UV Results from the community.

[Rocket Soul]

UVA is bad too
The plants underneath the disco boards are loving it, there's uv 385nm in those but nothing compared to what you'll be using.
I stopped using the 410nm 385nm led as the timer kept playing up and it wouldn't been the first time I was in the room without realising they were on ffs.
My mate has those 4ft Solacure floros in his 8 x 4, I don't think they are on for too long tho, there's a lot of uvb in it.
Maybe look at CLW light fixture or fluence? n see wat their uv ratio is?
I believe you could run those 390nm 400nm for 12 hours on but at what wattage, I don't know

Not a lot of care with uv-a I'd maybe run 5-10% total wattage the entire lights on. Seems to work well for the chilLed boards.

Ill just start at 10w per tray and work myself up. Thx guys

@Moflow btw you had some uva light stress, what did it look like? I know about the serrated edges clawing upwards, anything else? Also, happy you like the disco boards, might pick some up when i tire of Rita...

 

[Otzi]

I am currently testing a 4' Argomax Pure UV along side some HLG550s. I wish I noticed this thread before, I underestimated their power and saw some signs of stress so I had to raise them up a bit. Definitely noticed way more trichomes on the 2 plants I harvested from perpetual clones that I run, even the bottom buds that weren't directly hit by it. Will confirm if the same next harvest

 

[Couch_Lock]

CMH has only a few percent UVA but no UVB, brother. There is no radiation between 275 and 320nm only in the UVA range 320-400nm there is a little spike.

CMH grow lights provide UV (ultra violet) radiation, which although being outside of our range of vision is beneficial (at certain ranges and intensities) to plant growth and development. They produce UV-A, UV-B and UV-C Light, but UV-C is generally very harmful to human eyes. So most high quality manufacturers use a glass filter to block the UV-C output while leaving UV-A and UV-B output intact.

Stick to facts, not conjecture please.

 

[KrazyG]

CMH grow lights provide UV (ultra violet) radiation, which although being outside of our range of vision is beneficial (at certain ranges and intensities) to plant growth and development. They produce UV-A, UV-B and UV-C Light, but UV-C is generally very harmful to human eyes. So most high quality manufacturers use a glass filter to block the UV-C output while leaving UV-A and UV-B output intact.

Stick to facts, not conjecture please.

Facts

 

[Moflow]

UV
The Range



Various CMH bulbs

There appears to be only UV-a in CMH bulbs and not even the full range of UV-a which is
315nm - 400nm .
I can't see any UV-b worth talking about in any of these bulbs above.

 

[Couch_Lock]

Constant UV-B, not 2-3 hour bursts of a reptile bulb is what I want. Phillips 4200k bulbs provide 0.5 constant UV-B.

Plants beyond "hardened up".

its the ppl that buy LED's that are jealous, no uv at all.

buy what ya want, but to say they give off no uv-b is wrong.

 

[mr. childs]

Constant UV-B, not 2-3 hour bursts of a reptile bulb is what I want. Phillips 4200k bulbs provide 0.5 constant UV-B.

Plants beyond "hardened up".

its the ppl that buy LED's that are jealous, no uv at all.

buy what ya want, but to say they give off no uv-b is wrong.

i use the 2ft pure uv bulb in a 4x4 from day one. then quit just before flip, and after flip for the first two weeks alternate between the 660nm red 2ft horti t-5 & the agro 6400k 2ft until week 5. the next three weeks use just the pure uv & blue, last 2 weeks use just the red.

 

[Humple]

Constant UV-B, not 2-3 hour bursts of a reptile bulb is what I want. Phillips 4200k bulbs provide 0.5 constant UV-B.

Plants beyond "hardened up".

its the ppl that buy LED's that are jealous, no uv at all.

buy what ya want, but to say they give off no uv-b is wrong.

As long as we're sticking to facts, would you happen to have a link to the datasheet/test results that show the 4200k bulb's UV-B output?

 

[Couch_Lock]

As long as we're sticking to facts, would you happen to have a link to the datasheet/test results that show the 4200k bulb's UV-B output?

https://www.assets.lighting.philips.com/is/content/PhilipsLighting/fp928034900130-pss-global

https://www.assets.lighting.philips.com/is/content/PhilipsLighting/fp928010001230-pss-global

https://growershouse.com/blog/cmh-315w-lamp-comparison-test-data-review

https://growace.com/blog/ceramic-metal-halide-light-guide-review/

Not spending any more time on this, I'm convinced.

Don't give a shit if ya use purple lights or w/e.

 

[Humple]

2 sec search, are ya that lazy?

https://www.assets.lighting.philips.com/is/content/PhilipsLighting/fp928034900130-pss-global

https://www.assets.lighting.philips.com/is/content/PhilipsLighting/fp928010001230-pss-global

Doesn't look like a 4200k CMH bulb to me.

 

[Couch_Lock]

Doesn't look like a 4200k CMH bulb to me.

Doesn't matter. Top 2 results are Phillips 3100k, there is another link showing 4200k results among the 4.

I own both so IDC.

EVERY website mentions cmh UV output, actually. I doubt many scientists bother to grow cannabis. They can afford all they wanna buy without taking a single risk growing.

