Help regarding choosing solution for adding UVA/UVB LED's to a DIY COB LED grow light.

Discussion in 'LED and other Lighting' started by Planet Tomato, Jul 18, 2018.

  1.  
    Sparky123

    Sparky123 Well-Known Member

    God dammit I just started at the 69min mark on this like and ended up starting the hole thing
     
    SSR likes this.
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    Airwalker16

    Airwalker16 Well-Known Member

    I absolutely can not stand tricky-d and all of his bullshit whining and crying.
     
    Sparky123 and SSR like this.
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    SSR

    SSR Well-Known Member

    Me either but there was info to be had. If I knew how to start videos at time stamped points I'd have done that
     
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    Airwalker16

    Airwalker16 Well-Known Member

    Glad I'm not alone in that thinking. I don't feel like such an asshole now.
    But geeeeeeez he's Sooooo mentally unstable in his videos. I want to punch him square in the face
     
    Last edited: Mar 14, 2019
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  5.  
    Randomblame

    Randomblame Well-Known Member


    Sorry, I have to disagree with that blue light UVA skiddles nonsense.
    There is an UVR8 receptor in cannabis plants you can trigger with UVB light between 280 and 300nm (285nm has the strongest effect) but there is no way to trigger this receptor with UVA or simple blue diodes no matter how many skiddles you feed them per day.
    This receptor tells the plant to switch in a kind of stealth mode to produce more THC to protect the next generation of seeds from getting damaged by too much UV light. That's a natural mechanism and only plants are affected that grow near the equator or in heights above 1000m. Cyclamens and other species have also developed mechanisms to protect themself.
    There is a reason why the strongest strains are typically found in this areas.

    With more blue light the buds stay more dense but the plant still produce the same amount of trichomes so the trichome layer also look more dense. No?
    Purple and UVA wavelength can cause a stronger or even a complete different smell cause they increase and change the terpenes and their profile. Terpenes have also effects on the stone and a changed terpene profile can change the feelings you get from smoking it. It can feel stronger even if the thc content stays the same. If have seen recommendation where the breeder said, give them some extra week of pure blue light and you can increase thc by 30%. I've tested it.. two times. and what shall I say..? I does nothing special. The extra week has brought much more colors to life but the smoke was almost the same.

    Believe me, to really increase the thc content in dry mass you need to trigger this fucking UVR8 receptor otherwise there is no increase in thc. I recommend to read the wiki about the UVR8 receptor. Google is your friend..

    I've harvested UVB supersilverhaze and a columbian gold 3 month ago and when I've smoked them the 1st time I got heart palpitations so trippy was it. I needed a few days to get used to it, lol. No joke!
    Now I'm having fun knocking my friends out of their socks...

    Try it out, babe! Such a T5 reptile bulb fits in every T5 housing of the same wattage. For a 2x 2' area you need to 2ft/24w bulb. A 12% reptile bulbs like Arcadia's d3desert can run all day long because their UVB light only reach ~295nm. You can also use the Agromax 2ft PureUV in the same 24w fixture but these are 10 times stronger and the light goes down to 275nm at least. One hour per day is already enough and more is already harmful and can damage the plant. They also need a minimum distance of 24" otherwise you get heat stress up to curled, twisted or wilting leaves. That can happen in only one day! Remember, 275nm is already UVC..
    I know growmau5 has used such Agromax bulbs, two of them on his canopy10 light and I think he has not figured out a way to use them properly. I've a dimmable ballast to have more control over their output and the daily UVB dose at canopy level.
    But such a reptile bulb costs around 20 bucks and a T5 fixture you can find on the scrap yard or you build something yourself. You only need 2 bulb sockets, some single core wire and a T5 ballast, another 20$ maybe. But you can also take every 24w T5 fixture from walmart and simply change the bulbs.
     
    Last edited: Mar 14, 2019
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    Airwalker16

    Airwalker16 Well-Known Member

    I think I might just get 2 sun blaster single bulb fixtures and try running the desert bulb all day long this flower run. What bulb do you recommend is truly best @Randomblame ? And do you think all day low lvls or short 1HR a day high UVB is better?
     
