Is this light burn?

[Delps8]

Yup, was in denial myself last two weeks, but after measuring and a lot of calculating, and a lot of reading here through these threads, turned the knob back. Seems like heat and light stress are two different things, and one in the same.

Denial ain't just a river in Egypt. One of my little theories about human nature is that we tend to stick with things because that's how we got to where we are today and, hopefully, we're thinking a pretty decent person. So, yeh, we hang on to things a little longer than we should sometimes. The good thing is that we have places like AFN where we can get solutions. Sometimes it just takes a nudge (and, sure, sometimes we need our ass handed to us but that's another story!)

"Seems like heat and light stress are two different things, and one in the same
Now you're going all Zen on us!
That is a good way to put it and that will help everyone who reads the thread deal with this issue a little better.

 

[GreenhouseGreen]

Ya, I have a link too though that they gave me. I had one for Timber too, but I need to ask them for an updated one. I like to save people money if I can. Most that have been here awhile know about the HLG code, but newer people don't so I'm posting that code a lot. Just saved @CaseyQuinn a few bucks. I thought he knew the code, but I said WTH, I'll mention it just in case. Good thing I did.

I just used the HLG code a few days ago and saved $62. Always nice.

 

[CheGueVapo]

inaccurate at guarding temperature

You dont guard the temperature, but the radiation... that we can greatly measure. We cant determine the temperature precisely... but we can FEEL the heat radiation that WE CANNOT SEE, heating us up higher, than without. You are wrong... you think about heat as if it just were temperatures of a surface..... most people think heat is just temperature and it can just transfer with air via convection or conduction from one surface to another... thats WRONG! Everything radiates HEAT (except the vacuum)! Radiating Infrared is primary the way of heat moving! Even at equilibrium, when emission and absorbtion is the same and the ambient and surface temperature ARE the same.... still they are emitting and absorbing THEIR LEVEL of radiatio ALL THE TIME same high! Doubling the temperature of a surface to its ambient makes the radiation go 16x! Thats the law of Stefan Boltzman!

That was only the heat-radiation.

But you feel the light-radiation absorbing and heating your hand too! SO it works... with your hand you can determine if the light is too close and too hot! LEGIT... you dont need the "temperature feeling" of it! If it heats your hand, than it heats your plants! Increasing the distance heats your hand and the plants less! But SAME does reducing the light intensity at closer distance... if you can afford the homogenity and spread of the light through the square at the close distance.... the closer the more efficient! Same effect with less power!

So instead of 10feet high 2000W... theres quite better ways off efficiently lighting the plants Honestly its just a waste this way.. and still burned, because everything is reflective... than distance doesnt make it better! Wasnt quite clever. Was simply tooooo much andmaybe run out of water on that intensity.... thats a killer-combination.

 

[CheGueVapo]

Get your head around this:

SAME temperature all sides, but completly DIFFERENT radiation... depending on the surface!

You can feel that if you hold your hands and wait... you feel it warming you!
Thats what you feel infront of a fire or an oven.... not the "air". But the radiation of the heat!
When stand infromt of a cold big plate that absorbs good and does not reflect your emission.... then you feel it sucking out your radiation... there is nothing coming back, and so you cool out fastly. Like if you are naked in space! You radiate out within short time and nothing comes back at you! You freeze!

You can measure that feeling perfectly! The temperature doesnt matter... you feel heating up and you feel freezing out! Dont you KNOW that feeling? It is so important for your survival, that when you feel that, it tells you CHANGE IT! Or you die baked or frosted!

 

[Week4@inCharge]

Someone here mentioned IR lighting and I got it confused with UV lighting...my bad, as you were .. (my fixtures,led lighting, has a few "IR" diodes, so not sure what that's about)

 

[rmax]

turning down the dimmer knob

I agree turning down the dimmer knob makes human senses perceive a decrease in heat and light. Does turning down the dimmer knob change the wave length of the output light and what impact does the changed wavelength have on the plants, if any?

Like you pointed out we can't use human senses. Using HPS as example, when a 1000w is dimmed to 400w the color of the light changes. I don't know how to measure the light frequency change impact to the plants. That's why I mentioned I'd have to buy new ballasts to switch from 1000w to 400w.

Note: I have dimmable Vs switchable ballasts.

Does the LED driver automatically compensate for the light wavelength changes do to being dimmed?

 

[Week4@inCharge]

I agree turning down the dimmer knob makes human senses perceive a decrease in heat and light. Does turning down the dimmer knob change the wave length of the output light and what impact does the changed wavelength have on the plants, if any?

Like you pointed out we can't use human senses. Using HPS as example, when a 1000w is dimmed to 400w the color of the light changes. I don't know how to measure the light frequency change impact to the plants. That's why I mentioned I'd have to buy new ballasts to switch from 1000w to 400w.

Note: I have dimmable Vs switchable ballasts.

Does the LED driver automatically compensate for the light wavelength changes do to being dimmed?

No way to really know unless tested, and the public perception is that yes the wavelength is the same just the output limited. So the dim doesn't work? if you dim it down your visual and sensual perception is incorrect? And the meter readings are wrong too I suppose. Sounds like a Jedi mind sentence there to say turning down the knob makes the human senses "perceive" a decrease when instruments say, yes, there was a decrease, oh and you didn't read this here.

 

[Three Berries]

What about some sort of screening to filter the too much LED?

