LED and BUD QUALITY

[Rocket Soul]

That's false.

Given enough 730 the plant will stretch regardless of overall blue or canopy top PPFD.

I dont really understand the statement you quoted but from what ive seen the blue response and far red response balance themselves somewhat, i dont believe far red stretch happens independently of blue, both modulate stretch.
Some guys over at riu did a test grow, sbs style, with matched ppfds; the resulting effect and yield being a respresntation of the two spectrums:
First spectrum:
4K+660nm, i think it was a mars bar light.

The second spectrum was this (or very close, this is gen 3 with some improved efficiency on the monos, the grow was gen2, same peaks but not as pronounced):

Lots of extra far red (10%) and near uv, i think they use 405nm. The result was the second spectrum (grow light australias) won yielding a couple of ounces more, with plants that was shorter than the Mars HE spectrum. If the far red stretch was independent of blue you would expect taller plants since 10% extra is alot. So it seems as the far red was balanced by the blue/violet so i do believe blue/uv and far red balance their effects.

 

[Ca++]

You wouldn't understand, I told you before to read up on the daily light integral and its relationship with plant age (ie. veg-length) and also plant height.
I also do remember indeed you've commented & discussed already on several presented studies about Cannabis leaf or canopy net photosynthesis rates or studies, which put this factor into a relationship to a harvest index. Or studies that proof how much light Cannabis can take before light-saturation or even photoinhibition sets in.

So you should already understand this but instead you choose an arbitrare 650umol of optimum PPFD because simply it served your own argumentative standpoint. It's so tiresome when all you want is merely to argumentate and then next week all you did read is already forgotten again.

You're talking rubbish to avoid the question. It's simple enough. Tell us about this industry standard of r8 1000umol. Trying to turn the conversation to something else is futile, as DLI is so basic you have never needed to tell me to look it up, unless I missed some occasion you didn't get the right answer yourself.
Do keep in mind I'm only back on this thread because someone posted I want to listen to. I don't follow your posts in any way, but avoid them.

 

[Ca++]

That's false.

Given enough 730 the plant will stretch regardless of overall blue or canopy top PPFD.

If you are going to argue, bring some proof. Otherwise it's just more trolling.

You won't be back

 

[Ca++]

I dont really understand the statement you quoted but from what ive seen the blue response and far red response balance themselves somewhat, i dont believe far red stretch happens independently of blue, both modulate stretch.
Some guys over at riu did a test grow, sbs style, with matched ppfds; the resulting effect and yield being a respresntation of the two spectrums:
First spectrum:
4K+660nm, i think it was a mars bar light.

The second spectrum was this (or very close, this is gen 3 with some improved efficiency on the monos, the grow was gen2, same peaks but not as pronounced):
View attachment 18911534

Lots of extra far red (10%) and near uv, i think they use 405nm. The result was the second spectrum (grow light australias) won yielding a couple of ounces more, with plants that was shorter than the Mars HE spectrum. If the far red stretch was independent of blue you would expect taller plants since 10% extra is alot. So it seems as the far red was balanced by the blue/violet so i do believe blue/uv and far red balance their effects.

This is a very under studied area, so making hard and fast statements would be thuleish. The two cannabis stretch regulators at the blue end of the spectrum, are phototropin and cryptochrome. Together they have a greater control over stretch than the red photochromes. The reds don't cause stretch, they stop stretch. With 730 we take the break off. Allowing stretch. What we actually get, is very much controlled by the blue.

Being an evolving field, we keep learning more. In today's practical terms, you can balance blue against red, to change the stretch. Even without FR. I think you probably know this, without being told.

 

[Rocket Soul]

This is a very under studied area, so making hard and fast statements would be thuleish. The two cannabis stretch regulators at the blue end of the spectrum, are phototropin and cryptochrome. Together they have a greater control over stretch than the red photochromes. The reds don't cause stretch, they stop stretch. With 730 we take the break off. Allowing stretch. What we actually get, is very much controlled by the blue.

Being an evolving field, we keep learning more. In today's practical terms, you can balance blue against red, to change the stretch. Even without FR. I think you probably know this, without being told.

Stretch is a complicated phenomena, depending on a variety of factors, some are with in the realm of light, some are environment related.
You can also question whats the definition of stretch; actual tallness of the plant or internode length.

