Best K (Kelvin) light value for positive (landrace) sativa effects?

[f-e]

For some years, people puzzled over why polytunnel plants were stronger than greenhouse grown. Eventually the right heads came together, and glasses greater ability to block UVB was realised to be behind the phenomena many had noticed from growing and smoking, but been unable to explain.

UV is simply damaging. The shorter the wave, the more damaging it gets. B might be 100 times more damaging than A, depending where in the A&B spectrum's you make the comparison.

UVA can be made with LEDs but UVB is a struggle. 0.02w might cost $50 and we want 1w a meter. $2500 per meter. UVA isn't so expensive, but B can be made fairly cheaply with fluorescent lamps, making the production of A using LEDs look equally as outrageous.

This leaves our UV production best done with flo's in the B band. Reptile bulbs can cover a meter for that $50 and $25 isn't unreasonable if you shop around.

Simply the act of causing damage triggers a protection response. This builds up a resilience within the plant though over time. So our first reaction is keep adding more UV. Recent tests have shown that pulsing the UV could trigger a good response without building up such a tolerance. Using a 7 day timer, our option would be 3 days a week. This was done with UVB over basil and saw 25% more flavour. A different crop, but not just different plants but also people seem to have a similarly adverse reaction, so it's not a huge leap, and one Bruce felt he should share.

The UVA LED's are in fittings because we keep asking for them. They're are just a waste of space that could of been occupied by a useful LED. Even for making fish look nice, UV LED lights are not really marketed. You find LED fittings with flo's hidden in the middle when you look.

One day we will have reasonable UVA LED's and will will know when the roboscan at the nightclub gets really funky.

 

[RenaissanceBrah]

For some years, people puzzled over why polytunnel plants were stronger than greenhouse grown. Eventually the right heads came together, and glasses greater ability to block UVB was realised to be behind the phenomena many had noticed from growing and smoking, but been unable to explain.

UV is simply damaging. The shorter the wave, the more damaging it gets. B might be 100 times more damaging than A, depending where in the A&B spectrum's you make the comparison.

UVA can be made with LEDs but UVB is a struggle. 0.02w might cost $50 and we want 1w a meter. $2500 per meter. UVA isn't so expensive, but B can be made fairly cheaply with fluorescent lamps, making the production of A using LEDs look equally as outrageous.

This leaves our UV production best done with flo's in the B band. Reptile bulbs can cover a meter for that $50 and $25 isn't unreasonable if you shop around.

Simply the act of causing damage triggers a protection response. This builds up a resilience within the plant though over time. So our first reaction is keep adding more UV. Recent tests have shown that pulsing the UV could trigger a good response without building up such a tolerance. Using a 7 day timer, our option would be 3 days a week. This was done with UVB over basil and saw 25% more flavour. A different crop, but not just different plants but also people seem to have a similarly adverse reaction, so it's not a huge leap, and one Bruce felt he should share.

The UVA LED's are in fittings because we keep asking for them. They're are just a waste of space that could of been occupied by a useful LED. Even for making fish look nice, UV LED lights are not really marketed. You find LED fittings with flo's hidden in the middle when you look.

One day we will have reasonable UVA LED's and will will know when the roboscan at the nightclub gets really funky.

Thanks f-e for your response. Would you say that just the potency went up with the addition of UVB? Or also the overall effect was more positive?

Also, so for example like the [LM301H 3500K+CREE XP-E2(660nm+730nm)+LG UV] light, would you say the extra LG UV is a waste of space, and better to get another light without the UV?

 

[RenaissanceBrah]

Hey, I've read the same thing and rev is completely right about the 530-640 orange to bright red abundance part which is absolutely what we see with hps. This is about deep red and far red though which weren't as readily available until just around 2015-2016 in horticultural led form and I have been glad to have them present

Equally his point about the blues in tube lights is totally valid - the Samsung LEDs, no matter what Kelvin you pick, all peak around 450nm or so, which leaves the cyan above it and the deeper blue/violet lacking.

The only broadband white 3030 size LEDs that really cover that region are the Seoul semiconductor 'sunlike' range (6500k is based on a 415nm pump) and Nichia 'optisolis' (5000k has a 420nm pump).



As mentioned, it's cheaper generally to not stress about getting a white led that covers all as the blue peak in Samsung lm301b/h is certainly useful but the broader bandwidth of blue rev alludes has valid uses.

405nm, 420nm and 440nm mono supplementals are readily available here in Europe, usually for the aquarium markets. They tend to be Epileds and in 1w/3w/10w format.

Uva below that (365/385/395nm) has been documented to be useful but 400-440 supplementation just as helpful but much easier to reproduce and less harmful to eyesight.

​​​​​​I can see the temptation towards 5000k of course but you do lose out on some useful reds. As we've discussed, it's nothing like daylight.

Thanks Bleep for that, I read through a few times and really appreciate the help on this.

