UV Light and plant growth

[SHRED]

I sent an email to an LED manufacturer asking if their lights emitted ultraviolet light waves.

This was the reply:

"All our lights are full spectrum. Before we developed the light, we made repeated experiments and found that the ultraviolet light has little effect on plants, so the content of ultraviolet light is relatively less.
Hopefully it wil be helpful to you."

I have read that UV rays help with trichome production and overall growth.

Now I'm confused.
Does UV help or not?

 

[Humanrob]

I've read it does, I've read it doesn't (and then the subsequent discussions about UVA vs UVB). I ordered one that is going to be delivered today... so I'm curious how this thread goes. My expectations aren't high, I just hadn't upgraded my home-built lights in years and had an itch to make a change. Hopefully by the end of the thread I won't have buyers remorse...

 

[SHRED]

I've read it does, I've read it doesn't (and then the subsequent discussions about UVA vs UVB). I ordered one that is going to be delivered today... so I'm curious how this thread goes. My expectations aren't high, I just hadn't upgraded my home-built lights in years and had an itch to make a change. Hopefully by the end of the thread I won't have buyers remorse...

I just saw this:

UV Light

 

[Humanrob]

I just saw this:

UV Light

Interesting video. I'm not knowledgeable enough to confirm or refute anything he said, as has been the case through many of the threads I've read on the subject. At least the guy in the video stuck with 'probable' or 'possible' when he reached the edge of his own verifiable information.

A few years ago I had several tents and was growing year round and trying a lot of things. The closest I came to working with UV were a few runs I did with 'lizard lights'. They did seem to make the plants frostier, but the logistics in my setup was not worth it (they were cumbersome clamp-on lamps). The things I tried back then were not "experiments" because I was trying new strains and sometimes new techniques every grow, so there were no side-by-side comparisons or even any continuity between grows.

At this point I'm just playing around, I'll add this purpose-built supplemental light to my setup and see what happens. At least practically speaking, it will be easier to work with than my previous attempts.

 

[psyshack]

All UV will do is possibly spur the plant to put on more sunscreen by way of trichomes. And even that is very strain/genetics specific. Does not always work and can sometimes hurt. Been using it for years. And currently have UVA on my dual 350R and 650R. Only run them during flower and only 4 to 6 hours a day in the middle of the day time light cycle on there own timers.

 

[Badfinger]

I been using 100w boards since my first grow. I been researching for a new light in the future. Mainly I been looking at Spider Farmer and Marshydro with what I refer to as bar lights, the ones with removeable drivers.
I find it weird their lights only offer UV up to 480w, after that the big lights don't have them. Almost as if it's some fad their offering to home growers.

 

[Olderfart]

I sent an email to an LED manufacturer asking if their lights emitted ultraviolet light waves.

This was the reply:

"All our lights are full spectrum. Before we developed the light, we made repeated experiments and found that the ultraviolet light has little effect on plants, so the content of ultraviolet light is relatively less.
Hopefully it wil be helpful to you."

I have read that UV rays help with trichome production and overall growth.

Now I'm confused.
Does UV help or not?

I doubt that it makes a lot of difference, but do not have the setup or time to do a proper test. A proper test would be with a sample of identical clones, and a double blind test of the resulting bud. I do not believe that the difference would be reliably identified by using seeds, there is just too much variation within strains to detect and quantify effects. Double blind testing of the bud is necessary. No one is immune to wishful thinking after spending hundreds of dollars on new lights. As mentioned above, strains likely vary, so proper testing would repeat the test sampling for multiple strains, all via clones. There are other design considerations, but the main thing is sample size, and how the product is tested.

In my opinion, the first priority is having enough light to give all your plants ~60DLI during the daylength being used. The exact wavelength composition is, I suspect, a lot less important than having enough of it everywhere in the grow space. The balance between blue and red ends of the spectrum will mostly affect the growth form, more blue will be squatter, more reds, more stretchy.

All just my two cents worth of course.