Chasing VPD with LED

So I've been focusing on VPD for this grow, and things seem to be working pretty well so far.

https://www.rollitup.org/t/2nd-small-tent-soil-quantum-boards-blue-uv.990841/

Growth has been vigorous, leaves praying etc. The only issues I've seen are some of the older leaves twisting and curling, and their tips turn downward. Moisture does accumulate when two leaves touch. I've been pruning fairly heavily because it gets so bushy.

My ambient temps are usually around 83F day 77F night, with my RH set to 77%. My question is concerning leaf surface temperature, which are typically 74F. If I input -10 leaf surface temperature to a VPD calculator (pulse labs) the "sweet spot" for humidity is 50%. Seeing as how my current growth is doing well I'm hesitant to make such a drastic change.

I'm using LED lighting, which is why I'm running higher temps. The calculator doesn't care about light source. I wonder if the calculation isn't modeled around HPS to account for higher leaf temps, although since there is an input for LST that doesn't make sense.

Some details in case you don't want to follow the link to my journal:
Day 28 veg, sativa leaning hybrid
Small tent, 2X2.5'
Soil grow FoxFarm Ocean Forest 10gal fabric
QB288v2 X2 with red/blue supplement plus UV
Extraction fan runs 45sec every 8mins to maintain temp/RH

Interesting question .RootDown and legit LED btw! Today is the best I've done chasing VPD but its hard for me to maintain humidity when the temp starts to rise which in turn causes my fan to go into overdrive...it's a constant battle haha

I'm curious to know if your tent is steamy at that extraction rate? Could you breathe properly if you put your head in the tent?

I grow in soil and use the biobizz line and from my understanding of the chart, if you're slightly on the right hand side of the "green zone" it promotes more drinking from the roots which should be beneficial based on how we're feeding with nutes.

doogledore said:

if your tent is steamy

Click to expand...

Yes, it's pretty thick! I can breathe, but it's like being in a greenhouse for sure. When I tend to the garden I keep the closet door closed to maintain the environment as best as I can, and upon exit the air conditioning feels great!

I've had to mess around with the extraction rate to maintain the levels. The fans seem to suck out the humidity much faster than the heat for sure, but the humidifier builds it back fairly quickly.

Feeling cute.
Might delete later.