LED VPD chart

Hey folks

I saw someone post and adjusted VPD chart for growing with LEDs. Searched the forum to no avail and my google-fu wasn't good enough.

Anyone got the image for me?

Ill do you one even better:
http://opennlabs.com/vpd/VPD_calculator.php

This one you can set it for +- degrees in C, in order to adjust for leaftemp being higher or lower than ambient.
Remember that VPD is not the bible but when you get environment related problems with the grow it can tell you in which way to go.

Rocket Soul said:

Ill do you one even better:
http://opennlabs.com/vpd/VPD_calculator.php

This one you can set it for +- degrees in C, in order to adjust for leaftemp being higher or lower than ambient.
Remember that VPD is not the bible but when you get environment related problems with the grow it can tell you in which way to go.

Click to expand...

That's (almost) super helpful, thanks!! But it opens another can of worms, I don't have an IR thermometer, what would be the expected temp below ambient for an average QB setup?

DonnyDee said:

That's (almost) super helpful, thanks!! But it opens another can of worms, I don't have an IR thermometer, what would be the expected temp below ambient for an average QB setup?

Click to expand...

It kinda depends on how much light you give them and what spectrum, id shoot for somewhere between -1 and -2 but primarily look at your plants for a happy praying stance.

Rocket Soul said:

It kinda depends on how much light you give them and what spectrum, id shoot for somewhere between -1 and -2 but primarily look at your plants for a happy praying stance.

Click to expand...

3500k 90cri at around 400uMol

Thanks, never really considered that there was a sweetspot, all of a sudden DLI makes much more sense.

-2 id say, but let your plants do the talking

DonnyDee said:

3500k 90cri at around 400uMol

Thanks, never really considered that there was a sweetspot, all of a sudden DLI makes much more sense.

Click to expand...

Its not really about DLI, its more about more light, hotter leafs. Id also encourage to try with -1. Almost as a general advice for growing led if you come from a HID background, use more heat rather than less. It boosts the metabolic rate of your plant. They will be happy up to 30°C. But you need to have really good control of your humdity.

Would it be easier to grow in low DLI or low VPD. Kinda seems important, DLI....

After reading around and buying in for a while, vpd again seems strain dependant and climate dependent, therefore, just more shots in the dark imho. Even vpd itself seems dubious....at least how it is currently defined.

DonnyDee said:

That's (almost) super helpful, thanks!! But it opens another can of worms, I don't have an IR thermometer,

Click to expand...

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