The Effects of UV light on Cannabis Production and Potency

botanyofdesire

Active Member
I was doing a Google search on something and stumbled upon an old thread here that had some discussion about UV light. Some people were very fast in there belief that UV has no effect on plants, well others, one even said Ed Rosenthol claimed that UV light would increase potency.

For some reason this debate seemed to stop inconclusively. I am new to this forum and apologize if the topic has already been brought back up and I am just unaware of it.

However this is a very interesting topic. So, what are your ideas? Do you have any information regarding the effects of UV light on cannabis growth or potency? Lets get that debate rolling again.

I have found this information (extracted from http://www.cannabisculture.com/articles/2696.html):

A researcher conducted a controlled experiment in a greenhouse. He lit a group of high potency plants similarly except with the addition of UVB light to some groups. He found that the percentage of THC increased in a direct ratio with the increase in UVB light. This research confirms the adage that high altitude plants are more potent than those grown at low altitudes.
If you look at old-world land races of cannabis, plants that have become adapted to the climate and latitude, the ratio of THC to CBD starts at 100 : 1 at the equator. At the 30th parallel (The Hindu-Kush Valley) the plants have a ratio of 50 : 50. At the 45th parallel the ratio is near 1 : 100. This corresponds roughly with the amount of UVB light received at these latitudes. There is much more UVB at the equator than the 45th parallel.
How can you get more UVB light to your plants? Certainly it's true that MH lamps emit more UVB light than HPS lamps. Still the amount that MH lamps emit is small. In fact, many manufacturers use UVB shielding glass to filter out most of the UVB that's produced. The UVB light the plant receives from an MH lamp does increase the plant's potency slightly at the cost of yield, but there are better ways to introduce UVB light into the grow room. They include reptile lights, which emit about 10% UVB, and tanning lamps.
The problem with using these lamps is that they are associated with increased number of cancers and many other problems. They should not be on when you are in the grow room. Not much research has been conducted on using them to produce higher THC values. I will do a full report in a future issue.
 

Buddist

Active Member
This is an important piece of info!

It is assumed that THC is produced to protect the cannabis from herbivores. It also has been discovered that the crystals block UVB 275nm - 325nm range - the most harmful part of the electromagnetic spectrum.

Im no science wiz but it seems logical that any plant with these features might just produce more trichomes if threatened by UVB:leaf:

Low presure mercury vapour lights (flourecent) have a coating on the inside of the tube to convert UVB into less harmful wavelenghts.

Im going to elevate the UVB on a few on my flowering girls. YIK!

Stay tuned!
 

curioushiker

Active Member
Why did this thread die? This is a very interesting idea.
Are there any new discoveries about UV lights and canabis?
 

MEANGREEN69

Well-Known Member
nice thread, i read some were that grew at i higher elevation were more potent but yeilded less then the plants that grew at a lower elevation...
 

Yota

Well-Known Member
There are some very lengthy threads and info on this if you do some searching around
 

odin92681

Member
The whole LED area is new to all of us and it's important cause it would cut our electricity by $$$ not cents. We just need more data to be proved that if works.
 

BobCajun

Well-Known Member
I saw a study that showed that plants grown with maximum UV were only about 25% more potent than ones with no UV at all. This proves that UV is not required for decent potency (as LED growers would know) but does make a little bit of difference. Since the UV is also dangerous to the grower, I would stick with normal lights myself but an extra 25% potency might be worth it to some people.
 

Jerry Garcia

Well-Known Member
I saw a study that showed that plants grown with maximum UV were only about 25% more potent than ones with no UV at all. This proves that UV is not required for decent potency (as LED growers would know) but does make a little bit of difference. Since the UV is also dangerous to the grower, I would stick with normal lights myself but an extra 25% potency might be worth it to some people.
ONLY 25%!?!?!?!?!?!?! Make a little bit of a difference?

Who doesn't want an extra 25% potency?
 

Ap0c0leS

Active Member
Ive heard about this as well and , from a very reliable friend. He claims the side of the plant faceing his UVB 10.0 Reptile bulb was coated with Trics, He said he had to rotate the plant towards the light to finish the other side. ! I also bought a light and if you believe this about UVB light helping plants. There is also some info and experiments useing Infared lights to * spray * the plant with photon's ( light) and make it instantly go to sleep during the dark cycle. So in theory, you could set your Infared light to come on right as the lights go off. This would , according to Ed rosenthal ( also does UVB experiments) Put the plant into an instant state of sleep, instead of it taking the standard 2 hours for the plant to reach a sleeping state. Basically even if your set at 12/12 your plant is only getting 12/10 because it takes two hours to completely convert to sleep. Useing an Infared light as your plant lights go off could increase the sleep time your plants are aloud by a total of 2 hours. Increase in yeild by far anyone? Thats what? 20 percent more sleep?
 

m23mark

Active Member
I have recently started a new grow (white widdow) and i am going to give this UV lighting a try on a small number of plants just to see if it does effect the potency compared to the lights grown under 600 watt HPS lights alone.

Does anybody have any suggestions on what type of UV light to use? I am thinking of buying a UV strip light from a pet shop and plugging it into a timer so it is syncd with the HPS lights.. think i will just use it for the flowering cycle.

Any advice before my plants finish vegging would be most appreciated folks??
 

MAXXDANK

Member
I saw a study that showed that plants grown with maximum UV were only about 25% more potent than ones with no UV at all. This proves that UV is not required for decent potency (as LED growers would know) but does make a little bit of difference. Since the UV is also dangerous to the grower, I would stick with normal lights myself but an extra 25% potency might be worth it to some people.
By 25%...who said that, you need to list your sources, you cant jump in and throw numbers around and not list your sources.....
 

Thedillestpickle

Well-Known Member
Hey guys, am I right to think that a 6500K metal halide bulb produces UVB? i know they are reported to produce less but more potent bud when used during flower. Im trying to find a 600w Metal halide bulb but having no luck, are they around? I want it to be a true MH bulb for what im trying to use it for, not looking for a HPS bulb with a bluer spectrum. Whats the deal did they not make a 600w MH? thanks much for the help
 

george xxx

Active Member
.

Does anybody have any suggestions on what type of UV light to use? I am thinking of buying a UV strip light from a pet shop and plugging it into a timer so it is syncd with the HPS lights.. think i will just use it for the flowering cycle.

Any advice before my plants finish vegging would be most appreciated folks??
Check the light and do your home work prior to purchasing a UV light. Some are not to be used with electronic timers. I have no idea why. I just know that it's stated on some UV lights.
 

cannator

Member
These are my plants in day 12 of bloom. I bought a reptisun 10.0 UVB Lamp to add to the 300W LED PANEL RBO 7:1:1. I will update with results.

Greetings.

fzan9j.jpg
 
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