HLG 600 RSPEC, heat?

Star Dog

Well-Known Member
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

Well-Known Member
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

Well-Known Member
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

Active Member
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

Well-Known Member
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?
s-l400 (1).jpg
 

Orb

Active Member
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

Well-Known Member
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.
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Hanging on the wall.
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Leaf temp.
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Hot spot.
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Controller.
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The bottom reading is the canopy temperature.

Sincerest apologies to op
 
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