Uv = Blacklight?

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StonedBlue

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I see ads for uv blacklights. Are these any good for supplemental lighting or is it a different light to get uv?
Also is there a formula or something to determine the amount needed?
 
Aqua Man

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If you are looking for UV I would stick with what has been shown to work. I believe its about 5-10% of light source being UV is what seems to be agreed upon. Reptile bulbs are commonly used. @GT21 I think uses them and could probably help you out
 
CrimsonEcho

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I see ads for uv blacklights. Are these any good for supplemental lighting or is it a different light to get uv?
Also is there a formula or something to determine the amount needed?
If the uv blacklights you are talking about are the ones for parties, they emit between 380nm to 390nm i think. When they say add uv people talk about uvb which is 280-315nm. No idea about the amount tho. As far as i know people use reptile bulbs with special uvb output and don’t run them continuously.
 
GT21

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If the uv blacklights you are talking about are the ones for parties, they emit between 380nm to 390nm i think. When they say add uv people talk about uvb which is 280-315nm. No idea about the amount tho. As far as i know people use reptile bulbs with special uvb output and don’t run them continuously.
I use them through the whole light cycle from right after stretch to chop.
 
StonedBlue

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Suggestions on where to obtain one? My led has 2uv bulbs on the fixture itself. But I need more, especially for my hps area
 
StonedBlue

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I've used I for 3 or 4 years. But only the last 3 weeks because replacement lamps are expensive for my fixture. (built into the led fixture. My hps hasn't been getting any.
 
StonedBlue

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Ok, I've found the right ones. Any input on how far away to use? Amount?
For reference, my led fixture had 2 bulbs totaling 30w for a 3.5 x 3.5 foot area. But I'll bet they were guessing. I've found recommendations to only use last 2 or 3 weeks.or the whole time. Or all the time except the last 2 weeks.seems like the last weeks would be most beneficial.
Btw, thank you everyone for replying.
The Farm Rocks
 
GT21

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Ok, I've found the right ones. Any input on how far away to use? Amount?
For reference, my led fixture had 2 bulbs totaling 30w for a 3.5 x 3.5 foot area. But I'll bet they were guessing. I've found recommendations to only use last 2 or 3 weeks.or the whole time. Or all the time except the last 2 weeks.seems like the last weeks would be most beneficial.
Btw, thank you everyone for replying.
The Farm Rocks
When does the sun have uv? First 2 weeks? Maybe week 4-5?

No..its all the time.

You use them after stretch because i am lazy and dont want to move the bulbs everyday while theyre stretching.
 
Toaster79

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Ok, I've found the right ones. Any input on how far away to use? Amount?
For reference, my led fixture had 2 bulbs totaling 30w for a 3.5 x 3.5 foot area. But I'll bet they were guessing. I've found recommendations to only use last 2 or 3 weeks.or the whole time. Or all the time except the last 2 weeks.seems like the last weeks would be most beneficial.
Btw, thank you everyone for replying.
The Farm Rocks


Like I said, i used mine seed to harvest. Might utilize it again.
 
Aqua Man

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If you wanna get all scientific about it. Use a loop to inspect your trichs. If they are leaning over or appear to be damaged (prematurely ambering) then raise the UV a bit but you would want to check first thing in the morning and not at night after a full cycle of lights. You can make it as complicated as you want but its a lot less work to get the same equipment and use someone else's findings. Especially to get ya in the ballpark. IMO with no experience it would make sense to me that the UV light intensity is far more important then when or how long you run it and the more you can provide without causing irreversible damage the better. I think this has been shown as approx. 5-10% of total wattage in UV spectrum. The UV bulbs are typically 40% UV light, 10%UVB and 30% UVA. So if you have 500 watts of light with no other UV source (CMH,MH,HPS and most LED all provide some UV). 500w/10 is 50W. But that 50watts is only 40% UV so 50W-100watts would pretty much put you in the range of what has been shown to be effective. Add to that the distance with 2 differing light sources the difference in distance will change the spread and intensity.

You see you can make it as complicated as you want but is it really necessary and for how much gain? IMHO I would just stick with what GT21 said in terms of amount and height based on real experience and I think the duration of use is of far less significance. But again I have 0 experience using it and just going of studies and science.
 
StonedBlue

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Reading bunch of articles it doesn't seem like anyone knows much. The 30 watts I've got was built into my fixture. (California lightworks) they say run thru last 3 weeks but I've always run whole flowering cycle. Just has no idea if that was right. My thought was that at the height of summer we get more uv than spring or fall. Was worried that uv might signal plant it is summer rather than closing in on harvest time.
I just hate using methods I don't understand.
I appreciate everyone's input and expieience. I'm going to go with 10% of total light the whole flower. When my flower rooms are finished I think I'll expirement.
 
CrimsonEcho

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Reading bunch of articles it doesn't seem like anyone knows much. The 30 watts I've got was built into my fixture. (California lightworks) they say run thru last 3 weeks but I've always run whole flowering cycle. Just has no idea if that was right. My thought was that at the height of summer we get more uv than spring or fall. Was worried that uv might signal plant it is summer rather than closing in on harvest time.
I just hate using methods I don't understand.
I appreciate everyone's input and expieience. I'm going to go with 10% of total light the whole flower. When my flower rooms are finished I think I'll expirement.
I don’t think it will signal the plant that it is summer and delay the ripening, if that was the case some mountain indicas would never ripen, some get much more uv in their native habitat.
Just too much uvb can damage your plants, its what gives us sunburn and does the same for plants.
When i was looking into it, i noticed the lack of documentation about this whole uvb thing too but, GT21 and Toaster79 has personal experience so i think you will be good if you follow them.
 
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