LED and BUD QUALITY

[Prawn Connery]

Like I mentionned, I never heard anyone talk about Emerson effect before you so that's kinda funny as you explained it like someone who just discovered it. Far red is photosynthetic and it is part of the photosynthesis. UV is not. actually uv is totally useless except for UVB and the only reliable UVB light are T5 , thats why I said commercials are not ready for it. Now the hype is on far red but thing is you better spend on more effective photons! Why? Because far red cause morphologic change in plant and it doesnt benefit production in cannabis as it would with leafy greens. Leggy and stretchy plant are not desirable in my book.And UV damages plants thats just unproductive.

Photosynthetically-active radiation, UV-A and UV-B, causes both common and specific damage and photoprotective responses in the model liverwort Marchantia polymorpha subsp. ruderalis

We studied the effects of different radiation treatments on the physiology and UV-absorbing compounds of the model liverwort Marchantia polymorpha subsp. ruderalis. Starting from gemmae, samples were exposed to five radiation treatments: low photosynthetically active radiation (PAR), low PAR+...

pubs.rsc.org

Wrong. it does have far red but no UV. And wrong again if you had read , they suffered from drought I forgot one irrigation. Theres is no way my feed lack of nitrogen.
View attachment 18963185

View attachment 18963192

Isn't it always the way? This thread was dead for a while there and now it has sprung to life again. Some of the things I wanted to address have already been addressed, but I'll go over them again briefly.

@Rocket Soul mentioned this, and it was the first thing I picked up on. @weedemart, you should have picked up on this, too, because it was a very obvious mistake.

This is WRONG. The scale is out by over 50nm. I can see why someone might think that Far Red is photosynthetic after looking at this pigment absorption graph, but like so many things the dodgy Chinese LED makers publish, it's just bullshit.

This is what the pigment chart should look like. There is a caveat (there always is) and that is you will see a lot of variation in these graphs as to where, exactly, each peak is, but they are mostly in the ballpark. Some of the discrepancy comes from which solvents they use to dissolve the chlorophyll and other pigments to measure absorption. There are a few papers out there arguing that chlorophyll absorption is much bluer (the peaks are further to the left, into the shorter wavelengths) than most absorption graphs show. I'll save that for a different debate.

I chose this graph because it shows Pr and Pfr in relation to Chl A and B, as well as anthocyanins. Note peak absorption of Pfr – this is why the Emerson and other effects peak at around 720-730nm and then drop off. Note that Pfr also goes into the UV zone – most graphs don't show this.

But also of interest is the Pr line that goes into the near-UV zone – notably around 400nm. There is a lot going on at these wavelengths that are not typically covered by horticultural LEDs.

The Emerson Effect initially brought to light (pun intended) the possibility of there being two light-reactive centres, or photosystems, and indeed this was the case. At the time of Emerson's research, there was thought to be only one – Photosystem 1. That's why PS2 comes before PS1 – because PS1 was discovered first, even though it is second in line in the reaction centres.

I will revise what I said about Far Red light not being photosynthesised, because a very small amount of it is, but this is a quirk of ascribing 700nm to PS1 as the actual wavelengths it absorbs extend a small way beyond 700nm. But my earlier assertion that the electron chain only goes in one direction is still true: at some point just beyond 700nm, individual photons do not carry enough energy to excite an electron to a high enough state to photosynthesise.

The Emerson Effect, however, is due to the quenching effect of Far Red light that lowers the temperature of the reaction centres (notably PS1) which allows greater absorption of longer wavelengths in the red part of the spectrum. It is now believed the Emerson effect also increases absorption of shorter wavelengths in the blue region.

So, Far Red is photosynthesised but only to a very minor extent. Far Red increases the quantum yield of photosynthesis by lowering the temperature of the reaction centres.

That is the Emerson Effect.

