Randomblame
Well-Known Member
This is a paper about UVB, what it does and how it works.
Help regarding choosing solution for adding UVA/UVB LED's to a DIY COB LED grow light.
- Thread starter Planet Tomato
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Planet Tomato
Member
I can really agree with that sentiment, it is the same with the nutrient side of things in that I was told to stick to the base nutrients and not use any additive until I have learned more about the basics and in case problems arise they will be harder to diagnose if I am using a lot of products.
But I haven't been able to help my self, although I am growing organically I have used a couple of non-organic additives, for example I couldn't resist trying Dutch Master Saturator(the gold version, now they have a more concentrated version named "Commercial Edition Saturator"). Otherwise the sort of additives I have used have been(it became a full list of all product I have used):
- Full Bio Canna range, Bio Vega, Bio Rhizotonic, Bio Flores and Bio Boost, also Canna's Bio PH- which is mainly citric acid.
- Plant Magic, Old Timer Organic PK 4-8.
- Magne-Cal+(Plant Magic), though this is required if using the Bio Canna range using soft-water in order to harden the water.
- Nitrozyme(Growth Technology), used to encourage short internodal lengths and general growth enhancer.
- Carbon Overload(Fearless Gardener, Dare to Grow), weird name since it is simply Humic acid.
- Bio-Silicon(Plant Magic), which I am glad I added, it's a long story to tell why though.
- Flavinator(Fearless Gardener, Dare to Grow).
- Gold Saturator(Dutch Master).
- Great White(Plant Success).
I am on my first grow ever but it has gone pretty smoothly although I turned a hole layer of leafs 100% yellow trying out my LED grow light(which I made way too power full I think, if I up my game with experience and make sure the plant have all the nute's it could want then I may be able to utilize the full 300W of my COB grow light) combined with too little nutrients at that time, it seems like that really depleted the soil because now I have used more than 100% recommanded dose every watering for 5 waterings in a row and the PH of the run-off indicates they are still hungry and the colour of the growth tips point to that also.
I am not really aware of why I am making these choices but I will go ahead with the UVA LED's anyway, actually I'm pretty convinced that boredom is one of the factors and the second might be the fact that I have severe ADD plus high-functioning autism which combines into a situation in which I often can't get the things done that I want to do but I managed to put this grow together and it might be that I keep expanding the complexity of my grow simply for the pleasure of actually getting stuff done.
In any case I will build the system which will have a large range in terms of adjustable constant current output and then think about how to add the correct amount of UV.
Planet Tomato
Member
Yes that gave me a few important considerations but I have a couple of questions.
I have bought a cheap LX-1010B Lux-meter:
My grow light are using 2 * CXM-32-35-80-54-AC00-F2-3 and I run them in a way that estimated from the datasheet charts should be around 170W together(so 85W each), do any of you have any idea about what sort of value I can expect from using this Lux-meter to convert the lm into PAR or PPFD in terms of relevance to reality?
I understand that it would have to do with what conversion factor I am using but(and maybe I should open another thread about this), but I am just thinking "if I have the spectrum of the LUX-meter, and the spectrum of my light source, could I make some sort of fairly accurate(+-20% would be considered fairly accurate in this situation I think) estimation of the PAR/PPFD of my light?
I have read a couple of different threads on other forums where the OP modifies such a Lux-meter(LX-1010B) into a PAR meter but the crux for me is that even though replacing the light-sensitive diode inside the probe is easy you need 3 different light-filter sheets to filter out IR and modify the spectrum reaching the diode enough to make it compliant with the PAR definition and this 3 filter materials are not easy to acquire, I can't recall the company whom sells these sample books which contains these along with 10's or up towards 100 other filter materials and I need 1/10 or 1/20 out of 3 of those 100... and it used to be easily available a few years ago but for some reason they are now expensive and hard to come by. And I just can't pay so much money for those 3 little peaces that I need to filter the light into a PAR comparable spectrum.
BTW, I shouldn't need to filter the IR since my grow light doesn't feature any IR light.
It sounds as it is crucial to at least find a fair estimate of the PAR of my grow light, though I'm afraid that event though i think the info in the datasheet of my COB LED should be enough to calculate the PAR I simply lack the knowlagde of how to do it and I get confused when I try to research the subject.
If anyone knows of any info or resource that could be helpful in this matter I really like to know about it.
