• UV-A light (320-400nm) is UV light with the longest wavelength, and the least harmful. It is more commonly known as "black light", and many use its ability to cause objects to emit fluorescence (a colored glowing effect) in artistic and celebratory designs. Many insects and birds can perceive this type of UV radiation visually, along with some humans in rare cases such as Aphakia (missing optic lens).
• UV-B light (290-320nm) causes sunburns with prolonged exposure along with increasing the risk of skin cancer and other cellular damage. About 95% of all UV-B light is absorbed by the ozone in Earth's atmosphere.
• UV-C light (100-290nm) is extremely harmful and is almost completely absorbed by Earth's atmosphere. It is commonly used as a disinfectant in food, air, and water to kill microorganisms by destroying their cells' nucleic acids.

Chad.Westport said:

• UV-A light (320-400nm) is UV light with the longest wavelength, and the least harmful. It is more commonly known as "black light", and many use its ability to cause objects to emit fluorescence (a colored glowing effect) in artistic and celebratory designs. Many insects and birds can perceive this type of UV radiation visually, along with some humans in rare cases such as Aphakia (missing optic lens).
• UV-B light (290-320nm) causes sunburns with prolonged exposure along with increasing the risk of skin cancer and other cellular damage. About 95% of all UV-B light is absorbed by the ozone in Earth's atmosphere.
• UV-C light (100-290nm) is extremely harmful and is almost completely absorbed by Earth's atmosphere. It is commonly used as a disinfectant in food, air, and water to kill microorganisms by destroying their cells' nucleic acids.

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Paul_morphy said:

I need some info on uva leds. Ive been looking at the hlg uva bar and the eco farm uva/ir/far red bar. Hlg says it will cover up to a 5x5, which is what i have, with one bar running for 12 hours on and uses 365nm and 385 nm diodes and costs 120 (currently on sale from 150). Eco farm says you should use 2 bars at 100 a piece and only run them for short periods not 12 hours and theyre 395 diodes.

I guess what im asking is what is the best uva led light i can get. What is the best nm for the diodes. Are 395 diodes good enough. Hlg uses top bin 365nm true uv light. And how long do you guys run your uv? Is it the full 12 or in short bursts? Please help, thank you.

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Igrow_it said:

Hey, so I didn't read all the replies, so maybe someone else said what I'm about to say, but as far as the uv spectrums go (meaning uva,uvb and uvc) uva is really the only one that has any meaningful benefits to cannabis, now that's not to say that uvb or uvc don't have a part, but uvb is kinda dangerous, especially over time, and depending on exposure, could lead to cancer. Now uvc is basically blocked out totally by the sun because it would literally sterilize the planet lol, uvc is the light spectrum used in industrial cleaning bulbs in hospitals for instance, and are highly dangerous if exposed for even a few minutes in high enough doses. Uva however, if used in a full 12/12 cycle (speaking strictly for the hlg 30 watt uva supplement bulb) as soon as the plant starts to produce its own trichomes (usually around week 3 or 4) will interact with the surface of the plant, forcing it to produce up to 15 percent (according to certain clinical studies) more thc/terpenes as a natural defense to protect from the harsh uva rays, cannabis is the only plant known to react like this, producing its own form of "sunblock". The benefits of uva are undeniable now, especially with so many more people growing and experimenting. I can personally say that the hlg 30 watt uva bulb has worked great for me so far. Timing I would say is the most important aspect of uva usage I suppose. Just make sure your babies have trichomes like I said beforehand, then as soon as they do, you're good to go, keep em around 12 to 18" away from the canopy too if you can, as they are not adjustable.

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Igrow_it said:

Hey, so I didn't read all the replies, so maybe someone else said what I'm about to say, but as far as the uv spectrums go (meaning uva,uvb and uvc) uva is really the only one that has any meaningful benefits to cannabis, now that's not to say that uvb or uvc don't have a part, but uvb is kinda dangerous, especially over time, and depending on exposure, could lead to cancer. Now uvc is basically blocked out totally by the sun because it would literally sterilize the planet lol, uvc is the light spectrum used in industrial cleaning bulbs in hospitals for instance, and are highly dangerous if exposed for even a few minutes in high enough doses. Uva however, if used in a full 12/12 cycle (speaking strictly for the hlg 30 watt uva supplement bulb) as soon as the plant starts to produce its own trichomes (usually around week 3 or 4) will interact with the surface of the plant, forcing it to produce up to 15 percent (according to certain clinical studies) more thc/terpenes as a natural defense to protect from the harsh uva rays, cannabis is the only plant known to react like this, producing its own form of "sunblock". The benefits of uva are undeniable now, especially with so many more people growing and experimenting. I can personally say that the hlg 30 watt uva bulb has worked great for me so far. Timing I would say is the most important aspect of uva usage I suppose. Just make sure your babies have trichomes like I said beforehand, then as soon as they do, you're good to go, keep em around 12 to 18" away from the canopy too if you can, as they are not adjustable.

Click to expand...