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    Randomblame

    Randomblame Well-Known Member

    The brand depends on your location. For US peeps I would say get the Agromax powerveg+ bulb. They have a similar spectrum like a 12% Arcadia bulb. Reptisun should also be available but has only 10% UVB.
    I would start using it a few days before your push the flower switch to give them time to get used to it. I would start with 1h in the morning and 1h right before lights off. Far-red end of day treatments are not affected by UVB and 5 mins after lights off is still working.
    When they are used to it which takes up to a week you can increase the hours per day slowly. When I see the first upcomming trichomes I would use them 2x 3h per day and increase that by another hour the week. So from ~week 3 six hours and from week 8 you can use it all day long to push them to the limits.
    12" is a good distance cuz its a 360° bulb and when you use a 120° reflector they cover exactly a 2' wide area. Center readings are almost twice as high as the intensity on the outer ends of the area for this reason I put the shortest plants in the center and the higher ones on the sides to even it out a bit.
    You can also use it earlier for the whole day but IMO its wasted energy. Even if the dose princip is not working properly with the different spectrums of pureUV and reptile bulbs, the calculated dose is pretty high.

    That's a test with an Arcadia D3deseet with 12% UVB and 30% UVA, bare bulb and with 3 different kind of reflectors.(pdf below) I like the hammered reflector because it has the best distribution even if the center readings are lower. You see ~150μW/cm² at 12"/30cm, the average is probably only 100μW/cm². To calculate the daily dose in kJ/m² you only need to multiply the total microwatts per day by 0,036. 6h á 100μW/cm² is 600μW x 0,036 thats already a dose of 21,6kJ/m² per day. Screenshot_20190314-204809.png

    The thing why you can't use this method for the pureUV bulbs is their spectrum goes down to the bottom of the UVB range and hits already UVC. 10nm less in this area means the photons carry 10x more energy and in general one can say the more energy in stored inside the photons the more dangerous they get.
    X-rays have so much energy that they just go through you and gamma rays would just burn you your ass off.

    Below is the full test report to give you some numbers to work with and I will also add a research paper about UVB and what you can expect. They have use a UV burner and have used an additional UVC filter to remove UVC wavelength. So their calculated doses per day are also not comparable with the PureUV bulbs unless you find a UVC filter coating to paint the bulbs with. There are also two lab tests, same strain, same light and enviromental conditions, one with the other w/o UVB.
    UVB won and they have only used a dose of 13,4kJ/m². With 6h per day you are already on the high side, with 12h the dose would be 43,6 fucking kJ/m². Mexico city, which is near the equator AND 2000m above zero recieves for instance such a high dose per day and the intensity at noon can reach 450μW/cm²!

    If you do it this way, make them used to it and increase slowly, keep ~10-12" distance and so on I guarantee you 100% success! It works and the easiest way to prove it is to split your tent in 2 areas and use only on one area additional UVB.
    Same genetic on both sides! I've done the same and with the 2nd run I've added it already to the whole tent and I will never look back. If you have a good rosin press with consitent results you can make a test by yourself and weight the outcome. Pretty sure the UVB weed yields better!


    Edit:
    Reptile or powerveg+ bulbs are much better for UVB beginners because even if you burn the plants a little you wont lose your whole crop. Agromax bulbs are so strong that even one day with too much can cause a flowering stop and you end up with extremely potent weed but only half as much yield as usual.
    Ahh, and make sure the reflector has a metallic surface like hammered or polished aluminum. Paint, plastics, glas and all that swallows UVB completely. The best would be a wing design to get the most even distribution. I've also build so called super spreader(know from the adjust a wing) to reduce the center hotspot by throwing a part of the light back into the reflector to distribute it evenly. But nevertheless I've burned my plants on the 1st run with two PureUV bulbs
    although I was extremely careful. They are unduly simply too strong for 16-18" distance even with the spreaders. So stay with the powerveg+ bulbs, they are strong enough and you get the same results. It only takes more energy.
     