As for light and stretch and as far as i know from reading horti science online and books (youre not far from being right here ):

There is the Pf/Pfr part which youve mentioned: red light (and far red) feeds into two systems depending on nm: under 700nm feeds Pf and over 700 feeds Pfr. The balance of the two determines one part of the stretch (dont ask me how much, i dont know and havent found science on it): the higher the ratio of Pfr to Pf the more stretch. It helps to think of why, what does this give the plant. Far red is very good at penetrating thru the cannopy, red not so much, infact its the most easiest absorbed by the plant, and within the red spectrum: 680nm is the easiest absorbed by the plant. So as you travel down thru the cannopy the ratio of far red to red increases: the plant uses this ratio to understand what part of the plant is in shade lower down down in the cannopy. So its not exactly the far red that causes stretch, its the realtionship between red and far red; which most people simplify as 660 to 730 ratio. So youre partially right that red/660 inhibits stretch in this case but its not the whole story.
There is also the blue to red ratio: the higher the red in comparison to blue the stretchier the plant. In this case red actually will cause stretch. Im not a 100 percent if you have to bunch together red and far reds when assessing this aspect of stretch; im not even sure if this can be studied effectively since far red has its own effect on stretch: it would be a somewhat tricky experiment to design. Nor is it clear if sub 700nm red all have the same effect on stretch, or even if all blues/violets have the same stretch control effect. My suspicion is that the further you get towards the end of the par range (or beyond it) the higher the effect of stretch stimulation/inhibition, but this just my own suspicion.
Theres more; the green response: some say green has no effect on cannabis morphology but it seems to have an effect at least in some other plants. The part which is interesting to stretch is that green will inhibit or reverse the blue response, canceling out its anti stretch effect (though i have to admit that i still cant find the paper where i read this). The green response can also be seen as something that informs the plant about being somewhere inside the cannopy rather than top cannopy.
And still, there is more: intensity, more intensity less stretch, less intensity more stretch as the plants tries to reach for the light.
Yet another suspicion i have : the lower the intensity the more effect the spectrum has on growth patterns. This comes partially from investigations into the Emmerson effect: its pronounced in low light conditions (ive seen quoted less than 150ppfd) and it goes down in higher light intensities. Another thing indicating this (again anecdotal, sorry) is auto grows versus photoperiod grows. In our own photo grow spectrum tests (800-1000ppfd) the difference between 3000k 80cri, 2700k 90cri and 2700 90 cri + 660 (red AF!) has been very little, sometimes one side wins sometimes the other. Stretch has been fairly similar even though the 660/730 ratio has been quite different.
Auto grows give you the possibility to flower in lower intensity while giving the same total amount of light (DLI) per day. Ive seen some astonishing auto grows with 2700k 90cri + red sup at low intensity; around 15 w per square foot producing almost 50g / square foot. Yet when growing photos with traditional intensity (around 30w per square foot) the results where not very different from just plain white, kinda meh. Also when it comes to blurple, a very red heavy light, it seems like the last proponents come from the autogrowing world. I will happily admit that i dont have any solid proof of this, but its good to make educated guesses and speculations as long as you see them as only that; it can guide you towards situations and experiments that actually give you something solid.

Emmerson effect: this is the "why" people seem to want to add a proportion of far reds to the traditional 660nm red supplement. Emmerson found that activating both Pf and Pfr under certain conditions gave more photosynthetic output (measured in change in CO2 in the grow chamber; CO2 being the indicator that theres been photosynthesis) than the sum of the two on their own. This being especially pronounced when the Pf red and the Pfr red was about 50 nms apart (best results was using 680nm and 730nm iirc).
Theres a organic chemistry explanation which is somewhat beyond what i understand or can explain; afaik its down to the two systems each doing one part of the photosynthetic chemistry; Pf doing carbon binding and Pfr doing something to get rid of an electron somewhere in the reaction. So when both these wavelengths being present at the same time the process runs smoother. I cant really say how true this is, how much effect there is at what intensity only that its relatively higher the lower the intensity. So this is why it seems to me like you can add far red, without causing yield loss or stretch, if you dont change the ratios of pf/pfr activation.

This is the essence of the "its complicated" side; its not about what you add, its about you add in relation to whats there already in the spectrum, along with the actual intensity. I know, its not very satisfying as it doesnt make things easier but this is what i belive to be closest to that elusive truth. This is also why i tank that paper; to me it only shows that the shade avoidance syndrome is real, as we already know, not the biggest whoop of all times, and definitely not an end of all discussion regarding far red in flower.

 

[JKD]

Not on cannabis, but:

“In this study we investigated how far red light interacts with blue light to regulate extension growth, leaf chlorophyll concentration and subsequent flowering of ornamental seedlings. In particular, we wanted to determine whether including a moderately high intensity of blue light could nullify the effects of far red on stem elongation without inhibiting flowering.”

LEDs: Blue & Far-Red Light

4/1/2019 Yujin Park & Erik Runkle

www.growertalks.com

 

[Crooked8]

Not a single brown led 'calmag' spot in sight.

Show me more healthy led grown plant please? crooked8 need not apply with his NA$A budget

Not another troll pic

 

[LostTribe]

I for one am not liking LED. Tossed the Mars fc-e4800 back in the box after 2 blooms. This hlg knock off quantum board nearly just killed some healthy plants too, so it might be getting tossed next.

Busted the old reliable Hortilux back out.

 

[exoticrobotic]

Do you use chem or organic nutes @LostTribe @Crooked8 ?