As for the Spider Farmer spectrum itself, there is no way they use 760nm diodes. And if they did. they would be fucking idiots because 760nm diodes are much less efficient than 725-730nm diodes, and at 760nm nearly all the benefits of Far Red are gone – because hardly any of it is absorbed.

Also, where's the 760nm peak in the graph? There isn't even a 720m peak. The graph does show a slightly longer Far Red tail than typical LEDs indicative of the addition of a VERY small number of 730nm diodes, but this light has only around 2-3% Far Red.

How do I know? Does this graph look familiar? This is a Mars Hydro (same company as Spider Farmer) we tested on an $80,000 goniometer. Yes, I have access to a goniometer so can test these things for real. OK, credit where it's due: LED Teknik does the testing for us. They are our strategic partner in LED fixture design.

BTW, that's the true efficiency there: 2.57 umol/j – so don't listen to any bullshit Chinese claims about "2.9 umol/j" or whatever.

So the main reason your plants weren't stretching is due to there being very little Far Red and over 20% blue.

 

[weedemart]

Isn't it always the way? This thread was dead for a while there and now it has sprung to life again. Some of the things I wanted to address have already been addressed, but I'll go over them again briefly.

@Rocket Soul mentioned this, and it was the first thing I picked up on. @weedemart, you should have picked up on this, too, because it was a very obvious mistake.

This is WRONG. The scale is out by over 50nm. I can see why someone might think that Far Red is photosynthetic after looking at this pigment absorption graph, but like so many things the dodgy Chinese LED makers publish, it's just bullshit.
View attachment 18964088

This is what the pigment chart should look like. There is a caveat (there always is) and that is you will see a lot of variation in these graphs as to where, exactly, each peak is, but they are mostly in the ballpark. Some of the discrepancy comes from which solvents they use to dissolve the chlorophyll and other pigments to measure absorption. There are a few papers out there arguing that chlorophyll absorption is much bluer (the peaks are further to the left, into the shorter wavelengths) than most absorption graphs show. I'll save that for a different debate.

I chose this graph because it shows Pr and Pfr in relation to Chl A and B, as well as anthocyanins. Note peak absorption of Pfr – this is why the Emerson and other effects peak at around 720-730nm and then drop off. Note that Pfr also goes into the UV zone – most graphs don't show this.

But also of interest is the Pr line that goes into the near-UV zone – notably around 400nm. There is a lot going on at these wavelengths that are not typically covered by horticultural LEDs.
View attachment 18964090

The Emerson Effect initially brought to light (pun intended) the possibility of there being two light-reactive centres, or photosystems, and indeed this was the case. At the time of Emerson's research, there was thought to be only one – Photosystem 1. That's why PS2 comes before PS1 – because PS1 was discovered first, even though it is second in line in the reaction centres.

I will revise what I said about Far Red light not being photosynthesised, because a very small amount of it is, but this is a quirk of ascribing 700nm to PS1 as the actual wavelengths it absorbs extend a small way beyond 700nm. But my earlier assertion that the electron chain only goes in one direction is still true: at some point just beyond 700nm, individual photons do not carry enough energy to excite an electron to a high enough state to photosynthesise.

The Emerson Effect, however, is due to the quenching effect of Far Red light that lowers the temperature of the reaction centres (notably PS1) which allows greater absorption of longer wavelengths in the red part of the spectrum. It is now believed the Emerson effect also increases absorption of shorter wavelengths in the blue region.

So, Far Red is photosynthesised but only to a very minor extent. Far Red increases the quantum yield of photosynthesis by lowering the temperature of the reaction centres.

That is the Emerson Effect.

As for the Spider Farmer spectrum itself, there is no way they use 760nm diodes. And if they did. they would be fucking idiots because 760nm diodes are much less efficient than 725-730nm diodes, and at 760nm nearly all the benefits of Far Red are gone – because hardly any of it is absorbed.