In terms of effect for a equatorial sativa (ignoring yield and bag appeal and taste and all that, focusing purely on effect) how big of a difference do you think going with higher K and supplemental lighting (like the Seoul semiconductor sunlike range, Nichia, etc)... how much would it differ in effect from running the Kingbrite you mentioned [LM301H 3500K+CREE XP-E2(660nm+730nm)+LG UV], in your opinion?

 

[f-e]

It's not just potency that increases, no. It's the all round effect. Smell, taste, oil content, maybe not potency if measured simply as THC levels. It's lots of other compounds people are saying and I can back that up doing the same plants indoor and outdoor on many occasions. There is a lot more going on when plants are done outside.

I wouldn't get the UV in your lights, no way. The 730nm is also very questionable.

I have 20 seonds to get out the door...

 

[bleepboop]

It's okay f-e, I get it. Plenty of people out there smashing lm301 in 3000/3500k even without 660. I just don't want UVB around me, my eyes are a mess enough as it is. I used to run UVB reptile cfls alongside metal halides, gavita hps, various cob led floodlights, and early Samsung lm561c quantum boards.
cannabinoid production is certainly boosted but I have very little interest in ultra high thc levels. It could become uncomfortable sometimes and felt a little unnatural.

The last 18-24 months there's been enough side by sides and test grows with just boosting 390-440nm and still getting good flavours. I'm happy to see modest UVA and near UV use as an acceptable compromise to UVB cfls.

730nm - it's not always helpful, can certainly cause stretch as it promotes cell division a from shade avoidance. Nothing unmanageable for me though. I tend to leave it on through the whole daylight period now.

Re: RenaissanceBrah The Nichia/SSC doesn't really fit your budget, you'd need a fair few strips/panels to make up 480w which don't have North America distribution. You'd be better off getting whichever kingbrite panels you like. The xpg3 is a very efficient deep red diode indeed and it might be nice to have it for future proofing. There's things on places like rapidled if you want to get yourself extra supplement. They just cost more over there as I'm sure you're well aware.
here's a spectrum of the current swag booster board on there.
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Ultimately you have tried to amalgamate the best plan you can for this, it's a fun rabbit hole to go down for those of us who enjoy it or already have a background in LEDs for other fields. I definitely don't pretend to know all the answers but try and make as informed a decision as I am able.
I also am learning (to enjoy) the challenge of indoor sativas (TRSC Ukhrul 20wks)
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​​​​
​​​​​​Here's a lil grey oyster mushroom that popped up under the canopy

 

[f-e]

I'm a little concerned that 730 might actually be counter productive. I use it if I'm not getting the stretch I like, but stretch is vegetative growth, and comes before budding in the importance of things for a cannabis plant. Delays in flower formation have been seen, as the plant was more concerned with getting above it's neighbours than flowering in a less suitable location.

I was onboard when I saw the graphs of greater veg weight than the sum of 660&730 would suggest. It seems that's just in leafy greens looking for light though. So while I have the ability to extend the spectrum from where the 301s leave off, right out past 800nm, I use it very rarely. Just to promote stretch, which I'm learning is better done with raised P levels.

I might try the UVB again, which will be a 3rd go. I have never had a meaningful result from it though. Outdoor I have found even cloudy years develop more flavours than indoors (which of course means low UV years) so I'm not surprised to hear near-UV (whuuurt) having good effect. It's a lot of power though, when UVB is so much more effective. Or is that.. ineffective? I have been to mountainous levels but this pulsing idea is new. There are times of day I rarely visit and the need to turn off a batch of lighting when I do already. Movement sensor? I'm not bad with such controls (he says, looking at the pile of crap on his bench to have two soil moisture probes to bring on a pump from low level to high level, which in reality will end up in the runoff. Though the digital displays will look great)

 

[RenaissanceBrah]

Ultimately you have tried to amalgamate the best plan you can for this, it's a fun rabbit hole to go down for those of us who enjoy it or already have a background in LEDs for other fields. I definitely don't pretend to know all the answers but try and make as informed a decision as I am able.
I also am learning (to enjoy) the challenge of indoor sativas (TRSC Ukhrul 20wks)
​​​​​​ filedata/fetch?id=17805981&d=1616013643
​​​​
​​​​​​Here's a lil grey oyster mushroom that popped up under the canopy
filedata/fetch?id=17805980&d=1616013462

Looking good! That is a very interesting structure on the sativa bud. And I recently saw a similar oyster mushroom in this interesting video.

I'll most likely get that 3500K Kingbrite you mentioned, and I'm thinking of also getting one of their higher end 4000K light. Or think I should just run two of those 3500K's? (For strictly growing equatorial landrace sativas)

 

[f-e]

This topic of improving the gear has mostly revolved around UV and Violet itself. The blue to red ratio is what we will likely see change with a different white balance from the same series of LED's. Cooler light moving some power from red too blue. Blue hasn't actually been shown to have the desired result. It's been shown that cooler lamps lower yield.

