UVB bulbs...

[jawnroot]

Ganja Pasha: I say the following with the best of possible intentions, so don't take it the wrong way. Again, though, I have nearly two decades of experience with bleeding-edge UVB and UVA technology, and the associated biological responses that these wavelengths encourage.

I'm of the opinion that you're oversimplifying the relationship between UVA and biological activity. There's often a tedency to think "Well, if I have X, and I have Y, then Z logically follows." With something as complex as plant functions, which are not close to being totally understood, making logical inductions is not always fruitful (no pun intended). However, testing theories is how we find out new things, and you seem very well read on the subject, so I applaud your experiments.

What you're referring to, the 390nm to 400nm rage, is more near visible than it is UVA. UVA goes down all the way to 315nm, and is broadly defined as 400nm down to 315nm (essentially the beginning of the visible light spectrum, right down to the threshold of UVB).

It's easy to look at spectrum charts, and conclude from them what a lamp will and will not produce. Spectrum charts can be misleading, and I maintain that UVA is produced in adequate levels from most any light source (whereas UVB is not produced in any measurable levels from common light sources) . To emphasize, UV is not used to any large degree for photosynthesis. That's why the PAR charts end at 400nm.

Rather, if UVA does anything at all, it catalyzes reactions that are already taking place. Thus, you do not need the ultra-watts of UV to produce a desired outcome, like you would with standard 400-700 nm light. Indeed, most average UVB emitting bulbs produce only 1 to 2 watts of total UV light.

All this said, I don't want to give the impression that I'm trying to start one of those forum "flame wars." Just a free exchange of ideas. I agree whole-heartedly that there are sources that produce much higher levels of UVA than what you'd find in an incandescent or HPS. Whether that additional UVA will have an impact on smell and taste seems dubious, but I encourage your efforts.

EDIT: The vast majority of UVB emitting bulbs also emit copious amounts of UVA, so as long as you're employing some type of UVB setup, you're guaranteed to get the UVA you want/need.

 

[Guest]

Using the term UV-A for the wavelengths I'm experimenting with is a tad misleading I think, it is perhaps better to consider UV-A as 315 to 380nm and 380 to 410 as 'near UV' or just call it 'violet'.

I'm no biologist and have only the barest grasp of photosynthesis and internal plant mechanisms, but there is a sound scientific basis for my experiments, there is tons of published material out there pertaining to similar experiments with other plants.

I simply cannot agree that most light sources produce UV, fluorescent, HPS and incandescent lamps have glass envelopes and glass blocks UV. I cannot find any spectral graphs that show more than minimal UV output. There are lots of spectral output graphs for all kinds of light sources here:

http://home.att.net/~ledmuseum/spectra.htm

This halogen bulb puts out zero UV:

This Philips 60w soft white incandescent puts out only very low levels of UV:

This HID lamp does put out some UV, but not much:

So no worthwhile sources of UV to be found there, if you can show me an output graph for a fluorescent, HID or incandescent lamp that shows high UV output, I'll be very surprised, unless the lamp has been specifically designed to emit UV, which regular lamps aren't.

Here's the spectral output graph for one of the types of UVA/violet LED I'm using, it is a 390nm LED, I'm also using 380nm, 400nm and 410nm LEDs.

One of the biggest advantages of using LEDs to provide violet light is their narrow emission bandwidth. If using a fluorescent UV emitter, the bandwidth is very large and this means that if differences in taste and smell are discernible in cannabis buds grown with UV from such a source, it would be impossible to know which part of this broad spectrum output is responsible for these differences. However, with LEDs, it is easy to gauge the effects of different parts of the spectrum, hopefully I will be able to determine the effects of the different parts of the spectra in the 380nm to 420nm range as i have LEDs with different output spectras within this range.

 

[knna]

Very good post, jawnroot. I liked very much your second paragraph.

I would like to put in the table a question wich isnt well defined along the thread: where UV range starts. Depending of it, some of the statements done are true or false.

Very often, UV range is simplified and said to start at 400nm. Tecnically it isnt correct, as human eye is able to perceive up to 380nm (specially young people). CIE defines the visible range between 380-780nm. UV is the range below, while IR starts above.

