Adding UV To A Grow

[Lovie]

This is the article I was referencing.

Indoor grown cannabis yield increased proportionally with light intensity, but ultraviolet radiation did not affect yield or cannabinoid content - PMC

Cannabis (Cannabis sativa) flourishes under high light intensities (LI); making it an expensive commodity to grow in controlled environments, despite its high market value. It is commonly believed that cannabis secondary metabolite levels may be ...

pmc.ncbi.nlm.nih.gov

I have not read it in its entirety because I lack the attention span to do so but from what I skimmed it pretty much says the UV lighting had little effect on the THC and CBD content in the leaf tissue but there was a very noticeable difference in the amount of trichomes from the control plant with no UV light vs the one with UVA and one with UVA and UVB.

 

[Delps8]

This is the article I was referencing.

Indoor grown cannabis yield increased proportionally with light intensity, but ultraviolet radiation did not affect yield or cannabinoid content - PMC

Cannabis (Cannabis sativa) flourishes under high light intensities (LI); making it an expensive commodity to grow in controlled environments, despite its high market value. It is commonly believed that cannabis secondary metabolite levels may be ...

pmc.ncbi.nlm.nih.gov

I have not read it in its entirety because I lack the attention span to do so but from what I skimmed it pretty much says the UV lighting had little effect on the THC and CBD content in the leaf tissue but there was a very noticeable difference in the amount of trichomes from the control plant with no UV light vs the one with UVA and one with UVA and UVB.

I read this paper soon after it was released and it's in the "UV does nothing" pile. I skimmed through it just now and can't find anything to substantiate "there was a very noticeable difference in the amount of trichomes from the control plant with no UV light vs the one with UVA and one with UVA and UVB."

It would be helpful if you could quote the sections of the paper that substantiate your assertion.

In addition to the title stating that UV did not impact cannabinoid content, numerous aspects of the study indicating there was no benefit to using UV and the first paragraph of the Conclusion reads:

"Cannabis proliferates at very high canopy LIs in indoor production environments. The increasing inflorescence (and associated cannabinoid) yield responses to high LI in this trial clearly shows the benefits to maximizing canopy-level PPFD within the economical constraints imposed by other production logistics (including input costs). Conversely, we saw no commercially-relevant benefits to exposing cannabis plants to UV radiation." (my emphasis).

There's nothing in this document that would allow me to argue in good faith that there's any value in adding UV to a cannabis growth.

In contrast, there is a significant value in maximizing light levels. The authors assert, in multiple statements, that yield increases directly with increasing light levels. The findings on that topic in this paper echo findings by numerous other researchers and that's one of the reasons why I emphasize to growers, new and experienced alike, to turn up the dial on the dimmer switch on their existing light.

 

[Lovie]

It would be helpful if you could quote the sections of the paper that substantiate your assertion.

It doesn't go into depth about it other than to show a pic of a leaf from each plant but that section of the article allows you to open that section in a new window so here the link to that section I am referring to.

Figure - PMC

Cannabis (Cannabis sativa) flourishes under high light intensities (LI); making it an expensive commodity to grow in controlled environments, despite its high market value. It is commonly believed that cannabis secondary metabolite levels may be ...

pmc.ncbi.nlm.nih.gov

Conversely, we saw no commercially-relevant benefits to exposing cannabis plants to UV radiation.

I know it is not commercially relevant because it didn't raise the THC and CBD levels in the plant tissue, therefore it doesn't increase the value and not worth the expense of adding UV lighting. I am growing on a personal level and I am considering doing this because of the increased amount of trichomes. Also, something not discussed in this article and I need to do more research on it myself but I have read that UV lighting can deter pests and is a good disinfectant. Last year was my first grow and I ended up with spider mites......that really sucked. I live down a long dirt driveway in an old drafty house. Despite my best efforts my house always has some dust.....which I guess spider mites like to hangout. Maybe one day I will be able to do my own experiment......that will be the only way to really tell because even in the article I posted the link to references 2 experiments conducted by 2 different people and every experiment had a different outcome. One of the experiments referenced in this article that was conducted by someone else states UV lighting was detrimental to the plants and the other one claimed it triggered a secondary metabolism response which was beneficial. The author of the article I posted in their findings they did not have a secondary metabolism response nor increase in THC or CBD in the plant tissue. So, pretty much this article discusses 3 experiments with UV lighting all with different outcomes.

In contrast, there is a significant value in maximizing light levels. The authors assert, in multiple statements, that yield increases directly with increasing light levels. The findings on that topic in this paper echo findings by numerous other researchers and that's one of the reasons why I emphasize to growers, new and experienced alike, to turn up the dial on the dimmer switch on their existing light

I don't have any plants growing at the moment but I had the lights turned up when I did! I don't think anyone would disagree with that statement! Or if they have, I haven't come across it! I know you want the lights up as high as your plant will take.

 

[Delps8]

It doesn't go into depth about it other than to show a pic of a leaf from each plant but that section of the article allows you to open that section in a new window so here the link to that section I am referring to.