If I know the amount of lumen that my LED's are rated to output(around 17000) and the processing done to get a value in lumen, as well as the specific spectrum of the LED's and the definition of PAR, then I should be able to sort of reverse engineer the lumen calculation process in order to then be able to calculate further the PAR value. I have access to Matlab(student license) which might be handy for trying something like this.
Planet Tomato
Member
Sorry for the number of long posts but this one contains some actual relevant values.
I'm not sure how to put this together but I figured I'll post this while I think about it.
The following info and pictures concerns the Migro 100 grow light(which uses more or less the same LED as I use(CXM-32) but they only use 1 at 107W where I use 2 at 85W each, also note that the Migro 100 features a 90° Diffused Borosilicate glass lens and the pictures and values are based upon that, I have no idea about how that changes the output in terms of PPFD or PPF(µmols/sec)):
Flowering coverage: up to 60cm x 60cm (2ft x 2ft)
Vegging coverage: up to 90cm x 90cm (3ft x 3ft)
Power consumed: 107watts
Total PPF: 239 µmols/sec
Efficiency PPF/Watt: 2.2 µmols/watt
Is this info of value for me to work out the way to drive these UVA LED's?
The LED's are rated as the following when run at 500mA and 25°C(the actual LED's are Luminus SST-10-UV-A130):
LST1-01G01-UV01-00:
365nm, 130°, 3.6V, 875mW, 2.69uMol/s, 1.49uMol/J
LST1-01G01-UV02-00:
385nm, 130°, 3.4V, 1015mW, 3.24uMol/s, 1.91uMol/J
LST1-01G01-UV03-00:
395nm, 130°, 3.4V, 1015mW, 3.35uMol/s, 1.97uMol/J
LST1-01G01-UV04-00:
405nm, 130°, 3.4V, 930mW, 3.14uMol/s, 1.85uMol/J
And I will use 1 of each and I'll have the possibility to adjust the current between 0mA - 1050mA.
I will rebuild my grow light in order to separate my CXM-32's further apart from each other to create a more even light intensity, now they are mounted about 10cm apart and on the new heatsink I may double that distance, and in between those will be the UVA LED's.
I only have a 60cm * 60cm space.
I'm not sure how to put this together but I figured I'll post this while I think about it.
The following info and pictures concerns the Migro 100 grow light(which uses more or less the same LED as I use(CXM-32) but they only use 1 at 107W where I use 2 at 85W each, also note that the Migro 100 features a 90° Diffused Borosilicate glass lens and the pictures and values are based upon that, I have no idea about how that changes the output in terms of PPFD or PPF(µmols/sec)):
Flowering coverage: up to 60cm x 60cm (2ft x 2ft)
Vegging coverage: up to 90cm x 90cm (3ft x 3ft)
Power consumed: 107watts
Total PPF: 239 µmols/sec
Efficiency PPF/Watt: 2.2 µmols/watt
Is this info of value for me to work out the way to drive these UVA LED's?
The LED's are rated as the following when run at 500mA and 25°C(the actual LED's are Luminus SST-10-UV-A130):
LST1-01G01-UV01-00:
365nm, 130°, 3.6V, 875mW, 2.69uMol/s, 1.49uMol/J
LST1-01G01-UV02-00:
385nm, 130°, 3.4V, 1015mW, 3.24uMol/s, 1.91uMol/J
LST1-01G01-UV03-00:
395nm, 130°, 3.4V, 1015mW, 3.35uMol/s, 1.97uMol/J
LST1-01G01-UV04-00:
405nm, 130°, 3.4V, 930mW, 3.14uMol/s, 1.85uMol/J
And I will use 1 of each and I'll have the possibility to adjust the current between 0mA - 1050mA.
I will rebuild my grow light in order to separate my CXM-32's further apart from each other to create a more even light intensity, now they are mounted about 10cm apart and on the new heatsink I may double that distance, and in between those will be the UVA LED's.
I only have a 60cm * 60cm space.
SSR
Well-Known Member
@Planet Tomato
Its great to see your enthusiasm but here's a couple things
Its your first grow. Learn to dial in your grow and get consistent results, that can be challenging enough for some people in larger grow areas, yours is quite small so more susceptible to temp and humidity swings etc
As previously mentioned it doesn't take a lot to lose what you gain from UV, the plants need to be happy all the time and you need to know what youre looking for to catch things as early as you can
If you're struggling to work out your radiometric output i suggest you play with far red and not UV. You'll still experiment but won't hurt your plants plus you can have a bit of fun figuring things out along the way.