There is a case for cooler light users kidding themselves it's better. I mean... I know mines the best in the world, right? But then how is everybody else saying theirs is. Wishful thinking is a powerful thing. Science seems to be leaving blue alone though in this arena where lab results are coming in.

Personally, right or wrong, I would stick with the warm whites and add additional spectrum to find additional results. Not just ratio out what I have differently. Some UV if it's from flo's. Violet could be LED's. I have blue through to red, and know about the far red and beyond as it's well researched. It's that violet and beyond I don't have and is being proven to do something quantifiable.

Nod to bleepboop there, as I have seen no work on violet, but obviously it's not well represented by grow lights.

 

[RenaissanceBrah]

This topic of improving the gear has mostly revolved around UV and Violet itself. The blue to red ratio is what we will likely see change with a different white balance from the same series of LED's. Cooler light moving some power from red too blue. Blue hasn't actually been shown to have the desired result. It's been shown that cooler lamps lower yield.

There is a case for cooler light users kidding themselves it's better. I mean... I know mines the best in the world, right? But then how is everybody else saying theirs is. Wishful thinking is a powerful thing. Science seems to be leaving blue alone though in this arena where lab results are coming in.

Personally, right or wrong, I would stick with the warm whites and add additional spectrum to find additional results. Not just ratio out what I have differently. Some UV if it's from flo's. Violet could be LED's. I have blue through to red, and know about the far red and beyond as it's well researched. It's that violet and beyond I don't have and is being proven to do something quantifiable.

Nod to bleepboop there, as I have seen no work on violet, but obviously it's not well represented by grow lights.

Thanks f-e - I know lower K lights (3000-4000) will have higher yields as they are better for flower, my main concern though was achieving best positive effect with an LED grow light, and I was going off of anecdotal evidence that higher K (4200K+, based on what Rev said) is required to unlock genetic potential and more positive effects.

Though realistically... if I grow under that Kingbrite 3500K light, I probably wouldn't see that much difference right? For my budget I think the two 240W Kingbrites would be best for now, perhaps I can add supplemental lighting in the future. For now not sure if I should get two 3500K lights, two 4000K, or one of each. Would you have any opinion on which of those Kingbrights to get, between the 3500K and 4000K? (for growing landrace sativas for positive effect, ignoring potency and yield).

 

[chilliwilli]

f-e. Have u tried the 730nm as an end of day threatment? Or just supplemental lighting?

 

[f-e]

Thanks f-e - I know lower K lights (3000-4000) will have higher yields as they are better for flower, my main concern though was achieving best positive effect with an LED grow light, and I was going off of anecdotal evidence that higher K (4200K+, based on what Rev said) is required to unlock genetic potential and more positive effects.

Though realistically... if I grow under that Kingbrite 3500K light, I probably wouldn't see that much difference right? For my budget I think the two 240W Kingbrites would be best for now, perhaps I can add supplemental lighting in the future. For now not sure if I should get two 3500K lights, two 4000K, or one of each. Would you have any opinion on which of those Kingbrights to get, between the 3500K and 4000K? (for growing landrace sativas for positive effect, ignoring potency and yield).

You could go through the microgrow post on cfl/led comparisons. A few growers there took advantage of the ease in which warm and cool lamps could be swapped about. It's not ideal info as we can't say the spectrum of these lamps or see if users were switching brands. However there has never been a mass shift in attitude towards swapping out some red for more blue. Go back 10 years and we saw MH being swapped for HPS and the effect was real and to our eyes because it was more blue. It was a lot more Violet/UV to though. Which the more involved growers knew, but full on lighting geeks are just one voice in a large crowd. The idea of blue stuck.

There is little too no gain in violet or UV from buying cooler lamps. I buy 3000K and warm them up with 660s. A happy plant won't just yield more, it does more. If later you wish to bombard them with UV to make them unhappy, it's really very cheap. $20 reptite lamps in $10 white painted hoods.

I must look at the links provided for coloured strips such as violet, but with the pro growers chasing after UV I feel it's finally coming of age. My first UV lamp was over 25 years ago, so it's quite established now. I used UV-C. My face swelled up till I couldn't open my eyes. The plant died. It was a result...


chilliwilli No just supplemental for morphology. I thought about hitting my DLI in 10 hours, then sending them to sleep faster, to get them up earlier. Other than that I don't see a gain. I'm not sure we can get far from a 24 hours day though.

 

[bleepboop]

Thanks for taking the time f-e, I've been run off my feet for a bit and not felt composed enough to do a reply.

Re: violet, led teknik in Melbourne developed a 3 die chip (I think in 3030 format) with 1x405nm & 2x 420nm which has made it into a grow lights australia quantum board and will soon be released in the "buddies" strings. Also I think cutter electronics has put it/a copy of it in a 3030 strip with 7 of them mixed into a white strip.

Mouser and digikey have some 1-3w starboard chips in the various UV formats.