Also, where's the 760nm peak in the graph? There isn't even a 720m peak. The graph does show a slightly longer Far Red tail than typical LEDs indicative of the addition of a VERY small number of 730nm diodes, but this light has only around 2-3% Far Red.
View attachment 18964098

How do I know? Does this graph look familiar? This is a Mars Hydro (same company as Spider Farmer) we tested on an $80,000 goniometer. Yes, I have access to a goniometer so can test these things for real. OK, credit where it's due: LED Teknik does the testing for us. They are our strategic partner in LED fixture design.
View attachment 18964099
BTW, that's the true efficiency there: 2.57 umol/j – so don't listen to any bullshit Chinese claims about "2.9 umol/j" or whatever.

So the main reason your plants weren't stretching is due to there being very little Far Red and over 20% blue.

Yes theres is far red diode I can see them on board.

And 700-750nm is photosynthetic I dont know why you are trying to argue with that you can find this everywhere. I could find a lot of litterature and graph thats prove it.It's now called the ePAR range or wtv and their even marketing epar range sensor. The graph above is totally legit.

My point is... you need far red. Its obvious.You gain from having far red in your spectrum. But its not a game changer and you wont benefit adding more far red as it cause undesirable morphologic change.But you will benefit from other wavelenght like blue red and everything between. Far red is just an old-new hype.

The emerson effect can be simply explained this way; the energy sums of all wavelenght combined is greater than an equal intensity of a single wavelenght(i.e; red). And it's old data ,old theory.That how the idea of a full spectrum is born and the WHY it is better than blurple led. Now we are modern we recognize the role of far red in the par range and we can conclude that the emerson effect was just a concept because far red was excluded from the par range.

But the main thing.... is still effiency above everything.And far red is not an efficient photon with led

 

[Prawn Connery]

Like I mentionned, I never heard anyone talk about Emerson effect before you so that's kinda funny as you explained it like someone who just discovered it. Far red is photosynthetic and it is part of the photosynthesis. UV is not. actually uv is totally useless except for UVB and the only reliable UVB light are T5 , thats why I said commercials are not ready for it. Now the hype is on far red but thing is you better spend on more effective photons! Why? Because far red cause morphologic change in plant and it doesnt benefit production in cannabis as it would with leafy greens. Leggy and stretchy plant are not desirable in my book.And UV damages plants thats just unproductive.

Photosynthetically-active radiation, UV-A and UV-B, causes both common and specific damage and photoprotective responses in the model liverwort Marchantia polymorpha subsp. ruderalis

We studied the effects of different radiation treatments on the physiology and UV-absorbing compounds of the model liverwort Marchantia polymorpha subsp. ruderalis. Starting from gemmae, samples were exposed to five radiation treatments: low photosynthetically active radiation (PAR), low PAR+...

pubs.rsc.org

Now you know what the Emerson Effect is, what about your claim that UV does not contribute to photosynthesis?

Also untrue. UV includes UVA up to 400nm. Have a look at the absorption graphs above and you will see that UVA most definitely IS absorbed by Chl A and Chl B (but especially Chl A, which is responsible for around 2/3 of photosynthesis, Chl B making up the remaining 1/3).

You probably think that only UVB has the desired morphological effects that promote secondary metabolite production because of the UVR8 receptor that protects plants from photo-oxidative DNA damage.

Again, you would be wrong. Here is the UVR8 graph – pay attention to the scale detail. In fact, UVR8 absorbs past 400nm, which is why blue light can also trigger the same morphological response – just not as strongly.

So we see the addition of UVA – especially around 400nm, where it is also photosynthetic – can have beneficial effects, including the production of secondary metabolites which include cannabinoids.

This is why I get into arguments with people who claim UVA has no effect on cannabinoid production, because they are testing the wrong parts of the spectrum. You can see in the THC testing I posted earlier that UVB can send THC backwards if you use too much, while UVA sends it forwards if you use it around 400nm – which is exactly what I do with the lights I design.

