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Why 5000K only if using 660nm? I get simplifying the design, but I would think you would want a more broad spectrum from white chips (regardless if mixing color temps or not) and supplement 660nm as necessary. Since most common spectrums are driven by 450nm pumps, I believe mixing the Evo...

These plants can definitely take more than 1500ppfd with CO2 supplementation. Most people touting that number have never grown at those light levels, and reference studies that are highly outdated. Fluence did a study showing cannabis yield increases up to 2500ppfd before photoinhibition set in...

I always cover my blue lab guardian screen. Like a flip down cover, something simple.

That is correct. Here is a study that was meant to dispel any ideas that chlorophylls or the epidermis reflect green light. “plant leaves are green because green light is less efficiently absorbed by chlorophylls a and b than red or blue light, and therefore green light has a higher probability...

More modern studies show the impact and importance of green light on photosynthesis, particularly at high light intensities and also in the lower canopy. Green light also penetrates deeper into the leaf tissue. This study talks about comparing red, green, and blue light to background halogen...

Not to be contrarian, but I don’t see any bud bleaching in any of those photos you posted. Some potential light stress, but not bleached buds. I don’t think gauging harvest times was part of the scope of their studies, though harvest times can be manipulated through means other than light...

I run (2) Fluence Spydr 2i fixtures @ about 1340W in 32sq ft. Basically 42W/Sq Ft

Ive grown under quite a few light light sources at different light intensities. I also happen to use Fluence R4 spectrum. To date, the best yields I’ve gotten were under that spectrum at high light intensities. Some tops we’re getting to 1700-1800 PPFD, but most were between 1300-1500 PPFD. I...

There is strong supporting research that total whole plant photosynthesis increases and plants have higher yields when grown under higher Max PPFD, so long as photosynthesis is not inhibited. So more yield out of the same grow space/same life cycle.

I would imagine that light spectrum/intensity would be more of a factor relating to plant morphology, assuming we are taking about a typical 16-18hr daytime period for veg. Longer days will typically need less light intensity, all other factors the same. Edit: this is why I mentioned varying...

The maximum amount of light a plant can use for photosynthesis before photoinhibition sets in, is dependent on many, many variables. This is why you will see different reports from different people. Mostly, folks will talk about light intensity or environmental conditions being the main...

@Rocket Soul THIS study talks primarily about R:FR ratios, which are essentially phytochromes in the active (Pr) or inactive state (Pfr). This article also touches on Crytpochrome blue light response and B:G ratios to determine shade avoidance...

I’ll try to keep this short considering I’ve been writing novels just to try to share my perspective on things. For our discussion purposes, it would have been nice had the study been done using say a 3500k (80CRI) that didn’t have as much red in the spectrum. That said, it’s a very similar...

Here’s the juicy parts from the study for those who don’t want to sort through 60 something pages. Spectrums used A yield reduction would obviously be a negative outcome for any producer especially considering we did not see any significant differences in cannabinoid or terpenoid content...

I’m not sure I’ve put forward any theories other than questioning the total yield/cannabinoid efficacy of supplemental FR light in the presence of a “broader” spectrum of white light. What I should have said, is “I’m fairly familiar with the general concept of the Emerson Enhancement Effect”…...

But Nichia did actually state what diode they were using in those trials you had linked. They put the “conventional LED” 5000k (Ra>80CRI) on the spectral graph next to the Hortisolis chip to so that the reader has a visual understanding of the differences between the spectrum used in their...

This was the study regarding the addition of monochromatic light to white light It looks like they did produce well for you. I’d imagine the results could even be better with some of the other more modern chips mentioned on the “cool end”, and also expanding more into the DR/FR regions. Maybe...

From my many hours of spectrum hunting, reading through data sheets, I have come across a couple of white LED’s that fairly effectively cover the cyan region. Yuji Led APS 3030 5000K Yuji LED APS 5600K Bridgelux Thrive 2835 5700K (Dark Blue Line) Seoul Sun Some of thes options wouldn’t...

I was more or less calling out the study for how it was posited; and therefore any conclusions that could be deduced about how they applied to growing cannabis. Or overall spectrum performance in general relating to high ppfd conditions. I don’t think one can judge how a light will perform...

I did note that you had mentioned it, which was kind of the point I was trying to make. The study cited is fairly disingenuous when comparing those two types of LED chips and expecting to get meaningful interpretations of how spectrum can effect photosynthesis and yield, considering one of the...