Heres another page, I could waste more time if I wasn't working at home today.
https://www.royalqueenseeds.com/blog-the-pros-and-cons-of-using-lec-lights-to-grow-cannabis-n980

 

[Humple]

Doesn't matter. Top 2 results are Phillips 3100k, there is another link showing 4200k results among the 4.

I own both so IDC.

The issue under discussion isn't whether you own them, or whether you should use them, or even if I'm too "lazy" to search out a datasheet for a bulb that isn't remotely related to the conversation. The question is: what are the facts regarding the amount of UV-B in a Phillips 4200k CMH? You mentioned a "0.5 constant" (.5 of what, by the way?) - I presumed this figure must come from some data source, so for the benefit of the people involved in the conversation, I was inquiring after this source. Facts over conjecture, as it were.

 

[Couch_Lock]

I had read it online days ago, somewhere. Its a low percentage for sure but its a constant uv source.

 

[speedyganga]

Hello,

I had read it online days ago, somewhere. Its a low percentage for sure but its a constant uv source.

lol
anyone can read something on the internet, doesn't mean it is true. If you too put it here without checking then your create false infos.

I don't see no UVB neither in the spectra mentioned ...
But there is UVA for sure !

I saw positive difference with 4200K and 3000K CMH compare to HPS but I don't have test on THC to back it up. Just frostier.

 

[deeppep]

using 4x4ft agromax UVA all flowering stage. But actually used couple hours a day from first till third flowering weeks. than from third week starting each day with this uv-a bulbs and it works all day long. now I am close to last 2 weeks. And I would need to put on my Agromax Pure UV bulbs. I have 2x4ft. fixtures in my growspace (10ftx5ft). The only thing I know about it. that I would starting from few minutes a day. and than will add each day one or two minutes more. I will avoid of using it in a day of watering. because plants can be stressed more in a day of watering. And I know, that high concentrate Co2 levels helps plants cooperate with uvb. And I thinking to take off all the big leaves. because leaves will stressed very fast under uvb range. If you guys, have additional info. Or you thinking I`ll make a big mistake, please. let me know... appreciatte any advices) ps. sorry for my broken english(

 

[boostedhonda]

Does anyone have any problems with uvb bulbs stressing plants and causing them to herm out? I have two feminized insane in the membrane from ethos, and they are about three weeks into flower. The larger of the two isthrowing banana pods randomly. All the tops closest to the uv bulb have curled leaves andwhat not. Light is all the way up and I have stopped using the uv. Because of my heightissue, I figured using the pure veg plus uvwouldn’t fry them but I was wrong. I amcontemplating hacking the one that is hermingout but that is the larger of the two and I reallydon’t want to lose the yield but also do t wantseeds. What do u guys think? @Randomblame

 

[Randomblame]

Yepp, too much UV can cause stress and stress can lead to bananas/hermie flowers. Which bulb have you used? Only the pureveg +? What distance and for how long?

Remember the times when the 1st fem seeds came out; they were produced by stressing a fem plant until she hermies and than use the hermie pollen and create a new generation. It works but the plants had a higher hermie tendency.

C. is a so called 2 housing plant which means all fems have also male genetic and under stress almost all fems can create a few male flowers. Today they select a female plant which has almost no hermie tendencies no matter how hard you stress her and then they use collodial silver or gibberelin acids to force the plant to produce male flowers. The seeds created this way are much more stress resistant and in the most cases they are stable. But there are leftovers in todays strains/seeds and if one of the parents is based on such genetic the hermie tendency can again come to light because of recessive genetics. Your strain seems to have this tendency at least one of them...

The best thing you can do currently is to bent the tips into a horizontal position to increase the distance. It's almost stress free and with a higher distance there should be no UV stress. Curled leaves means you have used it with not enough distance. You can also splitt the UV treatments and give them 4x 30 minutes instead of two hours for example. On my first UVB run with 12% reptile bulbs(Arcadia d3 desert) only one plant(a bluedream) has created a few hermie flowers. It was also a lanky strain and has stretched out like crazy and to get it back to the same height I've done the same. I rigorously bent her down until all the shoots were fixed in a horizontal posistion and had the same 12-14" to the light like the other strains in the tent. I've removed as much of the hermie flowers as possible and have collected them for later use.
From this point on she have got no hermie flowers anymore and finished with 4oz dry.

The male flowers were dried and then grinded and shaken through a sieve and with the pollen I've created two fem strains, an Amnesia x Bluedream cross and a GreenPoison x Bluedream. Both are already tested an non of them has shown hermie tendencies and I've used a Agromax PureUV bulb last run and have burned them girls their asses off. 20% loss in yield btw. cause these bulbs are much too strong and their spectrum is much more dangerous cause it starts already between 250 and 275nm and that's UVC! So actually they are not as good as I've thought.

The good news is, dimmable T5 ballasts exsist and you can get them for 110-120vac and 220-240vac.
They need a 1-10v dimmer you can find on alibaba, e3ay or am4zon(10-20$). I've found my Philips HFregulator 224-TL5 220-240 pretty cheap and have got it for 15 bucks. Its a 2x 24w ballast and now I can dimm the pureUV bulbs down until there is no visible stress. Its the only way to use the pureUV bulbs with less the 24" distance. I don't know how much UVB the pureveg+ bulbs have but if you double the distance the problems should dissapear.