But its true that human sensibility apart of the most used range of 400-700nm is very reduced, thus the often way of using visible range just for that range, wich is too the PAR range. But there is another problem related to this issue, and its plants still photosynthetize at decent figures using light of the 380-400nm range.

The 380-400nm is called the violet range. Tecnically, UltraViolet starts where violet ends, and its at 380nm, not a 400nm (GP, check how most of the SPDs you posted cover the 380-780nm range, and not 400-700nm).

I dont have any special problem calling the violet as UV always we understand its a simplification. But it has been defined in the thread, please when talk about UV specify for what range are you talking exactly, as it does huge differences.

Pure UVA, below 380nm, dont have any ability to promote photosynthesis on higher plants species, although it plays significant roles on other biological processes. I believe its correct it enhances terpenes production, but it something still to be proven on cannabis, specially if its a constant or just temporary response.

BTW, im with anybody trying to learn more about our plant. I dont mind if their insights are correct or no, kudos for all

 

[knna]

Ouch! GP and me were adressing the same topic at same time.

Im with you on the advantage of experimenting with narrow bands, but it too is far harder to experiment. More versatil, but more time needed to take conclusions from the experiments.

 

[jawnroot]

GP: Again, spectrum charts can be misleading. The "very low levels" you refer to are more than adequate to catalyze the biological processes you're trying to encourage, at least with the data we currently have available.

But then, we're just a bunch of arm-chair experts here, swapping theories. Let us know how the UVA experiment works out.

 

[gramsci.antonio]

So no worthwhile sources of UV to be found there, if you can show me an output graph for a fluorescent, HID or incandescent lamp that shows high UV output, I'll be very surprised, unless the lamp has been specifically designed to emit UV, which regular lamps aren't.

what you think of this?

http://advancedtechlighting.com/cdmed18.htm

 

[gramsci.antonio]

I would like to put in the table a question wich isnt well defined along the thread: where UV range starts. Depending of it, some of the statements done are true or false.

Sorry knna, i thought this was clear for everybody: the definition of UV rely on the capability of a wavelength of ionizing a piece of a certain metal (or a mix of some metals).

UVB (315-280 nm) are the kind of UV we're looking for, because the triggers we are looking to activate, answer just to those frequencies.

 

[gramsci.antonio]

I have been reading a lot about this CMH mullarky recently and I must say I'm VERY interested in trying it out!

In fact, it'll most likely be my next side-by-side grow. Have you tried CMH yet?

Yeah i have a CMH, and i grow with it from seed to bud.

But i've never grown with an HID, so prefer to not give any comment about the differencies, since they may be misleading.

 

[blazeoneup]

I have been using uvb floresents for a while now, I buy the 24" floresent fixtures and then cut bend and paint reflectors to direct the lighting towards the plants and mount them to my 1000w hoods, I put one 24" 20 watt repti glo 10.0 uvb bulbs on each side of the 1k hoods. The bulbs have a rating of 33% uva and 10% uvb these work fine for me thats 40watts per 1k.

Here are some pictures of what I use and how I do it. Just sharing my method for using them. I do not run the uvb lighting during veg, Only in flower once the buds begin developing. I have them plugged into a surge protector and the surge protector hooked to a timer. I run run them 8 hrs a day from week 3 flower up to 2 weeks from harvest. So around 6 weeks of uvb lighting. The uvb lights kick on 2hrs after lights on and kick off 2 hrs before lights off.

Here are some pictures. Of a room Im currently getting started I have 3 of the hoods finished and 1 to go. Now for the pics.

 

[gramsci.antonio]

noted any improvment?

 

[blazeoneup]

Lets put it this way. I try new things, When they work I implement that into my future grows. This being a new room, If it didnt work or show any differences I wouldnt waste 500$ on setting up uvb lighting. Some quick math.

