UV Light Basics – Cannabis Growing Lessons

Today on Lex’s World I discuss the the UV portion of the light radiation spectrum and how it might concern you weed growers out there (spoiler; usually, …


  1. I just stumbled across some CFL 23watt UV bulbs. The glass spiral tube is black rather than white. i wonder if throwing a couple of these in the grow room would do any good or not?

  2. You’re stuck in 2016 as far as LED grow lights go. If you get correct LEDs (Samsung, Cree, Osram, lg), they blow HID and HPS out of the water in every way… YES even in yield

  3. The use of UVB without a doubt significantly increases resin production. This isn’t a matter of you not being convinced, it’s a matter of what overwhelming evidence shows. Said plants produce resin as a defense mechanism (like sunblock) against uvb (or any uv). So yes, resin production significantly increases with the addition of uvb into the spectrum.

  4. Mine burned on 4 leaf's of my plant and I was scared so I let them turn brown and crusty cut them off and now dont know if they will re grow

  5. WRONG!! All WRONG!!! What, does this guy think I’m an asshole or something?!? Is This guy TRYNA fuck our girls??!

  6. How is uv dangerous unless people are to retarded to have a switch outside so you can switch it off before entering the room.

  7. We receive more and more reports of growers who use the CleanLight Pro daily to strengthen their plants. A few seconds per day mimics the effect of natural sunlight.

  8. Hey Lex, thanks for all your growing videos. You sure are an experienced grower, but this episode is not quite accurate and incomplete. First, LED lights, blue and or white (phosphoruscoated commercial white) all produce sufficient UVA spectrum. Second UVB has been shown to increase resin and THC production. Plant sunscreen if you want. Just don't overdo it. Third I recomend supplementing any grow light, HID, Fluorescent and LED with UVB spectrum during flowering. For this I reccomend running a Mercury Vapor lamp for a few hours 4 to 6 hrs per day in addition to whatever you use. MV lights emit UVA and UVB in addition to visible light. They are cheap, long lasting and almost as efficient as fluorescents and easy to use e27 socket self ballasted. They are great for the last 2 weeks of flowering too for ripening off your buds. Some growers use metal halide for ripening but I strongly recommend mercury vapor for this because of the UVB. Just run it in addition to whatever you have it will bluen up your visible blue spectrum which creates more resin and terpines. The tradeoff is that more red spectrum makes for denser indoor style buds, thats why only blue up the spectrum in the last 2 weeks significantly. But do use MV lamps for the entire flowering period because of the UVB. Just don't overdo it. If you get lightburn you know its too much. Start with 2 hrs per day and work your way up.

  9. @Lex Blazer Hi Lex Please help??? Can a Mars Hydro Reflecor 480w grow , without having UV/infared , grow decent enough plants , plants?? My friend has one and now shhez freakin out sayin "everone says Mars is good but it dont have UV/IR , I dunno know?? Lol

  10. hey, you can get some really nice diy uv leds, drop white leds in dichloromethane until the epoxy with the yellow phosphorus come off, then submerge the leds in acetone with some 30% of nail transparent base just to get a thin protection over the led diode.

  11. Please update this. UV makes resin. This has been known for generations. Afghanistan, and other higher elevations with more UV, produce outdoor crops with more resin. The oils are the plants' sunscreen. Facts.

  12. i dont have a par meter. how many lux of cold white and blurple led light woud be too many lux to be over the harmful +1200 par range? is there a way to calculate it.

    the hydrofarm par meter costs ~$150 but it's got 40% of 1-star reviews on amazon, very poor quality that either doesn't work or has to be fixed so I don't wanna risk the money. of course a good par meter would fix this issue. thanks to anybody that knows.

  13. Iv got a couple i put in flower under a hps 400 iv been taking it outside to get some good sun while the other 2 ripen up. Do ya think i could do more harm than good by going in and out ?

  14. Shorter wavelength lamps are also used to erase EEPROMs. Great video again! One thing about short wavelength UV is that it's easily blocked and filtered by even "transparent" glass or plastic. Of course Its common sense to wear safety glasses around these high intensity LED lights.

  15. I just want to see a UVB lamp but there is such a craze for cannabis, same with looking up techniques for growing pepper plants. Not complaining. Legalize it.

Leave a Reply

Your email address will not be published.