
I used an online vpd calc. It says things are tits.
I downloaded an android app,,, it says - no good.
Ambient, air, and lower foliage temp = 34C
Canopy temp = 30 c
RH =%64
Should be good ? How do you guys make calculations ?
4 hours into day cycle.
I used an online vpd calc. It says things are tits.
I downloaded an android app,,, it says - no good.
Ambient, air, and lower foliage temp = 34C
Canopy temp = 30 c
RH =%64
Should be good ? How do you guys make calculations ?
Jewels
Tilts at Tables
Thanks @spyralout.
In flower.
Y axis highlighted correctly @ 34C.
Leaf diff is correct @ -4c
My humidity was 64
Puts me @ .8 on that chart. Puts me a little rich. Like buddyrotty territory- no ?
By that chart @ 34 I should be shooting @ 54 %?
In flower.
Y axis highlighted correctly @ 34C.
Leaf diff is correct @ -4c
My humidity was 64
Puts me @ .8 on that chart. Puts me a little rich. Like buddyrotty territory- no ?
By that chart @ 34 I should be shooting @ 54 %?
How did I miss this? Sweet Jebus @NotAquaMan
NotAquaMan
In Bloom
I swear by VPD bro, figured I would make a thread since there is such bad info on it out there. All these charts floating around without taking leaf temps into account so ppl run to high of humidity and say VPD doesn't work. When you take leaf temps into account it's an absolute game changer in terms of happy, healthy and faster growing plants.
This little IR temp gun I just got is going to be a gamechanger for me... Thank you for taking the time to write this out for us.
Yea, that's how I read it as well. I think pounding a buncha air in there should help with avoiding bud rot. Every time I ever got it was because there wasn't enough movement in the air.