You are correct that fluorescent light is a good, reliable (and cheap) source of UVB, but a I've already proven, you don't need UVB.

The Nichia 405nm diodes we use are over 70% efficient! That is at least twice as efficient as any fluoro. LEDs last longer, too.

And btw if you want live proof of far red disadvantage in certain situation; try start from seed directly under strong light with far red. Do a side by side with T5 6400k spectrum. 100% guarenteed your seeds will end up less stretchy with T5. Why? No far red!And no UV.

I don't know why you wrote this when you know T5s emit UV.

T5s also emit Far Red, so you were wrong on both counts. Just sayin.

Here's a CFL I tested which uses the same plasma and phosphor as a T5. Yes, I also have a hand-held spectrometer.

How much time plant were exposed to uvb per day ?

I plan to do 15min midcycle last 3 weeks, what you think. First time experiment with reptisun

Why would you use the T5 in the last 3 weeks of flowering when cannabinoid production peaks around 2-3 weeks BEFORE harvest?

There would be more benefit to using it right from the start of flowering. Using UVB in small doses of 15-30 minutes would likely be beneficial, To answer your question, the UVB/reptile bulbs used in the tests I did where we saw THC go backwards were on for 6 hours a day – way too much!

Again, you are better off using a small amount of UVA over a longer period than UVB. Not bro science - I've actually tested this. I have't tested small amounts of UVB because I see no point adding a light that isonly going to be on for 15-30 minutes when I can add 405nm diodes that I can use the full 12 hours.

Think of it this way: in Nature (outdoors), at what point is UV highest during the flowering cycle? At the beginning. It's even higher during veg.

And this is another issue I have with scientists testing UVB on plants - their methodology is not correct, IMO, because they don't normally grow cannabis! Even Bugbee, who only grows hemp. but that's another story!

 

[weedemart]

Now you know what the Emerson Effect is, what about your claim that UV does not contribute to photosynthesis?

Also untrue. UV includes UVA up to 400nm. Have a look at the absorption graphs above and you will see that UVA most definitely IS absorbed by Chl A and Chl B (but especially Chl A, which is responsible for around 2/3 of photosynthesis, Chl B making up the remaining 1/3).

You probably think that only UVB has the desired morphological effects that promote secondary metabolite production because of the UVR8 receptor that protects plants from photo-oxidative DNA damage.

Again, you would be wrong. Here is the UVR8 graph – pay attention to the scale detail. In fact, UVR8 absorbs past 400nm, which is why blue light can also trigger the same morphological response – just not as strongly.

View attachment 18964100

So we see the addition of UVA – especially around 400nm, where it is also photosynthetic – can have beneficial effects, including the production of secondary metabolites which include cannabinoids.

This is why I get into arguments with people who claim UVA has no effect on cannabinoid production, because they are testing the wrong parts of the spectrum. You can see in the THC testing I posted earlier that UVB can send THC backwards if you use too much, while UVA sends it forwards if you use it around 400nm – which is exactly what I do with the lights I design.

You are correct that fluorescent light is a good, reliable (and cheap) source of UVB, but a I've already proven, you don't need UVB.

The Nichia 405nm diodes we use are over 70% efficient! That is at least twice as efficient as any fluoro. LEDs last longer, too.


I don't know why you wrote this when you know T5s emit UV.

T5s also emit Far Red, so you were wrong on both counts. Just sayin.

Here's a CFL I tested which uses the same plasma and phosphor as a T5. Yes, I also have a hand-held spectrometer.
View attachment 18964103



Why would you use the T5 in the last 3 weeks of flowering when cannabinoid production peaks around 2-3 weeks BEFORE harvest?

There would be more benefit to using it right from the start of flowering. Using UVB in small doses of 15-30 minutes would likely be beneficial, To answer your question, the UVB/reptile bulbs used in the tests I did where we saw THC go backwards were on for 6 hours a day – way too much!