Roll of metal for the reflectors, 50$, 12$ per 24" fixture 12x8=96$ 2 spray cans of primer 2 cans gloss white paint 16$ total, 8 repti glo 10.0 uvb bulbs 28$ each 28x8=224$ 8 16 gauge grounded electrical cords 5$ per 8x5=35$ and also 4 16 gauge extension cords 6$ per 24$ total. 224+96=50+16+35+24= right around 450$. Im not one to blow money, Basically all together it cost right around 500$ to implement uvb into this 4k room. If it didn't work what a waste of 500$

 

[Nifty]

a

 

[DIGITALHIPPY]

Lets put it this way. I try new things, When they work I implement that into my future grows. This being a new room, If it didnt work or show any differences I wouldnt waste 500$ on setting up uvb lighting. Some quick math.

Roll of metal for the reflectors, 50$, 12$ per 24" fixture 12x8=96$ 2 spray cans of primer 2 cans gloss white paint 16$ total, 8 repti glo 10.0 uvb bulbs 28$ each 28x8=224$ 8 16 gauge grounded electrical cords 5$ per 8x5=35$ and also 4 16 gauge extension cords 6$ per 24$ total. 224+96=50+16+35+24= right around 450$. Im not one to blow money, Basically all together it cost right around 500$ to implement uvb into this 4k room. If it didn't work what a waste of 500$

shit man i give you hella props for the clean-ass light setup you made....
running in that 4K range myself i know that 450$ is nothing..i shit 100$'s into this thing so whats another 450... but i also look at it like an investment, and its a one time cost for a long term of benefit.

you could have probably done it cheaper but it wouldnt look/work so well, i bet its a sinch to turn all thoes lights on and off. i apreciate how everythig is modular and plug/unplug-able.
DH

 

[jawnroot]

Lets put it this way. I try new things, When they work I implement that into my future grows. This being a new room, If it didnt work or show any differences I wouldnt waste 500$ on setting up uvb lighting. Some quick math.

Roll of metal for the reflectors, 50$, 12$ per 24" fixture 12x8=96$ 2 spray cans of primer 2 cans gloss white paint 16$ total, 8 repti glo 10.0 uvb bulbs 28$ each 28x8=224$ 8 16 gauge grounded electrical cords 5$ per 8x5=35$ and also 4 16 gauge extension cords 6$ per 24$ total. 224+96=50+16+35+24= right around 450$. Im not one to blow money, Basically all together it cost right around 500$ to implement uvb into this 4k room. If it didn't work what a waste of 500$

Or, you can spend approximately $225 on three MegaRay's ($450 on six if you really wanted to cover that whole area), and get far better UV penetration and coverage. With the distance that you have to mount the 1000 watter above the plants, they're getting nil UV, as the 10.0 loses all of its effectiveness after 10 inches. Essentially, if your plants are getting any UV at all, it would be the top inch or so. Plus, with the way you have the tubes mounted, plants directly under the 1000 wouldn't be getting UV even if the fixture was right on top of them (ie: what UV you are producing is going off to the sides). One needs, at minimum, 50 microwatts/cm2 to have an impact, and after 10 inches the 10.0 is not producing that.

If it's not too late to return that equipment, I'd highly recommend getting your money back and investing in some MegaRay's, if you really want to see what UV is capable of. Tubes are not a very good option for full sized grows like that, as they'll have minimal impact, if anything at all. Tubes are only good if you can mount them within 2 inches of plant surfaces. They're not all that different from visible-light tubes, in the sense that all the usable energy is concentrated within 6 inches of the bulb, and has the most effectiveness at 4 inches and under.

A MegaRay, by contrast, is an externally ballasted HID light, specifically designed to produce about 225 microwatts/cm2 of UV at 12." Another option is the Arcadia D3 7% compact fluorescent. Although it doesn't have near the penetration of the megaray, you could mount a few Arcadia's around the plants vertically, and probably get the same coverage as the MegaRay, for similar or less money. The Arcadia is sold by only one retailer in America, drsfostersmith (just put www. in the front and .com on the end).

I should note that most other HID and compact UVs are dangerous, were not designed for living organisms, and should be avoided (even ones that claim to be for reptile use). Also, avoid the self ballasted mercury vapor UV bulbs, as they produce an excess of heat (which they were designed to do).

UV lighting is a tricky cat to tame.