    Attached Files:

    Last edited: Mar 14, 2019
  8.  
    Airwalker16

    Airwalker16 Well-Known Member

    And I've contacted that company for those 50cm strips twice now and they have yet to respond to whether they ship to the USA or not.:confused::wall:
     
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    Airwalker16

    Airwalker16 Well-Known Member

    Very cool information. I guess the powerveg is a better option than pureuvb. I plan on only using 1 2ft bulb and fixture per 4X4. So I'd probably have it the same height as my LEDs and just have it on all day by the 3rd week. Ramping up a half hour a day or so the first 2 weeks.
     
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    Randomblame

    Randomblame Well-Known Member

    Hmm! A 2ft bulb is probably not enough for a 4x 4' area. Only the plants in the middle would recieve enough UVB. And with 24" distance the intensity would be less than 50μW, average less than 30 probably and in the corners there would be almost no UVB light.
    Better test it on a siutable surface area and leave the rest without UVB. Maybe 2,5 x 2' so god will but only this way you get the full UVB effect and when you're happy with the outcome you can add another pureveg+ with the next run.
     
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  11.  
    Airwalker16

    Airwalker16 Well-Known Member

    So if I plan on having it at led height around 12-24" usually the high side, ashoud I try pureuv bulbs for like 4 middle hours of the 12/12?
     
  12.  
    Renfro

    Renfro Well-Known Member

    Hey I got a few of these sitting around, bought them for some rick and morty posters that I have. Do you think they would do anything in my flower rooms or just a waste of space?

    192 x 0.25 watt uv leds

    https://www.chauvetdj.com/products/led-shadow/
     
  13.  
    mr. childs

    mr. childs Well-Known Member

    "Agromax bulbs are so strong that even one day with too much can cause a flowering stop and you end up with extremely potent weed but only half as much yield as usual." very honest & true statement, ive been going through for years. and to think htg used to make a 100%uvb bulb. only thing i disagree on brother is using the 2ft pure in a 4x4. hang it as high as you can from day one in veg to get them acclimated, and ride it out to the razors edge, then back off with a separate timer until the end.
     
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    Airwalker16

    Airwalker16 Well-Known Member

    Would you detail further what you mean?
     
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  15.  
    mr. childs

    mr. childs Well-Known Member

    @Randomblame said the agromax bulbs are too strong, i agreed. when used too much they definitely reduce yield, but make bud that will have you hallucinating. for years i have been using a single 2ft in the middle of a 4x4 at the very top of the tent. in years past i used a 2ft bulb in a 2 1/2 x 5 tent also, fried some plants like chicken. i think its just enough for a 4x4 tent if used from day one of veg to acclimate the plants to the strength of it. also you could alternate weeks with the 6400k bulb that comes with the housing from htg. the pure uv put a glaze on the pin heatsinks for my cobs also in the smaller tent. and yes @Randomblame is correct, that pure uv bulb will destroy plastic, rubber, and fiber threads in due time. i have all the respect in the world for that bulb, and to think htg/agromax once made a 100% uvb bulb, not a 75%uvb 25% uva like they currently produce. i have always thought of taking the 2ft bulb outside with an extension cord and using it like a wand over the outdoor bushes just for the fun of it to see what happens.
     
  16.  
    Renfro

    Renfro Well-Known Member

    So all this talk of too much UV, if someone happened to have a CMH bulb that has no UV block (has a shit ton of UV) that would be a bad thing, except perhaps for finishing the last week or whatnot? I aks because I have a manufacturer that sent me some bulbs to test.
     
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    mr. childs

    mr. childs Well-Known Member

    cmh is great from the folks i know that have them, but the agromax pure uv will make you respect it instantly
     
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    Renfro

    Renfro Well-Known Member

    Well the bulbs I was sent don't have any UV block incorporated into the manufacture so I don't know how much UVA and UVB they put out, kinda scares me. They are 1000 watt. lol
     
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    mr. childs

    mr. childs Well-Known Member

    de cmh i guess ? 1k, scares me also. i did use an un-shielded cheap chinese 400 mh fish tank bulb years ago & that did pretty well. your grows are so great, please be care if you do choose that agromax bulb, i'd feel guilty if you fried shit.
     
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    Renfro

    Renfro Well-Known Member

    Yeah they are DE CMH.

    Last round I used some 10k DE MH finishing bulbs for the last 14 days, the resin was awesome and the nugs super dense.
     
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