The far red thread

Rocket Soul

Well-Known Member
As per our resident grow-encyclopedia @Randomblame

About 3000-4000 umoles of far red per meter2, well distributed of course, so maybe 6 monos/m2 or some strip solution.
Equation works out like this:

Efficiency (umoles/s) * wattage * time (in seconds) / area (in m2)=3000 to 4000

So lets assume 3ppf/s for modern diodes run softish and 1 m2:
3*time*wattage=3000 to 4000.

Meaning if you multiply your watts with seconds you should be hitting around 1000. At 6 watts you should leave them on for some 150-200 seconds extra. If you wanted to add just a little far red to flower during your entire lights on i would rec the following: add 3w to your standard 300ish watts per meter, it will work out to about 1.5% cause youre probably more efficient on your far red side than standard whites. This should be enough to get some effect without excessive stretch. 3 watts of far red for eod treatment works out to 300-400 secs of extra time, aboout 5 mins.

Edit: adding 1.5% far red: obviously depends on what is your base spectrum, this is under the assumption of a standard 80cri led spectrum. I doubt farred is needed on hps or 90cri leds. And if youre adding 660 you may wanna add more far red but keep an eye out for stretch and shadow avoidance syndrome
 

cobshopgrow

Well-Known Member
thanks, looks like i give a lil too much, had always simply used 5min with 6w.
also enabled them 1h before lights of, but to my feeling thats allready causing some stretch.
 

Airwalker16

Well-Known Member
as far i read the emmerson effect gives diminishing returns after a certain light level (was it 600ppfd?).

UVA or blue should supress the stretch, problem is uv and blue is absorbed easily by the top leaves far red not, that really goes through the leaves.
So basically you need some kind of blue,uv under the canopy also, or, i think as bruce is saying 660nm should work also.
660nm or deep red in place of UV or blue?
 

Airwalker16

Well-Known Member
As per our resident grow-encyclopedia @Randomblame

About 3000-4000 umoles of far red per meter2, well distributed of course, so maybe 6 monos/m2 or some strip solution.
Equation works out like this:

Efficiency (umoles/s) * wattage * time (in seconds) / area (in m2)=3000 to 4000

So lets assume 3ppf/s for modern diodes run softish and 1 m2:
3*time*wattage=3000 to 4000.

Meaning if you multiply your watts with seconds you should be hitting around 1000. At 6 watts you should leave them on for some 150-200 seconds extra. If you wanted to add just a little far red to flower during your entire lights on i would rec the following: add 3w to your standard 300ish watts per meter, it will work out to about 1.5% cause youre probably more efficient on your far red side than standard whites. This should be enough to get some effect without excessive stretch. 3 watts of far red for eod treatment works out to 300-400 secs of extra time, aboout 5 mins.

Edit: adding 1.5% far red: obviously depends on what is your base spectrum, this is under the assumption of a standard 80cri led spectrum. I doubt farred is needed on hps or 90cri leds. And if youre adding 660 you may wanna add more far red but keep an eye out for stretch and shadow avoidance syndrome
I have 6x 730nm monos per 4x4.
 

Kassiopeija

Well-Known Member
as far i read the emmerson effect gives diminishing returns after a certain light level (was it 600ppfd?).
why is this so? Id like to understand more about these photosystems, why eg cant both use FR - does the energy not suffice to carry out the movement fully?
I always wondered why the Cree curve didnt fell sharply at 700... and even more so around 400... so now that we know leaves can utilize light from 300-750nm, and build biomass with it.




UVA or blue should supress the stretch, problem is uv and blue is absorbed easily by the top leaves far red not, that really goes through the leaves.
So basically you need some kind of blue,uv under the canopy also, or, i think as bruce is saying 660nm should work also.
I do it with leaf/foliage management and plant training. If you have such a dense upper canopy then the middle and bottom shoots will stretch anyway - shade avoidance. Regulates internodial length. Actually a good thing - leaves need direct light.

Or you pluck away that pesky leaf, behold how nodial count increases in veg with swazzing. or buds develop under direct light. light drives the local metabolism wherever it falls on a leaf.

The problem is that light in the 300-500nm range will always be absorbed at first contact with matter (see Video above for reference). How much penetration power has light emitted from a 3w diode or a 25w CFL? when it needs to penetrate 60cm, which is half of my tent.

Please visit the fantastic thread of @FADING-SILHOUETTE, and you can see, what under- & sidelighting can do. On some pics, it also seems evident that the middle there are less dense buds. Only where the side or underlight hit is density.

What you need instead is green light, at best 550nm. It can penetrate leaves better and does reach deeper. It sort of has the same ability like FR, and is sort of forgotten at even the state-of-the-art boards. These say our tests guarantee its the very best spectrum - but isnt this always said?

Canopy top:
1581948203800.png

Below canopy:
1581948260300.png

In natural sunlight, there's much more green than in any growlight. they concentrate too much on the 4 absorption peaks of chlorophyl.

