Can a light get too efficient
- Thread starter Uncle Reefer
- Start date
coreywebster
Well-Known Member
Only half a dozen. You should log on more
mahiluana
Well-Known Member
this is already answered above // peak of carotenoids + high ratio of cyan in natural daylight
when i eat carotenoids (vitamine A, beta carotine....they help me to drive my eye function / my photosensitive antenas. They also cause a visible yellow/orange pigment in my skin, that helps to manage the skin protection against sun radiation.
As far as I know - carotenoids inside a plant help to protect the plant (specially in midday summer sun) against too high intensities of light, that otherwise would stop photosynthesis completely. So even the function of carotenoids inside plants and humans are very similiar.
The first plant that i cut in my life, was 40 years ago - the first plant of my life, that unfortunately was standing in the middle of a sunny place in my parents house. OK. --- a bit stupid.
When i had to cut her it in plain vegging - the plant squized a red/orange liquid out of the stem.
Apparently very close to my blood color. --- That were carotenoids - i`m shure
how do you explain the presence of carotenoids - and why should a phototropical plant that need a DLI
specially renounce or ignore this most present wavelenght during evolution (2000million years)
you see the peaks of such a spec in my photo above - its clearly 490/600amber
to fill a gap in a 450/630nm just perfect. And if you look to the lumens for humans and CRI
These epistar 3w cyan are rated 90lm/w the royalblue only 60lm/w acording to what we know
about luminous efficiency of our eyes.
We find ~ the same comparing lumens of orange and > yellow. ---> the closer we peak @ 555nm green - the more lumens we can expect.
So far - next christmes i write it down for Sta. Claus
I like a chip with a mixture of 400,450,490nm die + covered all with the same red/yellow phosphor630nm /// 3 band but only one Vf- channel.
i found a patent but no product --- you and your spectralmeter are invited for some growlightresearch
Last edited:
Rahz
Well-Known Member
Agreed, but it's difficult to quantify without a perfect sun spectrum that can be used in an indoor environment. Perhaps a greenhouse could be used to equalize all parameters except light.
Anyway, the basic theory is that by targeting the most efficient wavelengths you get more photosynthesis.
Lamp 1: Sunlight
Lamp 2: 20% blue, 50% orange (610) 30% deep red (660)
Lamp 3: White cob
I think comparing yield from lamp 2 and 3 would provide useful data.
Uncle Reefer
Well-Known Member
Keep it civil kids, lots of great opinions and facts here, I never thought my thread would grow its own life like this. That is all carry on
wietefras
Well-Known Member
Bugbee did a test with several spectra like R+B and several white CCT's between 2700K and 5000K. The R+B and the whites till 4000K were within 5% of each other. With the R+B scoring highest and 4000K lowest of those within 5% (5000K still lower). Showing spectrum isn't really that important for yield. Within reason.
His results pretty much exactly followed what you would expect if you rank the lights according to McCree's RQE chart.
wietefras
Well-Known Member
We know you are man, but the shit you post is so wrong that it's hilarious anyway.
See? Hilarious.
because ... wait for it ...
There is no Olson series ... it's called Oslon or OSLON.
OneHitDone
Well-Known Member
Since this is a spectral free for all.... What are some thoughts on this vid?
Are many of this led's squishing plants into bonsai's due to the lack of far red?
Are many of this led's squishing plants into bonsai's due to the lack of far red?
wietefras
Well-Known Member
Leaves pretty much only let far red light pass through them. Plus you'll get perhaps a tiny bit of extra green since that reflects a bit more off the leaves and can "bounce through".
So yeah, "canopy shade" is very heavy on the far red side and a "man made" shade, which simply limits the amount of sunlight passing through, looks just like sunlight (but dimmed).
Malocan did some tests on sort of the same subject with his spectrometer a while ago. I added the results he showed. The first is without the leaf (ie the SPD of the COB itself) and the second is the SPD of the light that went through the leaf (IIRC it was a few leaves stacked on top of each other).