Search for greengenes and growmau5 on youtube, watch growmau5's beginner led series and go from there.
Not trying to put you off, just put you on the right track
Its great to see your enthusiasm but here's a couple things
Its your first grow. Learn to dial in your grow and get consistent results, that can be challenging enough for some people in larger grow areas, yours is quite small so more susceptible to temp and humidity swings etc
As previously mentioned it doesn't take a lot to lose what you gain from UV, the plants need to be happy all the time and you need to know what youre looking for to catch things as early as you can
If you're struggling to work out your radiometric output i suggest you play with far red and not UV. You'll still experiment but won't hurt your plants plus you can have a bit of fun figuring things out along the way.
Search for greengenes and growmau5 on youtube, watch growmau5's beginner led series and go from there.
Not trying to put you off, just put you on the right track
Airwalker16
Well-Known Member
Why are you so set on UVA? You're not going to add any UVB at all?
SSR
Well-Known Member
I have a similar condition as does a person i met on here.
Use it to your advantage, use it to dial things in as best as you can and when you have a few harvests under your belt and can say things for certain about your grow then look at adding extras, and..... Start with the opposite end of the spectrum and the par spectrum.
Heres a link to growmua5 videos i mentioned
Edited to add a link to his channel since the links for the vids automatically embed
https://m.youtube.com/channel/UCPSwmwj8ZLXObtBJmz-76rw
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Planet Tomato
Member
No not at all, if anything I appreciate your honest opinion(and I'm the kind of person who really do need to be told to slow down and be more patient sometimes) but my reasoning here is this:
In any case I will need 2 seperate drivers for the UVA and UVB lights and the UVA LED+driver choice I have made is very adjustable and can for sure provide me with the intensity setting that I in the end would require, together with my way of control i.e. RTC based microcontroller controlled relay, I can implement the system now but I don't have to decide how to actually use it and then in time when I feel I know what I am doing I can start to use it. Since I am able right now to afford the system, which can change in the future.
I was actually about to write and ask(mostly out of curiosity and to gain perspective) how do you tell if you get any gains from UV supplementation?
I don't know but from looking at the buds I have smoked and experiencing the potency of them I am hesitant to call a frosty buds to be a very potent bud simply due to the frosty appearance, AFAIK there aren't any affordable way to quantitatively test the THC content of buds which AFAIK requires the buds to be sent to a actual professional lab which features a price that no one like me can afford.
But if anyone feels like writing a little about how they judge the result and there reasoning I'd love to hear about it, do you use your smoking experience as the "measurement" of the UV's impact?
I really want UVA and UVB but 1 UVB LED cost as much as all 4 UVA LED's + the driver for them, so it's just that I want to get the UVA right away and then maybe as the UVB technology evolves add on UVB or wait a while until I can afford to invest in 1 or 2 UVB LED's + driver.
Plus the fact that they apparently doesn't last long(UVB LED's), a short lived UVB LED for 80 bucks is not something that makes me feel optimistic.
I have read that UVA indeed does suffice although UVB might be more effective, but that I read on a blog belonging to a company in the US who makes LED grow lights which contains UV LED's. So I am in doubt of the honesty of the info since I know that it is rampant within the young LED grow light industry targeting people like my to spread false information to promote there product(I am primarily thinking of the sort of LED grow light produced in China and sold on Amazon and ebay, and some of those adds are just filled to the brim with pure BS and misleading information, though I don't know about if that is the case to any degree with more serious producers such as the aforementioned US based producer which I can't recall the name of).
Maybe I am just suspicious or untrusting but I can imagine a motive for a company using UVA LED's in there grow light to provide subjective information lacking real data that UVA is enough for reaping the benefits of UV supplementation.
I suspect that the solution, the calculations I need to do to work this out is far simpler than I fear, I have read enough to know what the different quantities are but the problem for me is when there is a need to convert one quantity to another such as relating PAR to PPFD.
I do actually believe that I should be able to work this out, maybe I simply need more time to digest all this info and thoughts.
I might have written that before that I have high-functioning autism, which sometimes makes communicating on forums very troubling for me and some experiences on other forums have made me straight out afraid of posting on forums due to the aggressive and hostile attitudes I have received in the past, but this forum in particular have really made me feel much more confident and safe to post on forums. I really appreciate the friendliness and polite as well as honest treatment I have received here.
This thread and the replies have made me very happy for some reason, really have made my day today
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Planet Tomato
Member
Some error occurred when I was posting so 3 or 4 identical posts was made, they are since deleted but I have also edited the post a few times directly after posting, just FYI.
SSR
Well-Known Member
@Planet Tomato
I didnt realise this was your first grow when i replied initially.
Im not gonna give much more advice on this till you've a bit more experience, my reasons being:
You have a small grow space, if this was dedicated to experiments then fine but it's your actual grow space.
If you haven't dialed everything in, adding more complexity will likely lead to frustration, i dont want to be the guy that cost you a grow. (Just look at how many posts there are relating to plant health from beginners)
We all wanted to jump into the deep end of the pool but had to learn to swim first
If you've already got the diodes & drivers and you're absolutely insistent on adding UV then stick to UVa and keep it to 3-4% of your radiometric output.
Cheers
SSR
I didnt realise this was your first grow when i replied initially.
Im not gonna give much more advice on this till you've a bit more experience, my reasons being:
You have a small grow space, if this was dedicated to experiments then fine but it's your actual grow space.
If you haven't dialed everything in, adding more complexity will likely lead to frustration, i dont want to be the guy that cost you a grow. (Just look at how many posts there are relating to plant health from beginners)
We all wanted to jump into the deep end of the pool but had to learn to swim first
If you've already got the diodes & drivers and you're absolutely insistent on adding UV then stick to UVa and keep it to 3-4% of your radiometric output.
Cheers
SSR
Randomblame
Well-Known Member
On a summer day with clear sky ~1000PAR/w hits the earth and around 5% is UVA/B radiation. That's ~50w and only 2,5% of the light falls in the UVB range from 290-320nm. There is no UVB below 290nm because of the ozon layer and these wavelength are more dangerous anyway. A 275nm diode throws off a fair bit of UVC already.
In the paper I've posted above they used 6,7 and 13,4kJ/m² as the daily dose of UVB radiation and they found out the thc content increased almost linear with increased UVB radiation. The daily UV dose is expressed in Joule per m2 or mJ/cm². You need to convert it in μWs/cm². Simple formula is 1J/m² = 100μWs/cm² = 0,1mJ/cm².
Let's take the example above and figure out how strong a light source have to be to get 13,4kJ/m² each day.
13,4kJ/m² would be 13.400.000μWs/cm² or 13.400mJ/cm². We need 13.400.000μWs and we have 12h to distribute it so 13.400.000 : 12h : 60min : 60sec means ~310μW/cm² UVB every second. 310μW would be a 12.5 on the UV index scale btw.(μW/cm² divided be factor 25= UV index)
With PureUV bulbs you get ~300μW/cm² at 16-18" from sensor. A reptile bulb with 12% UVB is only 100-120μW/cm² at 16" but when you measure with sensor directly on the bulb it's +2500μW/cm²! The Arcadia reptile bulbs mimic the sunlight pretty well and all the numbers are available from several tests. Not so with these UV diodes. You only have the numbers from datasheet but you don't know how much it is left between 1 and 2' away from the fixture.
Without a UVB sensor it's almost impossible to figure out how much diodes you need and how hard they have to run to get the desired 300μW/s/cm² you need. And I dont believe you need 20 times more UVA than B like in the sun. Good desert reptile bulbs like the T5HO Arcadias have 2,5-3x as much UVA than B(12% vs. 30%). UVB gets mostly absorbed by the thc acids but UVA will hit the leaf tissues and is absorbed by cryptochromes and flavonoids. Too much UVA can damage the plant and because these pigments are more for signaling than photosynthesis you need less of these wavelength. It's like with blue light. Its the highest part in natural sun light but you only need ~10% blue light when growing indoors.
In the paper I've posted above they used 6,7 and 13,4kJ/m² as the daily dose of UVB radiation and they found out the thc content increased almost linear with increased UVB radiation. The daily UV dose is expressed in Joule per m2 or mJ/cm². You need to convert it in μWs/cm². Simple formula is 1J/m² = 100μWs/cm² = 0,1mJ/cm².
Let's take the example above and figure out how strong a light source have to be to get 13,4kJ/m² each day.
13,4kJ/m² would be 13.400.000μWs/cm² or 13.400mJ/cm². We need 13.400.000μWs and we have 12h to distribute it so 13.400.000 : 12h : 60min : 60sec means ~310μW/cm² UVB every second. 310μW would be a 12.5 on the UV index scale btw.(μW/cm² divided be factor 25= UV index)
With PureUV bulbs you get ~300μW/cm² at 16-18" from sensor. A reptile bulb with 12% UVB is only 100-120μW/cm² at 16" but when you measure with sensor directly on the bulb it's +2500μW/cm²! The Arcadia reptile bulbs mimic the sunlight pretty well and all the numbers are available from several tests. Not so with these UV diodes. You only have the numbers from datasheet but you don't know how much it is left between 1 and 2' away from the fixture.
Without a UVB sensor it's almost impossible to figure out how much diodes you need and how hard they have to run to get the desired 300μW/s/cm² you need. And I dont believe you need 20 times more UVA than B like in the sun. Good desert reptile bulbs like the T5HO Arcadias have 2,5-3x as much UVA than B(12% vs. 30%). UVB gets mostly absorbed by the thc acids but UVA will hit the leaf tissues and is absorbed by cryptochromes and flavonoids. Too much UVA can damage the plant and because these pigments are more for signaling than photosynthesis you need less of these wavelength. It's like with blue light. Its the highest part in natural sun light but you only need ~10% blue light when growing indoors.
SSR
Well-Known Member
@Planet Tomato, skip to 1 hour, 9 minutes and listen to what they say. Hopefully you'll get what i meant by problems
sato108
Well-Known Member
If you're still looking:
https://www.stevesleds.com/Ultra-Violet-365nm--UVA-3W-LED_p_299.html. $10.95
https://www.rapidled.com/semileds-ultra-violet-uva-led-390-400nm/ $5
https://www.stevesleds.com/Ultra-Violet-365nm--UVA-3W-LED_p_299.html. $10.95
https://www.rapidled.com/semileds-ultra-violet-uva-led-390-400nm/ $5
nfhiggs
Well-Known Member
To be quite honest - you really can't. Even testing is not going to tell you what it would have been without it. The only way to determine its effect is to do many, many double blind grows with and without the UV and perform a rigorous statistical analysis of the results - thats REAL science, not the silly "side by side" nonsense you see so often here and elsewhere.
Kushash
Well-Known Member
I'd like to help you with your grow.
Not with your lights, that's for the other guys.
I have a lot of experience growing in soil and my concern is that you are using to many types of nutrients.
With a quality soil and quality water you can get pretty far along with just water.
It's a learning process.
How far along is your grow?
What soil are you using?
Do you have a TDS meter? If not you should get one.
https://www.growweedeasy.com/ppm
My guess is that your yellowing is from something other than your light.
Pictures would help but it's fine if you prefer not to show them.
These forums can be very mean at times but you have a nice thread with good people on it.
I can probably help get your next grow off to a better start just from your write up.
These forums can be very mean at times but you have a nice thread with good people on it.
I can probably help get your next grow off to a better start just from your write up.
SSR
Well-Known Member
Too true but for those of us living in red states/countries we do the best we can. Backyard science can perform, just not aswell as labs can.
nfhiggs
Well-Known Member
No, not really. Its no better than anecdotal evidence which is scientifically useless. The reason "side by sides" are not valid and useful in any meaningful way is that there is normal variation among plants anyway, even clones in virtually identical conditions will exhibit some variability in both yield and potency. Add the fact that the grower KNOWS which plant is getting the UV and which one isn't - that potentially introduces confirmation bias. When the researcher knows which plant is getting the treatment, he may consciously or unconsciously treat that plant more favorably, thus "confirming" what he already believes.
The only way to factor these things out is with many dozens of grows using blind techniques and statistical analysis of the results. To my knowledge, no such studies have been done.
SSR
Well-Known Member
Given what you've said about plant variability the same would apply to labs/proffessionals. I know they run hundreds of plants at a time for testing to try rule that out though.
You are right about the plants possibly getting more favourable attention though.
With the length of time some people have had legalisation i honestly expected more published studies in recent years, shame people seem to be more interested in the money
You are right about the plants possibly getting more favourable attention though.
With the length of time some people have had legalisation i honestly expected more published studies in recent years, shame people seem to be more interested in the money
nfhiggs
Well-Known Member
Thats the key right there - running dozens and dozens of plants allows you to get statistical mean values and effectively normalize the inherent variations - then you can actually see if UV is making a difference or not. You have to be able to look at averages of very large groups, and side by sides does not get you there.
Yeah, me too. but we're getting there I think, if we can get Feds to remove it as a schedule 1 I think we will see much more published research.