Again, you are better off using a small amount of UVA over a longer period than UVB. Not bro science - I've actually tested this. I have't tested small amounts of UVB because I see no point adding a light that isonly going to be on for 15-30 minutes when I can add 405nm diodes that I can use the full 12 hours.

Think of it this way: in Nature (outdoors), at what point is UV highest during the flowering cycle? At the beginning. It's even higher during veg.

And this is another issue I have with scientists testing UVB on plants - their methodology is not correct, IMO, because they don't normally grow cannabis! Even Bugbee, who only grows hemp. but that's another story!

No friend you are wrong on this one. UVA is useless because it's not strong enought to stress the plant but yes it will have some morphologic adaptation but once again undesirable one like lower mass and stunted growth. UVA is a total waste of energy and productivity.T5 doesnt emit enought UV or far red to be considered, except the one that was made for reptiles(UVB range t5)

and the reason UVB win hands down against UVA is because it's so strong for plant that they cant adapt.
It's a induced-stress. If well applied at the right time, it wont affect yield but it could add some bag appeal and cannabinoids compounds. But if applied too much your plant will simply stop grow because they are trying to survive this UVB radiation.

UVB radiation are at the highest point at noon outdoor. it follow a bell curved shape.

I never tried UVB , but I've read a lot on the subject. Going to experiment soon.

 

[Prawn Connery]

Yes theres is far red diode I can see them on board.

And 700-750nm is photosynthetic I dont know why you are trying to argue with that you can find this everywhere. I could find a lot of litterature and graph thats prove it.It's now called the ePAR range or wtv and their even marketing epar range sensor. The graph above is totally legit.

My point is... you need far red. Its obvious.You gain from having far red in your spectrum. But its not a game changer and you wont benefit adding more far red as it cause undesirable morphologic change.But you will benefit from other wavelenght like blue red and everything between. Far red is just an old-new hype.

The emerson effect can be simply explained this way; the energy sums of all wavelenght combined is greater than an equal intensity of a single wavelenght(i.e; red). And it's old data ,old theory.That how the idea of a full spectrum is born and the WHY it is better than blurple led. Now we are modern we recognize the role of far red in the par range and we can conclude that the emerson effect was just a concept because far red was excluded from the par range.

But the main thing.... is still effiency above everything.And far red is not an efficient photon with led

Mate, you're just parroting what you saw on an old Bugbee video. "ePAR" may arse – we were putting Far Red diodes into our lights years before Bugbee came up with that term to sell his new Apogee light meters.

It is clear you don't understand the science and are not willing to learn. I tried to explain the science simply to you, and you still do't get it.

So you do whatever you want to your plants – I don't really care. But I'm still going to call you out when I see bullshit, because growers with less experience shouldn't be getting their advice from someone like you who just parrots information he doesn't understand.

Far Red is an efficient photon. Ours are 3.5 umol/j, even at only 55% efficiency. Look up Planck's Law and you will understand why.

The big benefit of Far Red comes from morphological leaf expansion that increases the surface area of the chloroplasts that drive photosynthesis. Not once have I heard you mention this. Shade avoidance has two main components, one of which is internodal elongation which can be reversed using UV whilst retaining the other component, larger leaf area.

Other benefits of Far Red are the Emerson Effect and light penetration. Here are some more light readings I did showing canopy penetration:

Top canopy

Mid canopy

Bottom canopy

Basically, we're doing this shit for real – you are not.

 

[Prawn Connery]

No friend you are wrong on this one. UVA is useless because it's not strong enought to stress the plant but yes it will have some morphologic adaptation but once again undesirable one like lower mass and stunted growth. UVA is a total waste of energy and productivity.T5 doesnt emit enought UV or far red to be considered, except the one that was made for reptiles(UVB range t5)

and the reason UVB win hands down against UVA is because it's so strong for plant that they cant adapt.
It's a induced-stress. If well applied at the right time, it wont affect yield but it could add some bag appeal and cannabinoids compounds. But if applied too much your plant will simply stop grow because they are trying to survive this UVB radiation.