 

[boostedhonda]

Yepp, too much UV can cause stress and stress can lead to bananas/hermie flowers. Which bulb have you used? Only the pureveg +? What distance and for how long?

Remember the times when the 1st fem seeds came out; they were produced by stressing a fem plant until she hermies and than use the hermie pollen and create a new generation. It works but the plants had a higher hermie tendency.

C. is a so called 2 housing plant which means all fems have also male genetic and under stress almost all fems can create a few male flowers. Today they select a female plant which has almost no hermie tendencies no matter how hard you stress her and then they use collodial silver or gibberelin acids to force the plant to produce male flowers. The seeds created this way are much more stress resistant and in the most cases they are stable. But there are leftovers in todays strains/seeds and if one of the parents is based on such genetic the hermie tendency can again come to light because of recessive genetics. Your strain seems to have this tendency at least one of them...

The best thing you can do currently is to bent the tips into a horizontal position to increase the distance. It's almost stress free and with a higher distance there should be no UV stress. Curled leaves means you have used it with not enough distance. You can also splitt the UV treatments and give them 4x 30 minutes instead of two hours for example. On my first UVB run with 12% reptile bulbs(Arcadia d3 desert) only one plant(a bluedream) has created a few hermie flowers. It was also a lanky strain and has stretched out like crazy and to get it back to the same height I've done the same. I rigorously bent her down until all the shoots were fixed in a horizontal posistion and had the same 12-14" to the light like the other strains in the tent. I've removed as much of the hermie flowers as possible and have collected them for later use.
From this point on she have got no hermie flowers anymore and finished with 4oz dry.

The male flowers were dried and then grinded and shaken through a sieve and with the pollen I've created two fem strains, an Amnesia x Bluedream cross and a GreenPoison x Bluedream. Both are already tested an non of them has shown hermie tendencies and I've used a Agromax PureUV bulb last run and have burned them girls their asses off. 20% loss in yield btw. cause these bulbs are much too strong and their spectrum is much more dangerous cause it starts already between 250 and 275nm and that's UVC! So actually they are not as good as I've thought.

The good news is, dimmable T5 ballasts exsist and you can get them for 110-120vac and 220-240vac.
They need a 1-10v dimmer you can find on alibaba, e3ay or am4zon(10-20$). I've found my Philips HFregulator 224-TL5 220-240 pretty cheap and have got it for 15 bucks. Its a 2x 24w ballast and now I can dimm the pureUV bulbs down until there is no visible stress. Its the only way to use the pureUV bulbs with less the 24" distance. I don't know how much UVB the pureveg+ bulbs have but if you double the distance the problems should dissapear.

Yea just using the pure veg + uv 4 ft. Had the bulb about 3-4” from the tops hung in the center. Was running for an hour at a time four times a day for about a week. I’m 6’ and the plants were as tall as me so in a 7’ tent I was out of room. Yea I would have loved to have just picked off the nanners and let her keep goings but the more I looked the more I found. So I cut my losses and chopped her found at least 100 nanner pods without much looking. I think your right I think that seed was just predisposed to turning herm.

So now my plan is to just the uv on the side of the plant. I was able to do some finagling with my nets and tilt my light to achieve a more even canopy in relation to the light. Now all my tops are about 8” from the light and I can use the pure uv bulb if I wanted and maintain 24”

 

[Randomblame]

I see no stress in the second row so you need only to bent the higher tops down by 6" or so. Is th

Yea just using the pure veg + uv 4 ft. Had the bulb about 3-4” from the tops hung in the center. Was running for an hour at a time four times a day for about a week. I’m 6’ and the plants were as tall as me so in a 7’ tent I was out of room. Yea I would have loved to have just picked off the nanners and let her keep goings but the more I looked the more I found. So I cut my losses and chopped her found at least 100 nanner pods without much looking. I think your right I think that seed was just predisposed to turning herm.

So now my plan is to just the uv on the side of the plant. I was able to do some finagling with my nets and tilt my light to achieve a more even canopy in relation to the light. Now all my tops are about 8” from the light and I can use the pure uv bulb if I wanted and maintain 24” View attachment 4294079

The pureveg+ have the same spectrum like a 12% reptile bulb and I've used them in 8-12" distance for the whole day without getting issues but I've started lower and with more distance to make them used to it and then I've increased slowly by reducing the distance and run them longer. New bulbs can throw out much more therefor the burn in time is mentioned in the most discriptions. I would mount the bulbs 12" from the tops to make sure they cover a 24" wide and 48" long area evenly. And 12" would be a safe distance and should not cause curled leaf margins or heat stress.

 

[boostedhonda]

I really don’t like to do any training after week 3.... I did some bending in week two but they were already done with their stretch so they didn’t recover as quick as I would have liked. Have u had any experience running the uv bulb on the side of the plant? I would be able to get a much better coverage with the uv from the side as opposed to running it above. @Randomblame