HLG 600 RSPEC, heat?

[Star Dog]

Leaf temps are 3-5f lower than ambient using LED due to transpiration. LEDs have little IR to hear up leaf surface directly

82f air temp, 78f leaf temp right now in my tent

I don't think its possible to have a leaf temp higher than ambient under an LED, not a live leaf anyways

What do you think I'm making it up?
It's a fact regardless what you think, when I say something it's because it's happened.

I can tell you right now my leaf and ambient are the same.

 

[Billy the Mountain]

when the weather was cold the leaf temp under a tsl was greater than the ambient, I've not had leds that long but ime it's not a given the leafs are 2c cooler.

What do you think I'm making it up?
It's a fact regardless what you think, when I say something it's because it's happened.

I can tell you right now my leaf and ambient are the same.

I still don't think its possible for a leaf surface temp to be higher than ambient under an LED (at a normal growing height). Leaf surface temp should be a few degrees lower than ambient due to transpiration. If its not, something's wrong.

 

[Star Dog]

I still don't think its possible for a leaf surface temp to be higher than ambient under an LED (at a normal growing height). Leaf surface temp should be a few degrees lower than ambient due to transpiration. If its not, something's wrong.

VPD with a range of leaf temps above and below ambient?

VPD Calculator by Everest Fernandez

 

[Billy the Mountain]

HPS lights raise leaf temps above ambient due to lots of IR output and have a positive value
LED lights will have a negative value

 

[Star Dog]

Whatever, the ir thermometer doesn't lie.

 

[grotbags]

IR is in most leds these days

far red is in some... IR is in none...

 

[grotbags]

Whatever, the ir thermometer doesn't lie.

is your IR gun a decent one?, does it allow you to set emissivity?.
i have a cheap one and my leaves are approx -2 to -4 lower than ambient but i dont really trust its accurate, but dont fancy buying a decent fluke one...

 

[Star Dog]

is your IR gun a decent one?, does it allow you to set emissivity?.
i have a cheap one and my leaves are approx -2 to -4 lower than ambient but i dont really trust its accurate, but dont fancy buying a decent fluke one...

Emisive sensitivity I'm not sure about but it's a quality thermometer irc the model but it's a leak brand.
I've also a cheap crappy one that reads 3/4c under.

The light in question (Tsl2000) does have ir I assumed that's where the temperature was coming from at 20"

 

[Orb]

No Mars only use 'far red' 730nm diodes as do almost all manufacturers right now, I haven't seen one plug and light fixture with any true 'IR' 780nm+ diodes included, they're available on stars and some diy strips now but have yet to see anyone use any

 

[Star Dog]

No Mars only use 'far red' 730nm diodes as do almost all manufacturers right now, I haven't seen one plug and light fixture with any true 'IR' 780nm+ diodes included, they're available on stars and some diy strips now but have yet to see anyone use any

Your sure?

 

[Orb]

Yes it says ir 730nm which is fine for them to say, 730nm is also known as far red this falls in the region between 700-750nm and we know a lot of its properties already

When I say true IR
IR is categorized as IR-A (780 nm-1.4 µm), IR-B (1.4-3 µm) and IR-C, also known as far-IR (3 µm-1 mm)

So yes I'm sure it has 730nm chips whether you categorise it as far red or ir is your choice

 

[Star Dog]

I don't categorise them it says they're ir I take it at face value I'm not a lighting expert.

 

[Star Dog]

Leaf temps are 3-5f lower than ambient using LED due to transpiration. LEDs have little IR to hear up leaf surface directly

82f air temp, 78f leaf temp right now in my tent

I don't think its possible to have a leaf temp higher than ambient under an LED, not a live leaf anyways

Whatever but it doesn't change the facts...
thermometer left on the canopy.

Hanging on the wall.

Leaf temp.

Hot spot.

Controller.

The bottom reading is the canopy temperature.

Sincerest apologies to op