The Ideal spectrum.

jjng5

jjng5

Well-Known Member
TEKNIK said:
I honestly do not believe in an ideal spectrum, I think it needs to change to mimic nature. It probably doesn't need to exactly mimic nature but I think it needs to have high amounts of blue and green light mid way through the day with heavier reds when first turned on and when it is finishing for the day.
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Again, I get the basic theory. I think we all do. Plants like light. No doubt. But when I paint a wall do I want to use a paint brush to apply it with precision or do I just throw the whole bucket of paint at the wall until some lands on the dry wall with the other half landing on the floor? Do you get what I'm going for here? This is more theoretical for light planning based upon the research and the data than understanding light basics the way I see it. And these are the answers I'm trying to figure out.
 
TEKNIK

TEKNIK

Well-Known Member
jjng5 said:
Again, I get the basic theory. I think we all do. Plants like light. No doubt. But when I paint a wall do I want to use a paint brush to apply it with precision or do I just throw the bucket of paint at the wall until some lands on the dry wall with the other half landing on the floor? Do you get what I'm going for here? This is more theoretical for light planning based upon the research and the data than understanding light basics the way I see it.
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If I woke you up in the morning blasting 100,000 lumens in your face what would you do?
 
ChiefRunningPhist

ChiefRunningPhist

Well-Known Member
jjng5 said:
I understand that part, but then the question becomes "how much?". Am I right? It's all about dosing in quantities that matter. Not even quantities so much as ratios once we assume enough quantity. That's what I'm trying to understand. I get that red light is prioritized, then blues/white light, with green light being last once the first two are satisfied first.

For example, I look at what I have, per flower tent = (2) HLG324's @ 3500k - ~330watt total, (4) QB144's @ 3000k ~ 250watt total, and (2) QB96's customized [64 High power White, 16 Red (660nm) and 16 Deep Red (660nm)] ~390watt total. That breaks down like this:

330w - 3500k
250w - 3000k
390w - 67% whites/blue 33% reds/far-reds
= 970 watt total

= 60% mid-spectrum white/greens, 40% red/far red

What I'm trying to decide is if that's spot on or imbalanced based upon the data? Obviously quantity is there at ~39 watt/sq foot of LED QB's. What I'm wondering is if I've properly balanced the ratios in the most efficient way.
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Seems red & blue are optimized to about 1050-1100ppfd and that after that, the only beneficial WV is green. That's what I understood it as at least.
 
TEKNIK

TEKNIK

Well-Known Member
jjng5 said:
If it's 100k of UV or Ultrasonic light I'd probably roll over... that's my point. I don't think you're understanding me. It's cool though
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I would try and hide being woken up light that, I would be pissed off as fuck, I personally like to wake up in the dark, I like very soft light without any blue and after the sun rises then I get moving for the day under bright light. I don't think a plant is much different to me
 
TEKNIK

TEKNIK

Well-Known Member
We do not know the correct ratios for a good reason, I don't believe that there is one or it would have been figured out by now. We do have indications of what does work better than others. A HPS is 2000-2200k. Leds most of the time people are using 3000-3500k, beyond that too much blue seems to have a negative impact. Plants seem to enjoy less blue during flowering but is this because the focus of blue light under leds is at 450nm or is it possible that they do still want blue light but not all the time.
 
ChiefRunningPhist

ChiefRunningPhist

Well-Known Member
jjng5 said:
That's what I'm trying to explore. I'm just wondering at what point, maybe we don't even know yet.
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You know I went and searched all over my data files for where I got that PPFD number from, and I can't find it anywhere! Im sorry man I think I may have mispoke.

Here's a chart and it looks like honestly the threshold is closer to 225ppfd than 1100...

Averaged integration of the other 2 graphs...
Screenshot_2019-04-11-13-41-10~2.png
smLeafOrientation.jpg
Not sure what area under the curve is defined as with these graphs, but it seems top of leaf side has a threshold of around 225ppfd...
Screenshot_2019-04-11-13-40-48~2.png

EDIT:
The threshold for the leaf underside seems even lower, and possibly why green light in HPS is seen as beneficial or has a greater "penetration" effect because of how much is reflected down the plant. The top can't utilize it and so its reflected instead of absorbed and the underside is able to utilize it more effectively. ???? I'm adding green lights to my build for this reason..
 

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TEKNIK

TEKNIK

Well-Known Member
ChiefRunningPhist said:
Look at the difference in dry weight vs leaf area and number of flower sites. Kind of interesting. I know it's only tomatoes but still interesting..
View attachment 4315808

This is just a blurry graph of various lighting technoligies...
View attachment 4315809
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Any studies on how a tomato plant yields should be taken into consideration as it's one of the closest things in terms of energy needs to canabis
 
nachooo

nachooo

Well-Known Member
TEKNIK said:
A hps is low in red and blue light, can't deny that they work great though. My belief is that because they are high in green light this opens up stomatal to absorb any photons they can get. Red and blue light is useless unless the plant can accept the photons produced. I worked this out a long time ago long before people started to use COBs to grow with.
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Sorry I dont know if I am wrong..but you are saying: "My belief is that because they are high in green light this opens up stomatal to absorb any photons they can get"
Stomata does not absorb photons….stomata relates to gas exchange..CO2 absortion.. Photons are absorbed by pigments..like chlorophyll and are located in the chloroplast….
Big confusión here
 
TEKNIK

TEKNIK

Well-Known Member
Everyone is trying to get the best PAR efficiency, but the evidence shows that PAR efficiency doesn't mean anything without having a broad spectrum. If PAR was so important than everyone would just be growing under 660nm and nothing else. I have stopped worrying about PAR efficiency and I have started focusing on light quality for this reason. It may take some time for a new breakthrough to happen but I think it will happen soon.
 
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