Figure - PMC

Cannabis (Cannabis sativa) flourishes under high light intensities (LI); making it an expensive commodity to grow in controlled environments, despite its high market value. It is commonly believed that cannabis secondary metabolite levels may be ...

pmc.ncbi.nlm.nih.gov

I know it is not commercially relevant because it didn't raise the THC and CBD levels in the plant tissue, therefore it doesn't increase the value and not worth the expense of adding UV lighting. I am growing on a personal level and I am considering doing this because of the increased amount of trichomes. Also, something not discussed in this article and I need to do more research on it myself but I have read that UV lighting can deter pests and is a good disinfectant. Last year was my first grow and I ended up with spider mites......that really sucked. I live down a long dirt driveway in an old drafty house. Despite my best efforts my house always has some dust.....which I guess spider mites like to hangout. Maybe one day I will be able to do my own experiment......that will be the only way to really tell because even in the article I posted the link to references 2 experiments conducted by 2 different people and every experiment had a different outcome. One of the experiments referenced in this article that was conducted by someone else states UV lighting was detrimental to the plants and the other one claimed it triggered a secondary metabolism response which was beneficial. The author of the article I posted in their findings they did not have a secondary metabolism response nor increase in THC or CBD in the plant tissue. So, pretty much this article discusses 3 experiments with UV lighting all with different outcomes.

Sounds like you've got your work cut out for you!

I don't have any plants growing at the moment but I had the lights turned up when I did! I don't think anyone would disagree with that statement! Or if they have, I haven't come across it! I know you want the lights up as high as your plant will take.

Between this site and two others, very few growers give their plants 800-1000 µmol and superstitions about "turn it up gradually" are the predominant mindset.

That is changing but, overall, growers are very hesitant to turn up the volume. Some of it is cannabis bro science but Shane at Micro and the advice given by growlightmeter.com ensure that growers get modest yields.

 

[Lovie]

Sounds like you've got your work cut out for you!

As much as I would like to conduct my own experiment with UV lighting I do not have enough equipment to. Maybe in a couple of years after collecting more stuff.

Between this site and two others, very few growers give their plants 800-1000 µmol and superstitions about "turn it up gradually" are the predominant mindset.

Last year was my first year growing and I have to admit I did gradually turn it up. I knew I wanted the most light possible without causing stress so I would turn it up.....wait to see if anything happened, then would turn it up some more and so on.

 

[stinker]

Between this site and two others, very few growers give their plants 800-1000 µmol and superstitions about "turn it up gradually" are the predominant mindset.

That is changing but, overall, growers are very hesitant to turn up the volume. Some of it is cannabis bro science but Shane at Micro and the advice given by growlightmeter.com ensure that growers get modest yields.

I'm a firm believer in dialing up the intensity. Never measured but I try and give plants all the light, food and water they can use.
This grow I was going to add a couple UVA, UVB, IR bars for flower. They weren't installed when flipped and then I kept putting it off. I'm considering adding them now, just not sure for how many hours if adding late. Today is day 28 of 12/12.

 

[Lovie]

I'm a firm believer in dialing up the intensity. Never measured but I try and give plants all the light, food and water they can use.
This grow I was going to add a couple UVA, UVB, IR bars for flower. They weren't installed when flipped and then I kept putting it off. I'm considering adding them now, just not sure for how many hours if adding late. Today is day 28 of 12/12.

I personally would be scared to try it being so close to the finish line and with your plants looking so good already. If you do decide to I would start at very low amounts for short periods of time and monitor very closely for signs of stress. If you do it, please share your results!

 

[Delps8]

I'm a firm believer in dialing up the intensity. Never measured but I try and give plants all the light, food and water they can use.
This grow I was going to add a couple UVA, UVB, IR bars for flower. They weren't installed when flipped and then I kept putting it off. I'm considering adding them now, just not sure for how many hours if adding late. Today is day 28 of 12/12.

Nice looking plants!

And an interesting photo, as well.

I believe the praying leaves indicate that you are on the cusp of being at the light saturation point. Leaves may change their shape and attitude in response to light. The mechanism is that auxin moves from the side of the plant that's being hit by photons to the shaded side of the plants. The additional mass on the shaded side causes the leaf to elevate, in the case of praying, or to taco/canoe, in the case of a leaf that's getting too many photons.

What stands out to me in this photo is that the leaves closest to the light are elevating the most and the angle of elevation decreases as you move away from the light//the light levels decrease.

 

[Braddah Waiheesohai]

It doesn't go into depth about it other than to show a pic of a leaf from each plant but that section of the article allows you to open that section in a new window so here the link to that section I am referring to.

Figure - PMC

Cannabis (Cannabis sativa) flourishes under high light intensities (LI); making it an expensive commodity to grow in controlled environments, despite its high market value. It is commonly believed that cannabis secondary metabolite levels may be ...

pmc.ncbi.nlm.nih.gov

I know it is not commercially relevant because it didn't raise the THC and CBD levels in the plant tissue, therefore it doesn't increase the value and not worth the expense of adding UV lighting. I am growing on a personal level and I am considering doing this because of the increased amount of trichomes. Also, something not discussed in this article and I need to do more research on it myself but I have read that UV lighting can deter pests and is a good disinfectant. Last year was my first grow and I ended up with spider mites......that really sucked. I live down a long dirt driveway in an old drafty house. Despite my best efforts my house always has some dust.....which I guess spider mites like to hangout. Maybe one day I will be able to do my own experiment......that will be the only way to really tell because even in the article I posted the link to references 2 experiments conducted by 2 different people and every experiment had a different outcome. One of the experiments referenced in this article that was conducted by someone else states UV lighting was detrimental to the plants and the other one claimed it triggered a secondary metabolism response which was beneficial. The author of the article I posted in their findings they did not have a secondary metabolism response nor increase in THC or CBD in the plant tissue. So, pretty much this article discusses 3 experiments with UV lighting all with different outcomes.


I don't have any plants growing at the moment but I had the lights turned up when I did! I don't think anyone would disagree with that statement! Or if they have, I haven't come across it! I know you want the lights up as high as your plant will take.

Filter your air intake. Cheaper and more effective than UV at keeping pests out.