Bar Style vs Quantum Board lights

Hey everyone, hope it’s all good for you :muscle::muscle:
I’ve been having arguments about lighting lately and just using my own logic, i keep saying to people that Bar Style leds are great for a flat, even and not very deep canopy, and that a Quantum Board style light usually performs better at more distance from canopy but will penetrate deeper, because more watts concentrated on a smaller area…
That’s my logic…
What do you guys think?

I believe Bar Style were developed for microgreens and smaller plants in vertical farming, not exactly ideal for dense cannabis plants…

I would love to hear from anyone that can elaborate on this subject

I haven’t been around here too much lately, so i can only remember about @dbrn32 and @Hellraiser

Any input will be much appreciated :muscle::muscle::muscle::muscle:

Happy growing everyone!


I feel the same. Bar style - a bit better even coverage because of the spread out LEDs, QBs - more light intensity, better penetration.


There should be more available info about how deep a canopy should be to match a specific light source…
Not all of us are SCROGing the perfect flat and thin canopy at flowering…
I feel like a longer reach light would work best for me and many people…
All of those Bar Style leds have to be like at 12 or 10 inches at flowering, but how deep will they go after that with useful light?

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There is more to do with light penetration than sheer intensity. In a lot of instances a more diffuse light will reach deeper into canopy than a more intense light from smaller light emitting surface. I think there are a lot of variables that could make either seem better in different situations. I would typically recommend a bar styled light more if everything else in comparison is equal.


Ok, that makes sense…

More light sources sending light in more directions…

But the thing is that a QB still provides more power on a smaller area…

I guess the actual shape of the canopy would have a big impact too, like the arrangement of the leaves and branches…

I see that the QB style fixtures for a determined area use more watts for the same area than Bar Style, but the recommended distances to canopy are around double the distance…

So, if the canopy is perfect, i would guess that the more efficient way to do it is Bar Style, but otherwise, with most people having irregular canopies, like top buds 10" from the lower buds through a canopy, wouldn’t people benefit more from a light that holds intensity into longer distances?

Thanks for the replies gentlemen, i usually don’t have anyone to talk about these details :pray::muscle::muscle::muscle:

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Like you said, there a lot of variables. That’s why I like to measure. How much better is the penetration? We could speculate, but the only way to know for sure is to take a measurement.

For a larger tent like a 5x5, I think you’ll be pretty disappointed with the numbers you’re getting in the corners with a QB.


Light doesn’t actually go through leaves very well. So just because intensity is higher doesn’t automatically mean penetration is greater.


I’m not going to concern myself with trying to penetrate through the canopy. I’m just going to keep adequate spacing such that some side lights will be plenty to properly illuminate the entire plants. All growth below the canopy will be trimmed enough to avoid major light blockage among the plants.

It seems to me a bit futile to fight how plants are lit in natural environments. In my experience, having enough light above the canopy to be sufficient enough to benefit lower growth is far too much for the canopy. I try to do things the easy way and dislike unnecessary steep uphill battles.


This^^^ plus the light ‘penetrating’ upper leaves is :green_square:green:green_square:, therefore mostly useless regarding PAR.

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