Grow Room Pulse Labs Tester Group

[wwwillie]

PEMDAS

Ah yes, the high school version of my dear aunt sally, once you get that far that is, I mean exponents... Geez Louise!

The ability for users to self calibrate would solve this problem, but could possibly lead to others.

I understand the need to calibrate, but not how a correctly calibrated to Rh would help or hinder, I mean correct calibration would obviously help as in a sharp knife cuts better...

 

[Simplicio]

Ah yes, the high school version of my dear aunt sally, once you get that far that is, I mean exponents... Geez Louise!
I understand the need to calibrate, but not how a correctly calibrated to Rh would help or hinder, I mean correct calibration would obviously help as in a sharp knife cuts better...

Pulse's VPD calculation is thrown off by wrong RH or temp, and some of us use VPD extensively.
The alternative is to mentally correct Pulse readings for temp and humidity, then consult a VPD chart.
Pulse saves me several minutes each tent check, because I don't need to take 4 temp readings, 4 RH readings, average them, correct for difference between canopy and leaf temps, and finally compute VPD, and hope it's in range.

 

[wwwillie]

Pulse's VPD calculation is thrown off by wrong RH or temp, and some of us use VPD extensively.
The alternative is to mentally correct Pulse readings for temp and humidity, then consult a VPD chart.
Pulse saves me several minutes each tent check, because I don't need to take 4 temp readings, 4 RH readings, average them, correct for difference between canopy and leaf temps, and finally compute VPD, and hope it's in range.

Got it, thanks. That would be my take too but somehow I was reading something else into your comment. I calibrate all my Rh meters that I use for curing with the Boveda set-up, cheap and close enough. I am sure the Pulse will allow us to do that too. Like you said we rely on it so to be able to calibrate is essential.

 

[Mañ'O'Green]

VPD is an exacting science. Growing our cannabis at home - well not so much. I think that this is an amazing tool that gets us closer than not having it. If I were running a large scale commercial grow I would be working tighter tolerances. I grew good crops before I ever heard of VPD.

Here is a marked up chart with fahrenheit scratched in for all of us USA thinkers:

 

[Clix]

I have some snaps of my day temps vs my lights out temps. I finally found a system to keep the room cooler lol. I have been struggling with temps lately with a new lighting system I'm now getting the hang of.

Day

Night

 

[Clix]

Some pics of the garden as well.

 

[okPeet]

I consider the ability to easily calibrate by us users as an essential feature.

Definitely coming soon. In the meantime, just send me a message and we'll do a calibration remotely.

 

[okPeet]

Guys, I need some help understanding some aspects of VPD,.. I found a good article and posted it in the reference section.... what's jamming me up are the damn charts! the values are waaaaay different in the "general"? type charts like this-->



.... vs. the ones in the article, that state specific temp differences between the air and the leaves-->


Any idea this is about? What's your Pulse using for a scale? Seems it's close to these, not the non-specific ones....

The first one appears to have units in hPa (https://www.alchimiaweb.com/blogen/vapor-pressure-deficit-cannabis-cultivation/)
The other two have units in kPa. 10 hPa = 1 kPa.

Not sure how to account for leaf temp differences, that's a good question. Lmk if anyone comes up with a good answer

 

[Waira]

thanks Peet! I backtracked that graph and found out just that,......... as for the leaf temp's, maybe just have to pick ones that are well exposed but not the most, average something out, and go with it.... the only temp specific charts I found are the 1C and 2C,... It bugs me that they don't agree at all with the hPa graph- --- say, 25C and 70%RH... hPa is 9.5 (0.95kPa); 2C graph is 0.59, 1C 0.76,....

 

[Waira]

@okPeet -- I was editing just now,...