UVB radiation are at the highest point at noon outdoor. it follow a bell curved shape.

I never tryed UVB , but I've read a lot on the subject. Going to experiment soon.

It's like arguing with someone at the Special Olympics.

Sunlight contains only a fraction UVB compared to UVA, so you are arguing against Nature.

Good luck with that!

Yeah, UVB photo-oxidises cannabinoids (as does ALL light, but UVB does it faster, because it has more energy), so let's use it in the last three weeks to reduce our THC content so that we can increase our "bag appeal".

You're so uneducated, you can't even see the contradictions in your own arguments.

That's enough, I've wasted too much of this day on you. Hopefully others will benefit.

 

[weedemart]

Mate, you're just parroting what you saw on an old Bugbee video. "ePAR" may arse – we were putting Far Red diodes into our lights years before Bugbee came up with that term to sell his new Apogee light meters.

It is clear you don't understand the science and are not willing to learn. I tried to explain the science simply to you, and you still do't get it.

So you do whatever you want to your plants – I don't really care. But I'm still going to call you out when I see bullshit, because growers with less experience shouldn't be getting their advice from someone like you who just parrots information he doesn't understand.

Far Red is an efficient photon. Ours are 3.5 umol/j, even at only 55% efficiency. Look up Planck's Law and you will understand why.

The big benefit of Far Red comes from morphological leaf expansion that increases the surface area of the chloroplasts that drive photosynthesis. Not once have I heard you mention this. Shade avoidance has two main components, one of which is internodal elongation which can be reversed using UV whilst retaining the other component, larger leaf area.

Other benefits of Far Red are the Emerson Effect and light penetration. Here are some more light readings I did showing canopy penetration:

Top canopy
View attachment 18964104
Mid canopy
View attachment 18964105

Bottom canopy
View attachment 18964106


Basically, we're doing this shit for real – you are not.

Then you should know that not all photons are equals in term of energy!
I dont care you are doing it for real from a nasa cabinet.
I did it for real from one of the biggest place with people like you and they knew absolutely nothing except their baked science from their diploma. Powdery mildew,insects,algae,fungus everywhere.

Listen,I respect you but you dont impress me.

 

[Prawn Connery]

Should I reduce Ca inputs in the final weeks? The plants struggle to take it, so should I counter with more, or just let it be. I reuse coco, so do have reason to keep adding at least some. While too much can actually hinder uptake, a bit like soup.
Random.. but it's been playing on my mind.

I see this a lot in coco grows, especially under LED, where Ca deficiency shows up half-way through flower when PK is introduced, as it competes with calcium.

As you know, calcium is central to cell production and plants need it throughout all stages of growth. If you re-use your coco – as I do (but usually only once) – salts will build up and you may have an abundance of potassium in there, and very little available calcium. So when I re-use coco, I go heavy on the Cal-Mag at the start to flush out the excess K. I also use a mild N, Ca, Mg additive all the way through flower until the last 1-2 weeks.

It also depends on the strain, as sativas are less likely to show a Ca deficiency than indicas, which have more leaf mass. If you defoliate (not "you", personally, but generic you), then you strip out al the plant's nutrient reserves, including Ca, Mg and N. This can exacerbate a Ca deficiency in late flower.

 

[Prawn Connery]

Then you should know that not all photons are equals in term of energy!
I dont care you are doing it for real from a nasa cabinet.
I did it for real from one of the biggest place with people like you and they knew absolutely nothing except their baked science from their diploma. Powdery mildew,insects,algae,fungus everywhere.

Listen,I respect you but you dont impress me.

Except I don't have a degree, I'm not a scientist, and everything I have learned is through decades of growing experience and self-education.

I don't do this to impress people like you. I do this to help people who deserve it.