Plants recycle leaves that dont get much light after a time. But the suns green spectrum actually penetrates so deep, trees can have many leaves and sometimes only the innermost gets self-pruned.

I dont think you would be able to grow a tree to such a natural healthy form with any kind of growlight. There would be too much going on at the top, and too less in the middle.

Even the loss of lightstrength over distance is irrelevant in nature but of tragic consequences.... the plant gets confused, doesnt know, where it is... responds by wonky form/outlook...green could solve that, esp. in veg. it would stimulate initial shoot tips even if those are blocked directly from a huge fanleave. then there would be more shoots in the same time, more nodes, less individual shooting high colas - and ultimately: more uniform buds!

Go look how healthy CFL T5 plants grow. They got everything plus the best spreaded lightsource - like the blue sky - the sky itself emits 15-30k lux which encompasses a plant with light from all directions.

Leaf color influences temperature from increased light absorption when darker. This has also a huge impact on light penetration. My personal experience is if leaves are green like grass they grow best.
 

cobshopgrow

Well-Known Member
for the Emmerson effect.
"An experiment was made in which 714 my light intensity was kept constant and that of 650 myA wvas varied. The Emerson enhancement calculated from this experiment increases with increasing intensity of 650 mg light up to a point and then saturates. "

there is probably a saturation point at which the emmerson effect isnt as strong anymore.

quoted from here, there is a nice chart at page 12 you may want to check.

shade avoidance
the basic idea is/was that the 730nm cause the shade avoidance effect which is often undesired and can be competed by UV/blue/deep red as then its simply no shade anymore for the plant.
so as you say, side, undercanopy light or pluck em.
its clear to see that 730 nm is the strongest wavelenght under a leaf, will do a measuremet and show.

i think there is a lot green allready in out white leds, not as much as the sun provide maybe, still quite some.
probably this opens a a whole can of discussions how much green light is needed and wanted.
there are some saying it reduces yield if there is too much of it.
 

cobshopgrow

Well-Known Member
this is sunlight, cloudy day, for reference.
P1030835.JPG

the spectrum i use, NO far red on.
P1030837.JPG

the spectrum below measured through a leaf (sensor covered by one leaf directly)
see the extreme bump for the far red, shade.
green is harder to interpret, you may see something.
looks like its pretty well absorbed, like the blue nd red is?
P1030838.JPG
 

Kassiopeija

Well-Known Member
As per our resident grow-encyclopedia @Randomblame

About 3000-4000 umoles of far red per meter2, well distributed of course, so maybe 6 monos/m2 or some strip solution.
Equation works out like this:

Efficiency (umoles/s) * wattage * time (in seconds) / area (in m2)=3000 to 4000

So lets assume 3ppf/s for modern diodes run softish and 1 m2:
3*time*wattage=3000 to 4000.

Meaning if you multiply your watts with seconds you should be hitting around 1000. At 6 watts you should leave them on for some 150-200 seconds extra. If you wanted to add just a little far red to flower during your entire lights on i would rec the following: add 3w to your standard 300ish watts per meter, it will work out to about 1.5% cause youre probably more efficient on your far red side than standard whites. This should be enough to get some effect without excessive stretch. 3 watts of far red for eod treatment works out to 300-400 secs of extra time, aboout 5 mins.

Edit: adding 1.5% far red: obviously depends on what is your base spectrum, this is under the assumption of a standard 80cri led spectrum. I doubt farred is needed on hps or 90cri leds. And if youre adding 660 you may wanna add more far red but keep an eye out for stretch and shadow avoidance syndrome
thanks you much for this explanation, have that bookmarked.

I plan to use FR as an EOD starting from the shift to flower. And the constant daytime FR spectrum enhancement after the stretch is mostly done and flowers build up. Therefor stretch doesn't matter to me but I want to increase the level of photosynthesis during that phase. Just addign a tad more and hoping to maximize this Emerson-effect, so I got 2 of these:


Two of their FR standalone kit

And two of their NUV 400nm, too, but since the drivers can support a total of around 15-25 (that's what the datasheet states) I ordered some more diodes.... like 10*730 3w; 10*440nm 5w; 10*660nm 5w; and still waiting on some 3w UVA.... These will shine from the topsides in 45 deg angle, they're really close to the sides.... I hope I don't fry the plants XD or the chips... I'm not really versed in it and have absolutely no instrument to measure ppfd. just a homegrower here...

The plants will be somewhat bigger plants and are under 4*75w Cree 3500k at the sides and a combination of HPS & MH lamp as centerpiece. The sidelighting LED on 4 separate channels, although I may combine the 440nm & UV.

This utter chaos defies all mathematical equation, instead it will be an experiment into senseless uncertainty :bigjoint:

IMG_20200504_014825.jpgIMG_20200504_014934.jpg

IMG_20200504_184055.jpg
this will require alot of wiring -.- will also mount add. heasinks... and I'll put only 50% of them on at a time.


