UV light or photoinhibition

Greenthumbs21

Greenthumbs21

Well-Known Member
DankaDank said:
Im a bit conflicted regarding this topic, this reddit thread seems to make sense https://www.reddit.com/r/Head2HeadMG/comments/2nt3ml/red_white_blue_full_spectrum_an_led_color_choice/
but then there's this
http://medicalmarijuanagrowing.blogspot.co.uk/ wich is apparently an actual test (just read from the third page and scip the mildew shit).
The dankest strains do come from high altitude areas so could it be more uv or simply more light or even different atmospheric conditions and lower altitude areas seem to have more cbd rich strains, so maybe uva and b are detrimental to cbd ,so many questions and so little tests better get my shit together and start some test journals :joint::bigjoint:
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Think of light photons as a little ball flying through space. At high altitude the ball has to travel through less clouds and atmospheric particulates so the plant gets more direct sunlight. Just like dawn and dusk... the photon has to shoot across the atmosphere whereas high noon the photon just drops straight through the atmosphere(highest uv concentration)
 
BobCajun

BobCajun

Well-Known Member
Rayne said:
If you want the plant to develop to it's fullest genetic potiential. UV A/B light and Infrared light must be included.

Outdoor Sativa strains get bathed in UV A/B plus infrared red and still grow at least 10 foot tall.
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I was actually wrong when I said UV-B would reduce growth. Apparently Cannnabis is immune to it, due to the cannabinoids. Here's the article.
 
DankaDank

DankaDank

Well-Known Member
Greenthumbs21 said:
Think of light photons as a little ball flying through space. At high altitude the ball has to travel through less clouds and atmospheric particulates so the plant gets more direct sunlight. Just like dawn and dusk... the photon has to shoot across the atmosphere whereas high noon the photon just drops straight through the atmosphere(highest uv concentration)
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Thats actually how i think of it as well lol, but sub 400 nm photons are not the only photons to loss energy from distance so therefore theoretically there is more light (not just uv) at higher altitudes.
 
~CReePeR~

~CReePeR~

Well-Known Member
OK so I purchased 2x26w 10.0 Desert Reptbulbs. Here are my results.

My setup was 16 Hydro Buckets 8 on 1 side and 8 on the other all running off the same reservoir. Each side had 2x1200 watt LED and 1x800 watt COB. Basically both sides were exactly the same. 1 Side had the 2 UVB Bulbs hanging vert about 8-10 inches from plants
I noticed no increase in trichomes on the side with the UVB bulbs.
But when I harvested I noticed a huge sticky resin increase while I was trimming the plants closest to the UVB Lights

So I figure the resin increase was due to the UVB. A Bonus if you make BHO from your bud.
 
Greenthumbs21

Greenthumbs21

Well-Known Member
~CReePeR~ said:
OK so I purchased 2x26w 10.0 Desert Reptbulbs. Here are my results.

My setup was 16 Hydro Buckets 8 on 1 side and 8 on the other all running off the same reservoir. Each side had 2x1200 watt LED and 1x800 watt COB. Basically both sides were exactly the same. 1 Side had the 2 UVB Bulbs hanging vert about 8-10 inches from plants
I noticed no increase in trichomes on the side with the UVB bulbs.
But when I harvested I noticed a huge sticky resin increase while I was trimming the plants closest to the UVB Lights

So I figure the resin increase was due to the UVB. A Bonus if you make BHO from your bud.
Click to expand...
They are technically for supplementing hps with low nanometers. .. your leds already have lower nanometers and some have built in uvb.
 
BobCajun

BobCajun

Well-Known Member
DankaDank said:
Im a bit conflicted regarding this topic, this reddit thread seems to make sense https://www.reddit.com/r/Head2HeadMG/comments/2nt3ml/red_white_blue_full_spectrum_an_led_color_choice/
but then there's this
http://medicalmarijuanagrowing.blogspot.co.uk/ wich is apparently an actual test (just read from the third page and scip the mildew shit).
The dankest strains do come from high altitude areas so could it be more uv or simply more light or even different atmospheric conditions and lower altitude areas seem to have more cbd rich strains, so maybe uva and b are detrimental to cbd ,so many questions and so little tests better get my shit together and start some test journals :joint::bigjoint:
Click to expand...
Good links. So red LEDs around 620-630 nm are cheap and efficient. Makes sense to use mostly them then and only a few whites or blues.

In the UV blog post it's odd that it says CFL UV bulbs don't work, because I've seen the fluorescent tubes he uses (in his YT vids) and the intensity they put out is very low. They have to be no more than a couple inches away whereas the CFLs have the same intensity several inches away.
 