Around 760nm you see about 35% of the light making it through the leaves while for the rest it's around 1% (ie pretty much nothing)
Attachments
Last edited:
Rahz
Well-Known Member
Interesting. My tests so far haven't followed a Mcree prediction. It's always been the high CRI sample that wins out or breaks even, even when output from the low CRI is high enough to more than offset a Mcree bonus to the higher CRI. Were they ranking by plant mass or flower yield?
Visually from viewing various spds in mfg datasheets the high CRI (Ra 90, Ra 95) seem to rank higher based on a McCree RQE than a low CRI.
Rahz
Well-Known Member
Yes but not high enough to make up for the loss of energy used to achieve the high CRI.
I'm confused ... didn't you just say that "the high CRI sample that wins out" ?
Rahz
Well-Known Member
The high CRI benefits more from a Mcree adjustment but the low CRI puts out more energy, enough that on paper it's still going to yield more even when adjusted for photosynthetic efficiency.
So on paper the better spectrum doesn't make up for the energy loss, yet the high CRI samples produce more yield nonetheless.
This leaves me considering the possibility that vegetative predictions/photosynthetic efficiency of leaf matter isn't making an accurate flower prediction. It's possible that red/deep red should be weighted more than it currently is for the purpose of estimating flower yield.
Mcree is predicting the low CRI will yield more, which I think it might during the vegetative period. The 3000K 70CRI lamp I have has been producing the fullest bushes, but that extra power isn't translating into more yield. The high CRI wins even though it's still getting a lower mark after being adjusted for the Mcree data.
So on paper the better spectrum doesn't make up for the energy loss, yet the high CRI samples produce more yield nonetheless.
This leaves me considering the possibility that vegetative predictions/photosynthetic efficiency of leaf matter isn't making an accurate flower prediction. It's possible that red/deep red should be weighted more than it currently is for the purpose of estimating flower yield.
Mcree is predicting the low CRI will yield more, which I think it might during the vegetative period. The 3000K 70CRI lamp I have has been producing the fullest bushes, but that extra power isn't translating into more yield. The high CRI wins even though it's still getting a lower mark after being adjusted for the Mcree data.
Last edited:
I agree for flowering cycle the yellow/red/deep red may need more weighting. Beyond Cannabis, farmers have known for at least a century that yellow to red heavy lighting is best for flowering fruiting plants.
nfhiggs
Well-Known Member
Light is just the absence of dark. Lights don't really put out light, they just suck up dark - that's why electronic schematics always label lights as "DS1, DS2, etc". DS stands for "Dark Sucker". Dark has weight too - it sinks to the bottom of lakes and oceans and makes it all dark down there.
Its TRUE, I read it on the internet.
wietefras
Well-Known Member
This was about leaf growth (dry mass) of tomato, radish, cucumber plants and such.
Although I have seen other tests where they grew tomatoes and spectrum didn't make much of a difference on fruit yield either. Ultimately fruit growth is also driven by photosynthesis.
The reason we choose more blue for vegetative phase is for photomorphogenesis reasons. To grow the plants more bushy and have less stretch. On the other hand we use less blue during flowering to get less leaf growth in the cola's, but mostly because HPS lights were simply more efficient. We also don't care about stretch during flowering since the plants stopped growing.
We moved from the 1800K of HPS to 3000K-3500K with COBs, simply because the COBs are more efficient in producing photons than HPS. In the end we all follow where the photons are produced.
Anyway, in this Bugbee test, the difference will be that they were working with fixed intensities for all SPDs. So it shows that "better" spectrum doesn't do much for yield. Comparable to what McCree's RQE chart would predict.
The benefit of 70 CRI is that you get more photons for your watts. So when you keep the power input the same then it would beat the others on higher light intensity, but when you grow plants under the same intensity 70 CRI light vs 80 CRI light, I assume the 80 CRI would "win".
Agree though, for us g/W is more important than g/PPFD
Last edited: