Cabrone
Well-Known Member
Anytime, you share good info quite often
More THC testing – UVA vs UVB vs near-UV
- Thread starter Grow Lights Australia
- Start date
race winslow
Well-Known Member
Hi, Late to the party on this. Just wondering if you ended up using the Solacures? If so, were you happy with the results?I've been following your work with great interest and commend you on all your efforts. I have my main lighting set up satisfactorily, but wondered if you have considered producing a UV only lamp (like HLG's offering). I have 100 sq ft of canopy so theirs is a bit pricey! I have an unopened box of 8 Solacures I'll install in a few weeks (in the middle of harvest now) so I'll see what they do.
Here's an interesting read from a lighting company I hadn't heard of, discussing the uvr8 pathway and the synergy of uva and uvb.
The MetaRail™ UVB+A Lighting Instrument — AgricUltra™ Advancements
The MetaRail is designed to deliver the industry’s most advanced UV spectrum and power density in the optimal ratio of UVA:UVB wavelengths to optimize plant attributes—such as improving flavour in strawberries and increasing THC levels in Cannabis plants.www.agricultra.com
Thanks
nDanger
Well-Known Member
Hey Race! Haven't really formed an opinion yet. I thought the tricome density looked greater with them. They certainly didn't hurt.
There's something lacking in my setup. First I think my ChilLED lights are just too damn bright, so I'm doing this next crop with them as high as they look in my profile pic. Been getting out of control foxtailing, not burning. Second, I've had 5 crops using different seeds from different breeders and they all come in at 15%! With and without the UV, so I can't tell if the UV helped any or not! My wife didn't like the "danger" aspect of them so we didn't run them for most of a crop, until we had a spider mite invasion. Flipped them on for an hour twice a day and killed 80% in 2 days, the rest in a few more.
So there's that helpful use for them. Sorry I can't add the recommendation I'd hoped for.
race winslow
Well-Known Member
Hey, thanks for the update. I'm going to be harvesting in the next couple of days. I'm hoping to have lab results in about 3-4 weeks. Regardless, using UV really upped the terpene and resin production. I'm going to do another run with them once the summer passes.
Also, sorry to hear about spider mites....at least the UV helped to eliminate them. It also helps to keep bud rot away.
I'll be posting updates as things progress.
I'm going to start the harvest on this latter today
Also, sorry to hear about spider mites....at least the UV helped to eliminate them. It also helps to keep bud rot away.
I'll be posting updates as things progress.
I'm going to start the harvest on this latter today
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MidnightSun72
Well-Known Member
I wonder does UVA have a similar effect to UvB in terms of the bug and mold killing effect?
nDanger
Well-Known Member
Certainly won't be the SAME effect. Spend 30 min under FRESH Solacure lamps and you'll feel the mild sunburn for a couple of days. I'm sure that will toast the little buggers.
race winslow
Well-Known Member
There's a lot discussion. However, 100% proof is elusive.
Here's an older link that I found that doesn't seem to be product sponsored.
UVA UVB Lighting To Kill Powdery Mildew And Mold
UVA UVB Lighting To Kill Powdery Mildew And Mold I have been doing some research into the use of UVA UVB lighting to either control, kill...
medicalmarijuanagrowing.blogspot.com
Overall, I'm going to continue with it. It has been working for me.
ttystikk
Well-Known Member
UVA is the weakest of the UV spectrum. Its effects are least powerful per Watt. That doesn't mean it's useless. Skin covering and eye protection is highly recommended when working in such light.
UVB is much stronger per Watt and should be used with care; less intensity and be sure to harden plants to it gently. It is more effective against PM, although I'm not sure about bugs. It's important to shut it off when working in the space, or at least cover your skin and wear protective eyewear. It will definitely inhibit PM and probably other bugs as well to some extent.
UVC is again far stronger than UVB and should not be used anywhere it might contact plants, skin or eyes. It is used as an industrial sterilant and should be treated with respect.
Hope that helps.
Grow Lights Australia
Well-Known Member
I asked @Prawn Connery to answer this and his short answer was "No". He said he still had to watch out for mites and aphids under UVA. I guess that makes sense as the sun doesn't seem to kill off mites and aphids outdoors but maybe that's because they hide under the leaves. Perhaps it also depends on the UV wavelength. As we all know, UVA from about 365nm onwards attracts most insects and in some greenhouses they try to block UVA light from entering so as not to attract insects that might attack crops. I'd suggest UVA is not very effective at preventing insects.
There is another grower on these boards who works with us and he uses UVB reptile bulbs but still has problems with botrytis at times, so I'm not sure how effective UVB is at killing or controlling mould in lower doses.
MidnightSun72
Well-Known Member
Thx for this post. Was more or less what I was trying to confirm.
Let me add to the confusion.
I found this study a while back that suggested blue and white LEDs were enough to disrupt the mites cells or something and kill them.
And I actually have a cheap blurple (also has included Uv diodes ) I switched to just the blue spectrum that I shon on the bottom of the leaves of a plant. I found it did not kill any mites.
Also I am sure UVB doesn't entirely kill mites either. I have a feeling it's more a function of the energy delivered to the plants and the bugs. If they receive high enough energy either through short duration UVB or high duration of a weaker light (in terms of wave energy).
Grow Lights Australia
Well-Known Member
Thanks for the study but I can't help thinking that if white light is so effective against mites then why are all LED growers prone to them? Almost every LED grower I know has dealt with mites at some stage or another, LOL!
Cloning is a good example as many growers use a high CCT light around 5000-6500K to propagate under 24 hours of light and yet clones still carry mites. 6500K has a lot of blue light in it.
race winslow
Well-Known Member
Hey, thanks for the update. I'm going to be harvesting in the next couple of days. I'm hoping to have lab results in about 3-4 weeks. Regardless, using UV really upped the terpene and resin production. I'm going to do another run with them once the summer passes.