 

[LostTribe]

Do you use chem or organic nutes @LostTribe @Crooked8 ?

currently salts.

 

[exoticrobotic]

I am sick in the head to be amused with all this talk of phototropin, cryptochrome, ppfd, umol, pf, pfr, red, far red etc when most of the led grown plants look so shit awful unhealthy



Please excuse me

e2a As usual this doesn't apply to crooked8 as he grows looking plants under leds

Maybe @Crooked8 can help explain wtf is up?

 

[exoticrobotic]

I'd open a led and general plant health thread but i've given up on them apart from as an expensive veg light.

They obv work to veg and flower plants but i dont want dehydrated leopards/zebras

 

[Ca++]

The balance of the two determines one part of the stretch (dont ask me how much, i dont know and havent found science on it

what i understand or can explain; afaik its down to the two systems each doing one part of the photosynthetic chemistry; Pf doing carbon binding and Pfr doing something to get rid of an electron somewhere in the reaction

It's my understanding that the Pfr is interfering with the Pr's ability to complete processes that limit stretch. Our accounts could link together as such.

 

[Ca++]

I'd open a led and general plant health thread but i've given up on them apart from as an expensive veg light.

They obv work to veg and flower plants but i dont want dehydrated leopards/zebras

But you know it doesn't have to be that way. Even if you can only find one example in the whole world. Though lets be fair... we know he wheels away the DE's before taking pics lol

 

[Normannen]

I for one am not liking LED. Tossed the Mars fc-e4800 back in the box after 2 blooms. This hlg knock off quantum board nearly just killed some healthy plants too, so it might be getting tossed next.

Busted the old reliable Hortilux back out.

i'll teke it off you if you don't wan it

 

[Normannen]

The best option would be to make your own led, as in assemble the chips on the board yourself.
it involves knowing what each chip does
spending money on good quality pretested chips
the alternative is to buy cheap chinese counterfeit and test them one by one
then you need to have basic knowledge of circuitry and electronics (not hard when it comes to LED tho)
Soldering is the fun part in terms of technical , but I guess I'm jsut a weirdo who likes melting stuff (maybe not completely alone on that one here...)
The wiring is as easy as as any electrical wiring (for me, some people need the help of a professional or a friend with the knowhow, and it should be that way for safety's sake)
I probably forgot something
but it's a helluva fun DIY project

 

[Rocket Soul]

It's my understanding that the Pfr is interfering with the Pr's ability to complete processes that limit stretch. Our accounts could link together as such.

Where are you reading this?

I also apologize for being sloppy, its of course Pr and Pfr, not Pf and Pfr.
Pr and Pfr is two states of the phytochrome receptor protein. When it processes photosynthesis it has to go thru both forms to complete the process and the creates sugar and O2 out of CO2 and H2O. Each form has its function in this process, it has to go thru both states to complete the chemical process. Having access to both red and far red means that this process get faster and more efficient (emmerson effect). But the phytochrome also does more than this, it also measures night and day (nightfall means Far red > red light) and if the plant is in the shade (again Far red > red). So its a bit unexact to say that the Pr completes process that limit stretch; this whole stretch thing is kind of a byproduct to how the plant does red light photosynthesis: Pr and Pfrs main function is this and not photosensing.

Here are some primers on this if you like.

https://bio.libretexts.org/Bookshel... to red light converts,the inactive form (Pr).

photosystems I and II

photosystems I and II - pigment systems I and II, PSI and

www.botanydictionary.org

 

[Normannen]

As I see it Pfr seems like it's interfering with Pr because it needs an equivalent volume of photons to "compete" with Pb (EDIT: Phytochrome A, I said b because of blue ) because as someone said above the balance of the two determines season and therefore stretch induced by hormonal pathways activating

so your lights should have an equivalent FR to B ratio or you are inhibiting stretch. But do you want it?

 

[Crooked8]

Do you use chem or organic nutes @LostTribe @Crooked8 ?

I used to use both but our results are better with salt based

 

[Crooked8]

I am sick in the head to be amused with all this talk of phototropin, cryptochrome, ppfd, umol, pf, pfr, red, far red etc when most of the led grown plants look so shit awful unhealthy



Please excuse me

e2a As usual this doesn't apply to crooked8 as he grows looking plants under leds

Maybe @Crooked8 can help explain wtf is up?

I will make it simplified as i can. Plants have an easier time when their life is easy. Life is easy at high rh, medium light levels and delicate oscillation. Plants will thrive. Under hps we challenge these plants for sure, but nowhere near as challenging as we make it under commercial grade leds. Especially at 50-55%rh with lots of wind. That puts extra demand on them. The main reason people struggle is because they slam their plants under intense light levels without meeting all other needed cardinal parameters. If you increase photons, you need to increase feed, co2, air movement, potentially irrigation frequency etc. imo the cultivation world is having a hard time matching the other environmental factors that need to be more extreme and consistent to match up with more extreme light. This is my take so far anyway.