Optimized LEDs Produce More at Higher Temperatures Than HID or COBs?

[wirat]

I was deciding whether to build a DIY COB LED or go with a commercial multi-band one like you find at Kind LED or BlackDog. I have read where people say that LED grown bud is airy and not as dense as HPS.

So to my surprise I found information that states in part: "LED lighting optimized for plant growth does not produce an excess of infrared, yellow or green light like other artificial grow light technologies, including "white" LEDs. Because leaves aren't being directly warmed by these spectra that plants cannot use, plants grown under LED grow lights require warmer ambient air temperatures to achieve optimal metabolic rates." The ideal LED air temperature is claimed to be 84-86 degrees F.

I found this from more than one source. According to this information, only the multi-band LEDs would benefit from (reach optimal metabolism) higher temperatures for the reason stated above and "white light" would not, so this doesn't apply to COB LEDs since they are all white.

Here are two sites that discuss it:
https://www.blackdogled.com/lst#What_is_ideal_LST
http://silassativarius.org/2015/02/03/3-keys-to-maximizing-plant-growth-temperature-co2-and-plant-metabolism/

Has anyone here using optimized LEDs tried warmer temperatures and discovered it to produce better? Sure would be nice for higher temperatures to be an advantage rather than something to mitigate.

 

[GreenSanta]

Been growing with LEDs for about 4/years with warmer temps on and off and I have always got great results from 75-85 ... 85-90 can give great results strain dependant, but also hairy sometimes from high temps, not airy though .i just ran my first round with cobs I would say I was around 80 and everything came out fire

 

[GreenSanta]

Also generally as dense as it gets, again, strain dependant. I should add I have always used over 40watts a sq.ft so I have never cheaped out on power... I think low wattage per sq ft might be where the airy weed comes from

 

[grouch]

How do they know that plants can't use the other spectrums found in white light?

 

[Rahz]

There's plenty of evidence plants use the entire visible spectrum and benefit from small amounts of infra-red radiation as well as UV.

 

[wirat]

How do they know that plants can't use the other spectrums found in white light?

The one link to BlackDog above explains their research and here is another reference:
http://www.illumitex.com/full-spectrum-light-plant-growth/
I don't think it means white light is not good, just that it contains more than what plants need to thrive and that if you design a light tailored to just the optimum spectrums then you can create a more efficient light that uses less wattage to only produce light the plants will use. That's the standard argument as to why optimized LEDs produce less heat and use less power (more efficient) than HID. I'm still on the fence about it.

 

[Stephenj37826]

The one link to BlackDog above explains their research and here is another reference:
http://www.illumitex.com/full-spectrum-light-plant-growth/
I don't think it means white light is not good, just that it contains more than what plants need to thrive and that if you design a light tailored to just the optimum spectrums then you can create a more efficient light that uses less wattage to only produce light the plants will use. That's the standard argument as to why optimized LEDs produce less heat and use less power (more efficient) than HID. I'm still on the fence about it.

Its simply not true. Spectrum takes a back seat to total photon count in the 400-700 nm range. If that was the case why would a successful and much more reputable BML stop producing there mono based spyder series and go with warm white deep red combo? Do some searhing even NASA has come out and said that monos aren't as good as high CRI white light. Also look up the macree curve. If plants could only use what black dog states hps wouldn't grow anything but we all know that's not the case. Also notice how they don't even disclose what brand diodes they run. Also do some research on overall plant health under monos vs full spectrum. Also from what we are seeing optimum temps for growing under cob lights is around 82 F. I would still depend on how much light they are getting. A $35 dollar laser thermometer is the best way to check leaf surface temps.

 

[churchhaze]

Yellow and green are some of the most important wavelengths. Without a full spectrum, the top canopy would be saturated with red and blue even at low light levels and nothing would get to the bottom of the plant. Yellow and green feed the under-canopy while causing a slight %Pfr gradient between the top and bottom of the plant. The slight %Pfr gradiant causes the lower branches to stretch until they reach light that still has red in it. This helps shape the plant in a positive way.

 

[frica]

@wirat
I suggest you read http://rollitup.org/t/old-news-for-potheads.895710/

Green light is beneficial.
White light > blurple.

Blackdogled has posted bullshit on their site before, see their "efficiency myth" article.
I can't trust them, they're just trying to sell their "5 watt" led lights for as long as they can before they step over to something new.

And between blue and green, for some plants green trumps blue. Even though 100% red did the best for Salvia, Green+red did much better than Blue+Red (blurple)

 

[wirat]

I hear you guys and I'm not discounting that white light isnt beneficial, or better, and I realize that it is primarily the LED indstry who are making these claims. Just wanted to make sense of the claims and see if there was any validity to this higher temperature thing. I see the majority of replies here thinks not. I will check out the references you all provided. Thanks!

 

[Greengenes707]

Ask each of these companies that claim to hit the chlorophyll peaks, and that thats the important thing to do...what is the response to light when not extracted with a needle, mixed with alcohol, and excited in a test tube?
Whole intact leaf response is what matters. Where all pigments, accessory or major, interact and drive photosynthesis.