Yields at differant PPFD?

BuddyColas said:
These guys are a big warehouse type of commercial grow using HPS DE and LED. It could be argued that the DEs heat the place up to a temp that the LEDs can perform well...but worth watching if you have not seen it.
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Problem with this is we are talking very specific ppfd. His DE are way too high.
Would love to see a watt for watt Cob vs de grow,
 
Stephenj37826 said:
No doubt lol. Most don't grasp that there is in fact a big difference between IR radiant heat and cascading conductive heat.
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Well aware. Id say both a used in different operations.
Anyways, we are all getting way off topic. Ill make a thread and we cann go there.
Just so we all know 600 - 800ppfd is 25% increase.
As for Gavita, sure they are a bit biased for sure and always take what they say with a grain of salt.
Main thing is ROI.
Would love to see a watt for watt comparison of COB vs DE.
I appreciate both for different applications. I also am yet to see a warehouse use COB due to long ROI and investors dont like that.
 
LED vs HPS...LED vs LED...HPS vs HPS...

None of it matters. And gavita can say whatever about the leds they tried...they clearly, and conveniently, leave out the details of the tes(PPF/area/wattage/everything)that would show what they saw what they saw.

But if you want to see a real test is...
PPF vs PPF...that is it. Nothing more, nothing less.

Doesn't matter where the hell the photons come from. Match the photons...and you have yourself a test.
After that you can account for whatever it took to achieve the PPF, and compare(cost, energy, time, whatever).

But if you want results...then use the amount of light that correlates to the growth needed. LED's are not a magical photons or light...photons are photons.
And with that said...a watt is a watt and produces the same amount of heat regardless of efficiency. Even counting the photosynthesis process...that energy will be released as heat.
And though holland greenhouses can get cold...most denver, CA, and Wa and others indoor facilities are not supplementing heat, and is one of the major reasons for adoption.
If I want head...I will use a very efficient source of heat...not a somewhat efficient light to comprose. Use efficient lighting and heating...efficiency of your grow/facility counts on everything.

I, gavita, and tags have all said near linear to 1000µmols many times. As well as given our findings on saturation levels. All coinciding with the majority of published data.
 
Pictures worth a thousand words, right? X10 lux meter reads just above 1500.. So 1,500 foot candles and over 15,000 lumens. I'm in 3x2' ft. Is this good, bad, could be better? What u guys think? What does this mean for my PPFD? Thanks.. This is under 4 cxb359020160429_114306.jpg
 
Greengenes707 said:
And with that said...a watt is a watt and produces the same amount of heat regardless of efficiency. Even counting the photosynthesis process...that energy will be released as heat.
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Come again? That energy will be trapped in chemical energy and biomass aka glucose, oxygen and frosty nugs.

You were good up until you broke the first law of thermodynamics.
 
JorgeGonzales said:
Come again? That energy will be trapped in chemical energy and biomass aka glucose, oxygen and frosty nugs.

You were good up until you broke the first law of thermodynamics.
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No. It gets stored...then release at a point...which still has to be dealt with. Even the photons used to fix carbon, not all the energy is used and the rest is released. Thermodynamics was not ignored.
 
Greengenes707 said:
No. It gets stored...then release at a point...which still has to be dealt with. Even the photons used to fix carbon, not all the energy is used and the rest is released. Thermodynamics was not ignored.
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The point it's released is when you smoke thosy frosty nugs. You can't convert light into plants and get the same amount of energy back out. That is the literal definition of a perpetual motion machine.

A more efficient light source -over plants- will generate less heat, period. Without plants, watts is watts, but let's not get carried away here.
 
GroDank101 said:
Pictures worth a thousand words, right? X10 lux meter reads just above 1500.. So 1,500 foot candles and over 15,000 lumens. I'm in 3x2' ft. Is this good, bad, could be better? What u guys think? What does this mean for my PPFD? Thanks.. This is under 4 cxb3590View attachment 3668965
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How hard are you running your cobs, and how high are your lights above your canopy now?
 
GroDank101 said:
Pictures worth a thousand words, right? X10 lux meter reads just above 1500.. So 1,500 foot candles and over 15,000 lumens. I'm in 3x2' ft. Is this good, bad, could be better? What u guys think? What does this mean for my PPFD? Thanks.. This is under 4 cxb3590View attachment 3668965
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Conversion of about .014 for Cree 3500k. So that point roughly has a ppfd of 210.

If you've got 4x 3590s @ 50w each in a 3x2, you should have an average ppfd of 800+.

Edit bad msth
 
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I used to run 2x 1000w hps air cooled and am now transitioning to LED. Now I have a 680watt LED fixture, 480 watt LED fixture and a 1000 watt air cooled hps and my room is definitely cooler than before. I've read about how a watt is a watt when talking heat, but the way these put out heat doesn't translate the same in the room. I don't know where the heat is going, but I'm cool with it.
 
@BuddyColas yes that's right, 4 cobs at 1.4 amps. 255 ppfd sounds low to me, but you might be right. But The plants seem happy but I'm no expert, yet. They are at 50w each I believe.
According to info posted above, I'm assuming there's a difference between ppfd at a specific point and the total average ppfd. Is that right? I never knew about the Cree conversion factor or .014 before now.
 
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GroDank101 said:
@BuddyColas yes that's right, 4 cobs at 1.4 amps. 255 ppfd sounds low to me, but you might be right. But The plants seem happy but I'm no expert, yet. They are at 50w each I believe.
According to info posted above, I'm assuming there's a difference between ppfd at a specific point and the total average ppfd. Is that right? I never knew about the Cree conversion factor or .014 before now.
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So if you go to apogee.com they have some conversion factors for lux to ppf. CMH factor is 15.4 x lux in thousands and is very close to white cob. If you want a closer ppfd reading you could take sample readings around your canopy, which is all you care about, and average them. In short...you need more photons to your canopy.
 
If you're measuring a single point, converting to ppfd just tells you the same point. To calculate average ppfd, take total lumen output(4x 8,900), divide by square meters of your space (6 sq ft / 10.7), and multiply by conversion. (.0145)

If using kilolumens just multiply by 14.5


There's another way with par watts and something, lumen output is usually just easier to find.
 
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