 

[Prawn Connery]

Have you tried calcium nitrate and mgs instead of calmag?

My calmag uses calcium nitrate and magnesium nitrate. 3:3:1 N:Ca:Mg. I think GH calmag uses calcium carbonate and epsom salts, as do others. I don't use them.

 

[JKD]

Something to consider with reptile lamps is even a high output 14% UVB lamp (Arcadia) actually produces more than twice as much UVA than UVB @ 30%.

 

[weedemart]

Something to consider with reptile lamps is even a high output 14% UVB lamp (Arcadia) actually produces more than twice as much UVA than UVB @ 30% UVA.

Yes I know. I'm looking for migro uvb t5 tube. a bit expensive tho.

 

[Prawn Connery]

While content of far red in the sun, and its lack of inducing insane stretch, is an important point to note i think that its hard to make a direct comparison here, since light intensity is also stretch inhibiting, and sun light is easily twice as intense as we use for indoor growing.

Be careful with that. While sunlight peaks around 2000 umol/j, it is only a peak around mid-day. DLI, as you know, is the real metric. Plants are only exposed to such high light levels for an hour or two a day.

What i can say from our first try with the GLA/prawn strips is that the added far red seems to be balance someway, no real difference in stretch with our other trays. That grow finishes in a few weeks, still not updated with pics; my growbuddy makes me jump thru a lot of hoops to post anything; theres a lot of paranoia up there in the grow. Got a few pics from midway thru and the beginning but i need to figure out a way to post similar as external links that i can disable; can only leave pics up for a bit of time according my buddy.

I keep saying to people the extra Far Red won't induce stretch, and that is due to the UVA at the other end. I'm glad you are now seeing this for yourself

Prawn: from one thing to another, especially here while talking about Emmerson: have you ever evaluated red sup at 680nm? We added some to juice up our 2700k 90cri blux eb strips and it is looking real good...
Obviously there would be some efficiency loss in 680nm diodes, but at what point would that be cancelled out by being more aligned to plants spectrum needs?

If efficiency were not a concern, then that's what we'd be using, but the 660 bins we are getting are closer to 670nm, as you might be able to see from this report, so that's the best we can do at this stage.

Ultimately, photons > spectrum. Up to the point of light saturation, and then spectral changes can benefit through photomorphogenic manipulation < that's the hard part, knowing (learning) how different spectra interact with each other.

 

[Prawn Connery]

Something to consider with reptile lamps is even a high output 14% UVB lamp (Arcadia) actually produces more than twice as much UVA than UVB @ 30%.

That's correct, but in terms of the amount of energy those photons carry, and their UVR8 absorption, it's not as one-sided. However, UVA/UVB are really just arbitrary terms for the most part, as you're not going to see a difference between 320nm (UVB) and 321nm (UVA), so it's all a matter of context. (Some definitions use 310nm or 315nm as the cut-off point for UVB – goes to show how arbitrary it is.)

Reptisun 10.0 (10% UVB, 30% UVA)

 

[Rocket Soul]

Something to consider with reptile lamps is even a high output 14% UVB lamp (Arcadia) actually produces more than twice as much UVA than UVB @ 30%.

I find more uva than uvb desirable, your mimicking nature and ive heard much about uva facilitating for the uvb or repairing it.

 

[Rocket Soul]

Be careful with that. While sunlight peaks around 2000 umol/j, it is only a peak around mid-day. DLI, as you know, is the real metric. Plants are only exposed to such high light levels for an hour or two a day.


I keep saying to people the extra Far Red won't induce stretch, and that is due to the UVA at the other end. I'm glad you are now seeing this for yourself



If efficiency were not a concern, then that's what we'd be using, but the 660 bins we are getting are closer to 670nm, as you might be able to see from this report, so that's the best we can do at this stage.

