L.E.D. Argument Thread For Dummies:)

[Aqua Man]

Tomatoes 0.9-1.2 again different than cannabis

 

[Aqua Man]

of course. Higher temp higher transpiration more water and nutrients taken up.

Ok so we agree nutrient uptake affects plant health and growth?

 

[MIMedGrower]

Just Google orchids kpa.

Ok here they show evidence of higher yields with fruits and veggies at .8 kpa over .5.

https://staugorchidsociety.org/PDF/HumidityandVaporPressureDeficitbySueBottom.pdf

But why is cannabis not affected for yield?

 

[MIMedGrower]

Tomatoes 0.9-1.2 again different than cannabis

i am seeing this now. So most everyone is just using the vpd chart without knowing the proper kpa to teach and not having the correct parameters metered?

And just to notice .9 to 1.2 is a big range.

 

[MIMedGrower]

Tomatoes 0.9-1.2 again different than cannabis

what is cannabis range supposed to be?

 

[Aqua Man]

More non cannabis related studies on stress caused by humidity and gas exchange.

Stomatal responses to changes in humidity in plants growing in the desert - PubMed

The stomata of plants growing in the Negev Desert, namely the stomata of the mesomorphic leaves of Prunus armeniaca, the xeromorphic stems of Hammada scoparia, and the succulent leaves of Zygophyllum dumosum, respond to changes in air humidity. Under dry air conditions diffusion resistance...

pubmed.ncbi.nlm.nih.gov

 

[Aqua Man]

i am seeing this now. So most everyone is just using the vpd chart without knowing the proper kpa to teach and not having the correct parameters metered?

And just to notice .9 to 1.2 is a big range.

100% that's why I made that post to explain how it should be used.

 

[Aqua Man]

what is cannabis range supposed to be?

It's all in my post.

 

[MIMedGrower]

It's all in my post.

i meant to ask where did you get it?

 

[Aqua Man]

Again it's not a hard rule just an ideal target and plants will do well even far outside of it.

 

[Aqua Man]

i meant to ask where did you get it?

I'd have to dig through the million studies but you will find those number in several places or very close too... worked for 25.5 hrs straight yesterday and had a few hrs sleep and back at work now so I'm a bit foggy and slow but I can dig em up for you prob Sunday if you like.

 

[Moshmen]

Can’t sleep and love to read you guys views and opininions I can’t help but through in my uneducated opinion/ question -
Can VPD be taped to the basic plant zones? I can’t grow the same flowers/ plants here in fla that I could I. Michigan - I believe it’s temp and humidity? Ie plant zones/climates - most out door plants have waxy leaves to help with rainfall and humidity and heat . Isn’t that a basically vpd ?
sorry to interrupt continue on ! Lol
Orchids do way better here than up there ! Lol

 

[MIMedGrower]

Can’t sleep and love to read you guys views and opininions I can’t help but through in my uneducated opinion/ question -
Can VPD be taped to the basic plant zones? I can’t grow the same flowers/ plants here in fla that I could I. Michigan - I believe it’s temp and humidity? Ie plant zones/climates - most out door plants have waxy leaves to help with rainfall and humidity and heat . Isn’t that a basically vpd ?
sorry to interrupt continue on ! Lol
Orchids do way better here than up there ! Lol

thats my point about the static chart.

But weed is much more adaptable than orchids.

 

[Aqua Man]

Honestly I'm with you on these charts they are out and out bullshit and each grow is different and lighting used has a lot to do with it.

 

[MIMedGrower]

I'd have to dig through the million studies but you will find those number in several places or very close too... worked for 25.5 hrs straight yesterday and had a few hrs sleep and back at work now so I'm a bit foggy and slow but I can dig em up for you prob Sunday if you like.

its ok. Just wondering how many different kpa ranges are being used for weed.

 

[MIMedGrower]

Honestly I'm with you on these charts they are out and out bullshit and each grow is different and lighting used has a lot to do with it.

Thats the source of my skepticism

 

[MIMedGrower]

Its great @Moshmen that we can wake up in the middle of the night while our loved ones sleep like normal people and have like minded folks to chat with. I spend some time with my plants and then start thinking about all this crap. Amazing hobby. Amazing.

 

[Aqua Man]

Can’t sleep and love to read you guys views and opininions I can’t help but through in my uneducated opinion/ question -
Can VPD be taped to the basic plant zones? I can’t grow the same flowers/ plants here in fla that I could I. Michigan - I believe it’s temp and humidity? Ie plant zones/climates - most out door plants have waxy leaves to help with rainfall and humidity and heat . Isn’t that a basically vpd ?
sorry to interrupt continue on ! Lol
Orchids do way better here than up there ! Lol

It can be part of the reason but as mimed pointed out the largest factor will be the temp and water stress especially outdoors. Most plants can deal with the dry air of they have adequate water. This is because they pull more water through in lower humidity and thus create more evaporative cooling at the leaves... this is why VPD really has to take leaf temp into account to truly be of value

 

[MIMedGrower]

It can be part of the reason but as mimed pointed out the largest factor will be the temp and water stress especially outdoors. Most plants can deal with the dry air of they have adequate water. This is because they pull more water through in lower humidity and thus create more evaporative cooling at the leaves... this is why VPD really has to take leaf temp into account to truly be of value

and plant type?!?!?!

 

[Aqua Man]

Thats the source of my skepticism

Nobody hates them more than I do... thats why I always link it when ppl post charts... they are the absolute opposite of what we should be shooting g for in most cases and far far to high on the humidity.