RM3

RM3

Well-Known Member
I run UV thru out, including seedlings just like outside and have for years. I also flower with T5's so I can alter the ratio of the spectrum to see the effects and I can tell you after years of doing this that ,,,,,,,,,,,,

Deep blue grows/increases trics not UV

UV increases potency

1st pic, one week old seedling, 2nd pic same seedling week 2
.
1rtn.jpg 1rtn2.jpg
 
Rrog

Rrog

Well-Known Member
Cannabinoids don't lend UV resistance. While Cannabinoids may increase due to exposure to UV, that's not to protect it from UV.
 
BobCajun

BobCajun

Well-Known Member
RM3 said:
UV also matures the trics faster, here is a bud at 6 and half weeks
.clic to zoom and see the amber
View attachment 3678148
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As can be seen from the pics, if you use UV the whole life of the plant from seedling the leaves won't get browning on the margins like they will if you only hit them later.

For those who deny that UV-B increases THC, this is a pretty definitive article, though admittedly only using 2 strains. In fact, it not only increased THC in buds but also in leaves. The UV also had no negative effect on growth, as it does in many other plants. Seems to be no downside.

Also interesting how graphs show increase in growth pretty much flatlines after about 900 PPFD.
 
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Greenthumbs21

Greenthumbs21

Well-Known Member
BobCajun said:
As can be seen from the pics, if you use UV the whole life of the plant from seedling the leaves won't get browning on the margins like they will if you only hit them later.

For those who deny that UV-B increases THC, this is a pretty definitive article, though admittedly only using 2 strains. In fact, it not only increased THC in buds but also in leaves. The UV also had no negative effect on growth, as it does in many other plants. Seems to be no downside.

Also interesting how graphs show increase in growth pretty much flatlines after about 900 PPFD.
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The only possible downside is in the genetics and cloning. Uvb and c cause a bulge in the DNA helix. So if you clone over and over you may get drift or problems but thats about it. It definitely increases potency and changes the chemical make up of the trich. The cuticle on the trich is expanded for more protection
 
toaster struedel

toaster struedel

Well-Known Member
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BobCajun

BobCajun

Well-Known Member
Greenthumbs21 said:
The only possible downside is in the genetics and cloning. Uvb and c cause a bulge in the DNA helix. So if you clone over and over you may get drift or problems but thats about it. It definitely increases potency and changes the chemical make up of the trich. The cuticle on the trich is expanded for more protection
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I didn't notice any increase in potency when I used reptile CFLs last crop. I put them very close too, like 8", 26 watters, and with aluminum reflectors. I was also using EOD far red so I think that might actually have interfered somehow. This time I'm using them with EOD red. I'll see if that helps. I did read that in some other plants EOD red increased phenylpropanoids by 6%. Things that increase phenylprops would likely also help with THC, since both are "secondary" products. UV is also supposed to increase them. So EOD red may be additive to the UV effect.
 
RM3

RM3

Well-Known Member
BobCajun said:
I didn't notice any increase in potency when I used reptile CFLs last crop. I put them very close too, like 8", 26 watters, and with aluminum reflectors. I was also using EOD far red so I think that might actually have interfered somehow. This time I'm using them with EOD red. I'll see if that helps. I did read that in some other plants EOD red increased phenylpropanoids by 6%. Things that increase phenylprops would likely also help with THC, since both are "secondary" products. UV is also supposed to increase them. So EOD red may be additive to the UV effect.
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I have been saying for years the reptile bulbs have little benefit, have only found a few bulbs that actually work. Had a friend with a UV meter that tested a bunch of em
 
BobCajun

BobCajun

Well-Known Member
RM3 said:
Those numbers look ok, the test he ran was a few years ago
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The figure for 1 foot is no higher than probably outdoors in temperate zones but it must be pretty blistering at 6" or less. With the Exo 150 they'd have to be about 4" away. I didn't have them that close but the reflectors should have helped. The higher version, 200, has twice as much UV but they're hard to find in stock anywhere. I had to take the 150s.
 
Rrog

Rrog

Well-Known Member
Greenthumbs21 said:
Uvb and c cause a bulge in the DNA helix. So if you clone over and over you may get drift or problems but thats about it.
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Plants have constant repair mechanisms for UV exposure, including the "bulging" (pyrimidine dimer) you mention. This is a hazard for humans, not so much for plants.

I suspect the cloning "drift" people describe occasionally as being attributed to the lack of UV over generations, not the exposure to UV. Over the last buncha years, most indoor grows haven't seen much UV at all.
 
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