Ultimately, photons > spectrum. Up to the point of light saturation, and then spectral changes can benefit through photomorphogenic manipulation < that's the hard part, knowing (learning) how different spectra interact with each other.



View attachment 18964108

I think the photons>spectrum is generally true, especially in the normal grow room. But still i dont think 1200ppfd of 450nm will out grow 1000ppfd of prawn board.
Efficiency> spectrum: i think this depends a bit. Efficiency and intensity are not exactly the same thing. How much efficiency and what spectrum? Also while efficiency plays a major role in intensity i think that as a grower its better to think of your watts as the main driver in intensity. You can allways just use more watts for a board to increase intensity but you cant change the spectrum really by more or less watts. But i don't wanna sound like im bashing on your boards infact i think its probably as close as you can get to where my mind is for all in one board. Proper supplementation of reds and near uv means you have to balance the 2 sides; if i understand correct you put 6 monos in series in the string rather than just one for most fixtures; this allows you to supplement in the blue side AND keep a good red/blue balance.

What im getting at is with 680 there would be a point where efficiency drop and spectrum benefits would be getting closer and closer.

The new setup with 680 is on an older fixture we jazzed up, we dont really have funds to do any full replacements for a while, at least until we start getting paid on time by our guy. So in order to jazz up our 2700k 90cri boards we made a single mono string to supplement. 4x400, 2x 385, 2x 365, 8x660, 4x 680, 2x730 spread out so the second channel pretty much targets chloro A blue and reds. My grow buddy seemed impressed, more than with the trays with 660 added but only half way thru the first grow so nothing definite to report yet.

 

[jackspratt61]

My calmag uses calcium nitrate and magnesium nitrate. 3:3:1 N:Ca:Mg. I think GH calmag uses calcium carbonate and epsom salts, as do others. I don't use them.

I'd be more concerned about them using calcium chloride

 

[Ca++]

Have you tried calcium nitrate and mgs instead of calmag?

No, but not for lack of trying. It's like trying to buy a controlled substance over here. Just this month I asked in a hydro shop I rarely visit, and they were like rabbits caught in the headlights. I swear I saw one think about the panic button.

It vanished a few years ago, at a time the police were talking to shops about the then upcoming dilution of h2o2 and Nitric acid. All talk revolving around bomb making. Most supply chains just decided to pull everything even remotely related.

Ammonium nitrate now has manufacturer ID indicators in it, that can be read miles away from an explosion. It's a controlled substance in the EU. All the traditional saltpeter stuff has gone. I'm not sure where calnit fits in with this, but I have just one eBay seller available to me, and that just seems like a bad idea.

The calmag I use is pretty much the numbers I would get from calnit and epsom. Which makes it particularly painful. 20p lost in every bucket.

I will keep looking, as it's really quite perfect

 

[weedemart]

I'd be more concerned about them using calcium chloride

Yup. Most calmag product use either calcium carbonate or calcium chloride.both terrible source of calcium
One of the reason why calmag products are just a waste of money.

If u lack calcium or magnesium take jackspratt advice; go with calcium nitrate or magnesium sulfate. its available as fertilizer everywhere on the internet and its cheap

but most of time you have plenty of mg and calcium.

 

[jackspratt61]

Yup. Most calmag product use either calcium carbonate or calcium chloride.both terrible source of calcium
One of the reason why calmag products are just a waste of money.

If u lack calcium or magnesium take jackspratt advice; go with calcium nitrate or magnesium sulfate. its available as fertilizer everywhere on the internet and its cheap

but most of time you have plenty of mg and calcium.

carbonates are good

Yup. Most calmag product use either calcium carbonate or calcium chloride.both terrible source of calcium
One of the reason why calmag products are just a waste of money.

If u lack calcium or magnesium take jackspratt advice; go with calcium nitrate or magnesium sulfate. its available as fertilizer everywhere on the internet and its cheap

but most of time you have plenty of mg and calcium.

Carbonates are good when balanced properly against bicarbonates