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VPD: Ideal temperature/relative humidity

Douglas.Curtis

Autistic Diplomat in Training
in hydro the roots are spoiled and friggin huge so vpd is less of an issue the plants can easily drink what they need and have the energy there to do it.
In my experience, I completely disagree. Soil or hydro, transpiration is driven by VPD and without it you end up with weak, slow growing plants.
 

beta

Active member
Veteran
Hydro is obviously a way different kettle of fish to soil in a lot of ways.. imo the roots dont get stressed the same way as they can in soil from sudden drying due to the way ph swings salt availability and osmosis/transpiration stress essentially effects the roots.. in hydro the roots are spoiled and friggin huge so vpd is less of an issue the plants can easily drink what they need and have the energy there to do it.


This simply isn't true. VPD is about transpiration, which is required for photosynthesis. If VPD is out of range, transpiration slows and photosynthesis slows. It does not matter how wet the roots are if the stomata are closed because it's too dry in the room.
 

Douglas.Curtis

Autistic Diplomat in Training
I've ran a spot on VDP run and my recent run with out my ultrasonic fogger with a rh of 50 thru veg. Growth in the 50% veg room suffered drastically. About 1' shorted than my VDP matched room. Went back to running my ultrasonic fogger from now on.
This is exactly why I veg longer and use low temp, dry air. Screw that stretched out bro science 'Bigger is Better' with cannabis, old school bullshit. You're growing stretched out inferior cannabis.

Old school is tropical environment, mass plant matter growing for yield. New school is "minimal plant matter, maximum terp/resin density."

When it smokes so smooth and soft it's difficult to tell you filled your lungs, you'll be blown away by how solid the flavor and aroma is on the exhale.

Everyone who has experienced the difference knows the truth. :)

Yeah, I'm not a fan of the prevailing bro science driving the low cannabis quality brigade today.
(Edit: My apologies, this is a very touchy subject for me. It's awful to run out of my own quality cannabis, knowing I have zero access right now to others who grow as good or better quality. If I had plenty of growers pumping out the quality I'm talking about, I wouldn't be as vocal about this as I am. What standard is producing the quality I'm unable to consume with joy? Tropical.)


Exactly!

I bet you any money that a significant amount of these calcium/Nitrogen lock out issues people get is the whole "grow at 40% RH to avoid PM problems" it's absolute bro science..


15+ years of <30RH grows and no mold issues says different. The issue is people drop the humidity and not the temps. ;)
 

Bobby Boucher

Active member
The idea that idea that humid rooms produce inferior cannabis is total phooey, homie.

I've seen buds that were grown at 80% and turbo-dried at 30% that were 200% terps by volume. Trust and believe. Not saying y'all should grow like this and dry like that. Just callin it like I see it.
 
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