 

[Week4@inCharge]

Punk the new guy day ..lol, I get it now.. ok, ha ha clever guys very clever. jokes on me today.

 

[rmax]

No way to really know unless tested, and the public perception is that yes the wavelength is the same just the output limited. So the dim doesn't work? if you dim it down your visual and sensual perception is incorrect? And the meter readings are wrong too I suppose. Sounds like a Jedi mind sentence there to say turning down the knob makes the human senses "perceive" a decrease when instruments say, yes, there was a decrease, oh and you didn't read this here.

Sorry about the Jedi. Dimmed power, less lumens, bulb looks dimmer. But did the waveform for plant photosynthesis change?

Put another way, does a 1000W HPS bulb in a 1000W HPS ballast dimmed to 400W output the same waveform as a 400W HPS bulb in a 400W HPS ballast. The graph you posted is usable.

Thinking about LEDs are they designed to always output the same wavelengths no matter the input wattage?

I want good plants like you posters and am trying to understand the lights. I have to change my lights. It's gotta be the lights. How can I make waveform graphs like you showed us?

 

[CARmick93]

Does anyone on here use silicon when growing? I’ve been reading up on it and apparently it can make your plants more resilient to heat and light stress? It’s Also meant have a lot more benefits and give increased resistance to pests and disease.

Think I’m going to give it a go on my next grow, the ones I’ve looked at, growth technology liquid silicon and plant magic bio silicon seem like they will help. Anyone know which is the better between the two or any other advice on using them?

 

[CheGueVapo]

Does turning down the dimmer knob change the wave length of the output light

Some LED chips are sensitive in wavelength to the currents driven.
The luminus 405nm is a good example. When you drive it very low currents its gets some +1-3nm.
Check the datasheets of the chips for details.
The wavelength of the most LED-chip are more sensitive to temperature, the higher the temperature the more the wavelength peak of a chip moves up. But you need very high "damaging" (on the long term) temperatures to achieve only some nanometers shift. It's neglible.

Ultra low currents change the color point of amodern white LED like the LM301H only neglible, but the efficiency improves further... it's worth investing lots of those highly parallelised in high SL-bins.

Check these masterpieces of modules:

FLUXengine LED module with Samsung LM301H - DIY Grow lamp

The FLUXengine LED module with Samsung LM301H is the best choice for DIY LED plant lamps. Just build a frame, wire the modules and let's grow!

cre.science

 

[myke]

Does anyone on here use silicon when growing? I’ve been reading up on it and apparently it can make your plants more resilient to heat and light stress? It’s Also meant have a lot more benefits and give increased resistance to pests and disease.

Think I’m going to give it a go on my next grow, the ones I’ve looked at, growth technology liquid silicon and plant magic bio silicon seem like they will help. Anyone know which is the better between the two or any other advice on using them?

A proper balance of NPK and good watering habits do the same thing. Allowing potassium to do its thing is all you need.

 

[ComfortCreator]

I do no think this is just light burn. Usually we have our lights on strong enough that they are set for a plant growing really well.

Any problems will get worse under strong lighting. I believe there is/was an imbalance in either nutrient concentration and/or ph. With either of those issues, and potentially both, the lighting will magnify that problem.

For example, look at the leaves not as badly burned. They are heavily spotted, not from lighting, but from a nute/ph issue. It may have a cal deficiency showing as one possibility. And whatever issues there were, the lighting, set to high will make it a lot worse.

I only say all this to call attention away from the thinking that this is a simple lighting issue. If the other issues were fixed, I think this would have not been an issue, or at least would have been less of one. Just another 2c added...

 

[Delps8]

You dont guard the temperature, but the radiation... that we can greatly measure. We cant determine the temperature precisely... but we can FEEL the heat radiation that WE CANNOT SEE, heating us up higher, than without. You are wrong... you think about heat as if it just were temperatures of a surface..... most people think heat is just temperature and it can just transfer with air via convection or conduction from one surface to another... thats WRONG! Everything radiates HEAT (except the vacuum)! Radiating Infrared is primary the way of heat moving! Even at equilibrium, when emission and absorbtion is the same and the ambient and surface temperature ARE the same.... still they are emitting and absorbing THEIR LEVEL of radiatio ALL THE TIME same high! Doubling the temperature of a surface to its ambient makes the radiation go 16x! Thats the law of Stefan Boltzman!

That was only the heat-radiation.

But you feel the light-radiation absorbing and heating your hand too! SO it works... with your hand you can determine if the light is too close and too hot! LEGIT... you dont need the "temperature feeling" of it! If it heats your hand, than it heats your plants! Increasing the distance heats your hand and the plants less! But SAME does reducing the light intensity at closer distance... if you can afford the homogenity and spread of the light through the square at the close distance.... the closer the more efficient! Same effect with less power!

So instead of 10feet high 2000W... theres quite better ways off efficiently lighting the plants Honestly its just a waste this way.. and still burned, because everything is reflective... than distance doesnt make it better! Wasnt quite clever. Was simply tooooo much andmaybe run out of water on that intensity.... thats a killer-combination.

I typed “guarding” - the word I wanted was “gauging”.

“you think about heat as if it just were temperatures of a surface” - Perhaps the guarding vs gauging typo lead you to that conclusion but I am under no such misconception. Even my O level knowledge of physics taught me that.

My point is that humans suck in being accurate in determining things such as temperature, weight, etc. We’re just lousy at it. One can quibble over the meaning of the term “lousy” but that’s not something that I’m interested in.