Also, sorry to hear about spider mites....at least the UV helped to eliminate them. It also helps to keep bud rot away.
I'll be posting updates as things progress.
I'm going to start the harvest on this latter todayView attachment 4917692
Okay, so the results are in from this experiment.
Conclusion - At least for me, the results were mixed at best. The UV did not seem to make an appreciable difference in THC production and seemed to provide a slight enhancement to taste and smell. The overall yield did not seem to be impacted either.
The two strains I grew were Bruce Banner and Fruity Chronic Juice. According to various breeders the THC potential is as follows:
Bruce Banner 18 to 28%
Fruity Chronic 15 t0 22%
Test results were:
The results for the Bruce Banner were surprising. I've smoked both of these. The Bruce Banner definitely seems to make me feel higher than the Fruity Chronic even though there seems to be much more THC in the Fruity CJ.
It was a worthwhile experiment for my own curiosity. I'm going to give it another try with different strains. If those results are similar I will discontinue use.
I would say it's worth experimenting with UV if you're interested. Your results may differ. This was by no means a scientific experiment.
Grow Lights Australia
Well-Known Member
Hi mate, the link to the test results is broken for me so I can't see them.
You are using UVB fluoro lights aren't you? If the test results were not what you expected then this may be a reflection of what we've been seeing with UVB. Namely that it increases cannabinoid production in plants but it also breaks down those same cannabinoids at the same time. We have seen this in a few grows but it might also be a result of running UVB for too long during each 12/12 cycle. Or perhaps running it too strong. If I remember correctly you have a fair bit of UVB going on in your grow.
Have you ever tried using just UVA or near-UV around 400nm?
You are using UVB fluoro lights aren't you? If the test results were not what you expected then this may be a reflection of what we've been seeing with UVB. Namely that it increases cannabinoid production in plants but it also breaks down those same cannabinoids at the same time. We have seen this in a few grows but it might also be a result of running UVB for too long during each 12/12 cycle. Or perhaps running it too strong. If I remember correctly you have a fair bit of UVB going on in your grow.
Have you ever tried using just UVA or near-UV around 400nm?
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race winslow
Well-Known Member
Yes, using the fluoro's. No, I haven't tried just UVA. I do think that I can run them for less time per day and delay the introduction to the plants. At this point I do need to change my approach. I guess the million dollar question is - Is UV use for indoor growing that much of a value add? I will have a different approach next time and I appreciate your input. I'm not trying to invent the wheel here, just a little sort of informed/haphazard experimentation.
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Grow Lights Australia
Well-Known Member
Well 20% is still not bad. I'm wondering if the plants were in different positions relative to the UV light? I'm guessing you haven't grown these before without UVB.
race winslow
Well-Known Member
I would say that the plants got fairly equal amounts of UV. The positioning was limited as the grow was done in RDWC and the plants were in a fixed location. Both plants were grown from seeds so I don't have clones of them and had not grown them previously. This was more about determining whether added UV would help to gain increases in THC relative to the breeder's estimates for each strain.
I've got a Wild Thai strain going under a smaller set-up with UV. One plant, one SolaCure bulb with less wattage. I'm going to delay the UV to approximately 4 weeks after onset of flowering and shorten the duration given per 12 hour cycle. However, there are other variables at play including the use of a less powerful grow light and it's being grown in soil verses hydro. So, it's not really a direct comparison to the previous grow. I'll be doing another hydro grow with UV in a couple of months. Currently it's too hot for hydro where I am located and I don't feel like investing in a chiller.
Speedtriplebbc
Well-Known Member
I remember reading 385nm and 285nm create a synergy like the Emerson effect for trichome production but can’t find it for a link? I have two of the miro grow T8 uvb lights I’ve hardly used as I read this after purchasing and before installing. I don’t think I’ll run them long looking at the results here, probably 30-60 minutes max. Especially as I accidentally left the timer on permanently for 20 hours and could see damage to the plants. I’m more inclined to just add a bit of 385nm at 1w per square foot. Here’s a pic I took of one of my builds with everything on including uvb and my initiator.
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Rocket Soul
Well-Known Member
I've heard stuff thrown around here on the forum in these terms, but not so specific. 3 parts of uva to 1 part uvb, as measured in radiant output.
I don't know about 385nm specifically. It's also hard to measure these things accurately as the research testing gets complicated. It may simply be that the manufacturer had 385 in his light so they claimed that, just speculating.
Generally speaking the uva response (stomata aperture amongst others) is concentrated around 365nm and the uvb response at around 280 (but as it is har to have 280 without lower uvc nm generally people use 285-290nm)
I would expect that stimulation and synergy between uva and uvb would reuse the same nanometers; nature is clever like that but again speculating.
I don't know about 385nm specifically. It's also hard to measure these things accurately as the research testing gets complicated. It may simply be that the manufacturer had 385 in his light so they claimed that, just speculating.
Generally speaking the uva response (stomata aperture amongst others) is concentrated around 365nm and the uvb response at around 280 (but as it is har to have 280 without lower uvc nm generally people use 285-290nm)
I would expect that stimulation and synergy between uva and uvb would reuse the same nanometers; nature is clever like that but again speculating.
Speedtriplebbc
Well-Known Member
To be fair, this kind of spectrum tuning is relatively new, I have one room that’s almost all highlight 420’s as they’re damn good and all the hard work has been don’t to make a great efficiency and spectrum for flowering cannabis. But I still play around in the other room and sometimes get surprised if I try something different with a new strain. A selection of plasma, cmh, boards and strips that I switch around like a mad scientist.