Rasser
Active Member
Looking at the Illumitex LED them self doesn't revile any specs, regarding the specific spectrum's used.
http://www.mouser.com/illumitexhorticulture/
http://www.mouser.com/illumitexhorticulture/
Self-made LED panel general discussion
- Thread starter patrikantonius
- Start date
PetFlora
Well-Known Member
Let me use this analogy:
If you've only ever eaten average steak, you would not know how wonderful an organically grown grass fed steak tastes. Hell you might not even appreciate it.
It seems you are content with where you are on the importance of 500-600. So be it.
As they say in Texas, you can lead a horse to water but you can't make it drink.
If you've only ever eaten average steak, you would not know how wonderful an organically grown grass fed steak tastes. Hell you might not even appreciate it.
It seems you are content with where you are on the importance of 500-600. So be it.
As they say in Texas, you can lead a horse to water but you can't make it drink.
Gastanker
Well-Known Member
If we are throwing out spectral absorption patterns because they are based on spinach, tomato, and lettuce, than can we really say that LEDs manufactured to grow lettuce are any good for bud? Not at all trying to bash illumatex but to assume that they are great because they grow lettuce large scale seems a bit off.
Rasser
Active Member
Please we are talking about a spectrum of light, not taste or eating with good conscience.
No I'm not content, I've just not see any evidence that green light should have any special purpose.
Rasser
Active Member
I'm not following your ways of dividing the wavelength to get results.
Could you please look at this page, where there is a WL vs. Ev calculator.
http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon
When using that, there is this difference in energy between the to states of vibration.
A red photon with WL of 660nm have a energy of 1.879 eV
A blue photon with WL of 442nm have a energy of 2.808 eV
I see it as getting hit by a heavy weight(blue) vs. a light weight(red)
a blue led sends out fewer punches but is hitting 35% harder than red.
That I could not see in your calculations.
jubiare
Active Member
Look at the productivity of Tomato (similar to MJ, better than cucumber one) under this research
http://biology.mcgill.ca/Phytotron/LightWkshp1994/1.4 Prikupets/Prikupets text.htm
Rasser
Active Member
I can't find any specific Cannabis plants absorption charts, and since most green leaf plant charts looks the same
one could assume that the spectrum is the same for both plants but maybe the intensity nedded for cannabis is a magnitude larger.
This one from NASA looks interesting.
Rasser
Active Member
Looking at Table 3 in the link above, seams to prove that green light is not beneficial for tomato growth.
The highest yield comes from the light with the least amount of green and more red.
To bad they could not make a 0% green test run.
jubiare
Active Member
there is things to consider guys, from facts and good analysis.
HGL (don't care about the company what I care is the results) is currently using 15% green 10% blues 75% reds, this thread is on an other board and verdantgreen (the grower) has archived 1.21g/w
Things like that you want to consider, just consider
HGL (don't care about the company what I care is the results) is currently using 15% green 10% blues 75% reds, this thread is on an other board and verdantgreen (the grower) has archived 1.21g/w
Things like that you want to consider, just consider
jubiare
Active Member
That was knna thread, it would be nice to have a clarification from him .. difficult to find him around those days
have you read the whole article?
From what is my understanding, the fact that the blue has more "energy" that's for sure ... but the majority of the sun usable photons come from the 670nm, more than any other wl. So plants have adapted to that, of course, for growing.
More energy blue (more watts) doesn't mean more usable photons?
Rasser
Active Member
But you can say that if you got 100 watts of light, how do you want to distribute that?
using 20-60-20 and get 95g/m2 on 120 days or
using 10-15-75 and getting 185g/m2 on 100 days
What will happen when using 20-0-80 that is the question.
Green light may be the lubricant that makes things run smooth,
I've just not seen any evidence for that.
What I think is missing from most LED grows is intensity,
like in this test grow of a 90W(70W actual) UFO vs. a 400 watts HPS (430W actual)
70 Watts to replace 430 Watts that would be to good to be true.
The user is rating it like this:
LED wins on low energy consumption, but makes popcorn.
HPS wins on bud size and there firmness.
Taste is bit different, the HPS larger buds have longer drying time.
smell or potency is equal.
Rasser
Active Member
No I thought it was your calculations.
I will search for it.
I don't quite get it, both chlorophyll a & B have spike's at red an blue
and the absorption in the blue is higher.
Making a blue photon takes 2.8Ev where a red only takes 1.8Ev
so off course using 1W of electricity there is more photons coming out of a red LED than a blue one.
but the impact of the chlorophyll from a blue photon should be larger and produce more energy than a red one.
I'm thinking about the human skin, where visible light have no biological effect, but high energy UV has
the power to interact with the pigment and make vitamin D, and going higher
alpha(helium nuclei), beta(electrons) and gamma(high frequency photons) rays have the power to mess with the DNA of the cell.
Maybe blue light work in a deeper layer of the leaf than red.
patrikantonius
Active Member
Wanted to bump on this post, in this study : http://www.lzi.lt/tomai/97(2)tomas/97_2_tomas_str10.pdf, done in 2010 with LEDs on tomato plants, the results are the following:
for dry weight, from best to worst:
1) uv + red + blue
2) red + blue
3) red + blue + green
3) red + blue + yellow
4) red + blue + orange
I like to think that UV has little to no effect on marijuana (I cannot source this, but I think I remember reading that from a forum where knna did post, plus UV has several downsides and good reasons not to be used) so if the first result is removed the best efficiency is made with only red and blue LEDs.
patrikantonius
Active Member
I think what Knna meant is that the energy of each photon is not relevant and what's relevant is the total number of photons hitting the plant. I hate to say this but it seems to have become common knowledge that a majority of red light is more beneficial to the plant than a majority of blue. I have not seen successful growths of marijuana using only blue light while the opposite is true.
bassclef
Active Member
I remember seeing somewhere that these graphs aren't exactly accurate representing the peaks of each wavelength in ratio. It's also different for each plant, so these PAR graphs are more of a general guide rather than a rule. I don't think there is a definitive one for cannabis. I remember reading a study where they tested a number of plants and the red peak was greatest around 600-660nm in most of them. The blue peaks were there, but much lower. I'll try to find it.I don't quite get it, both chlorophyll a & B have spike's at red an blue
and the absorption in the blue is higher.
Rasser
Active Member
But is the above chart in post #93 complete, I seen carotenoid is included on some charts.
http://en.wikipedia.org/wiki/Carotenoid
http://en.wikipedia.org/wiki/Photosynthetically_active_radiation
Chlorophyll, the most abundant plant pigment, is most efficient in capturing red and blue light.
Accessory pigments such as carotenes and xanthophylls harvest some green light and pass it
on to the photosynthetic process, but enough of the green wavelengths are reflected to give
leaves their characteristic color. An exception to the predominance of chlorophyll is autumn,
when chlorophyll is degraded (because it contains N and Mg) but the accessory pigments are not
(because they only contain C, H and O) and remain in the leaf producing red, yellow and orange leaves.
http://en.wikipedia.org/wiki/Carotenoid
http://en.wikipedia.org/wiki/Photosynthetically_active_radiation
Chlorophyll, the most abundant plant pigment, is most efficient in capturing red and blue light.
Accessory pigments such as carotenes and xanthophylls harvest some green light and pass it
on to the photosynthetic process, but enough of the green wavelengths are reflected to give
leaves their characteristic color. An exception to the predominance of chlorophyll is autumn,
when chlorophyll is degraded (because it contains N and Mg) but the accessory pigments are not
(because they only contain C, H and O) and remain in the leaf producing red, yellow and orange leaves.