The future victims, all different strains by seeds, so far none male...
IMG_20200511_184957.jpg
once I transplant they go into this tent but I only light the middle MH, and adapt up, as they grow tall.
 

Kassiopeija

Well-Known Member
So one leaf reduces the luminosity to 1/20th of what it was before. So basically what shines through is not really much in terms of being able to build anything up.

Could you perhaps take a measurement of full sunlight, when the sun is up high in the sky, unblocked & blocked by a cannabis leaf. I wonder how great the loss there is percentage-wise...?

550-560 pass also quite well, if thats defined as green not sure atm, for my spectrometer its more yellow.
I think it's where green transitions into yellow. I'm actually partially colorblind, and all the colors near that region look the same to me...

I find 550nm interesting because of this
sativa_absorption.png

it seems like plants build less substances that may absorb light from around that region... so it passes better.... so the direction I'm seeing is to increase the level of photosynthesis by giving them 550nm + Fr.

However, if experiments show it creates less mass it may be wrong. But actually I'm seeing the benefit of green more in the veg, in flower you actually want the sugar leaves to do much and since their so small it may be best to pump into them what can be pumped into them.
 

cobshopgrow

Well-Known Member
So one leaf reduces the luminosity to 1/20th of what it was before. So basically what shines through is not really much in terms of being able to build anything up.

Could you perhaps take a measurement of full sunlight, when the sun is up high in the sky, unblocked & blocked by a cannabis leaf. I wonder how great the loss there is percentage-wise...?


I think it's where green transitions into yellow. I'm actually partially colorblind, and all the colors near that region look the same to me...

I find 550nm interesting because of this
View attachment 4564079

it seems like plants build less substances that may absorb light from around that region... so it passes better.... so the direction I'm seeing is to increase the level of photosynthesis by giving them 550nm + Fr.

However, if experiments show it creates less mass it may be wrong. But actually I'm seeing the benefit of green more in the veg, in flower you actually want the sugar leaves to do much and since their so small it may be best to pump into them what can be pumped into them.
you could be about right with the 20/1, but its hard to compare.
the leaf i covered the sensor with was pretty much on the outer edge and may a tad lower then the 260 ppdf i measured at the canopy level.

i could see what a leaf absorb in natures sun, just need sun (not easy this days) and i could probably just do it with a snipped of leaf atm.

partially colorblind or not, youre right 550nm is fully green and my spectrometer is a bit misleading there.
your chart show a similar result would say, 550 is abit less absorbed then blue n red f.e., even less absorbed is 730 and further up.
interesting to see in your chart how well uva is absorbed,
would had thought its less, while i can also clearly see that all my 390-400 is absorbed well.

i have no real opinion on adding extra green and my infos are maybe a bit outdated and unprecise, you could be on to something.
as far i know migro did some tests as others did and the conclusion there was too much green means less product in the end.
i would need to look that up again tbh.

nice little veg box you have there with some very healthy plants.
 
Last edited:

hybridway2

Amare Shill
Why are poeple still questioning the oldest fact in the book is beyond me.
Great to see all you trying to make sense of it. Unfortunately it can lead to over-thinking it.
A Horticultural light needs F/r, n/ir.
The only time you don't need or want it is for rooting & is why i clone or seed sprout under 4-6k white leds.
Have compared this rooting thing against several light sources. Few yrs ago tried a Halogen. Took over a month to show roots. Almost lost my follow up run because of that test.
Having it included full time will increase your yeilds by about 30% along with much more natural growth traits & normal finishing times. It will also greatly reduce foxtailing which is one of the many examples meant by "Growth Traits".
Its just crazy this was ever up for debate to begin with & shows the lack of actual testing done by "Horticultural" Led Lighting Companies (SMFH). Swaying customers to purchase what's in the sellers best interest, not the buyer.
 

JOE GROWS

Member
Why are poeple still questioning the oldest fact in the book is beyond me.
Great to see all you trying to make sense of it. Unfortunately it can lead to over-thinking it.
A Horticultural light needs F/r, n/ir.
The only time you don't need or want it is for rooting & is why i clone or seed sprout under 4-6k white leds.
Have compared this rooting thing against several light sources. Few yrs ago tried a Halogen. Took over a month to show roots. Almost lost my follow up run because of that test.
Having it included full time will increase your yeilds by about 30% along with much more natural growth traits & normal finishing times. It will also greatly reduce foxtailing which is one of the many examples meant by "Growth Traits".
Its just crazy this was ever up for debate to begin with & shows the lack of actual testing done by "Horticultural" Led Lighting Companies (SMFH). Swaying customers to purchase what's in the sellers best interest, not the buyer.
Is amare the only company that knows how to make leds for horticulture?
 
Top