 

[blazeoneup]

Or, you can spend approximately $225 on three MegaRay's ($450 on six if you really wanted to cover that whole area), and get far better UV penetration and coverage. With the distance that you have to mount the 1000 watter above the plants, they're getting nil UV, as the 10.0 loses all of its effectiveness after 10 inches. Essentially, if your plants are getting any UV at all, it would be the top inch or so. Plus, with the way you have the tubes mounted, plants directly under the 1000 wouldn't be getting UV even if the fixture was right on top of them (ie: what UV you are producing is going off to the sides). One needs, at minimum, 50 microwatts/cm2 to have an impact, and after 10 inches the 10.0 is not producing that.

If it's not too late to return that equipment, I'd highly recommend getting your money back and investing in some MegaRay's, if you really want to see what UV is capable of. Tubes are not a very good option for full sized grows like that, as they'll have minimal impact, if anything at all. Tubes are only good if you can mount them within 2 inches of plant surfaces. They're not all that different from visible-light tubes, in the sense that all the usable energy is concentrated within 6 inches of the bulb, and has the most effectiveness at 4 inches and under.

A MegaRay, by contrast, is an externally ballasted HID light, specifically designed to produce about 225 microwatts/cm2 of UV at 12." Another option is the Arcadia D3 7% compact fluorescent. Although it doesn't have near the penetration of the megaray, you could mount a few Arcadia's around the plants vertically, and probably get the same coverage as the MegaRay, for similar or less money. The Arcadia is sold by only one retailer in America, drsfostersmith (just put www. in the front and .com on the end).

I should note that most other HID and compact UVs are dangerous, were not designed for living organisms, and should be avoided (even ones that claim to be for reptile use). Also, avoid the self ballasted mercury vapor UV bulbs, as they produce an excess of heat (which they were designed to do).

UV lighting is a tricky cat to tame.

First let me thank you for your responce. I do disagree with you in a sense. I will have to admit the megarays are a better bang for the buck. I will also admit they have better penetration also.


I would have to disagree with you on your 10" statement. For one I have 3 good friends who actually raise reptiles. One of them uses the exact same bulbs for there 40 gallon reptile tank 2 20w bulbs and the tank is around around 18-20" in hieght. The lights are mounted simular to a fishtank but with screen over top the tank and under the lights set on the tank.

Now if these lights only penetrate a whopping 10" that would mean the Iguana in his 40 gallon tank wouldn't have close to effecient lighting. But he has been using these lights for atleast 2 years I know of and his iguana is still healthy and growing!

So I have to think if they can keep an iguana alive and well from 18-20" away they will certainly penetrate further than 2-3" into the canopy. With these nice new aircooled hoods, I will be able to get the lights within 8-10" of the plants. So all the tops will get enough. I looked into the mega rays I almost purchased them but hell I didn't need to. I have used this same type of rig up previously I was able to notice the differences in more then just one crop.

Heres a quote.

High output fluorescent reptile lights boasts the most concentrated UVB spectrum available. Aids in Vitamin D3 synthesis and calcium absorption. Emits 10% UVB and up to 33% UVA; outputs activate UVB up to 20" from the bulb's surface!

And I have to agree with the above quote, Simply because its working for an iguana in a tank thats around 20" in hieght.

Have you ever put a uvb light 2" from a plants tissue? I have and let me tell you all it takes is 8-10 hrs of that for a plants leaf tissue to begin to dry out and leafs start rolling. Your not trying to give the plants a sunburn, Your simply trying to stimulate them.

 

[Guest]

I suppose I should clarify that I'm not actually using UV in my experiment, I'm using violet in the 380 to 420nm range. I'm aiming to investigate it's effects on terpenoids and therefore the smells and tastes of my plants and end product. Also, given that terpenoids also effect the nature of the effects of THC then there may be worthwhile changes in the nature of the effect of a given plant subjected to violet light.

After I have completed these experiments, I will move on to experimenting with UV-B in the 290-320nm range and see if it promotes great resin production and potency. I know there are those like blazeoneup that say it does, but I haven't seen any proper experiments or comparisons between plants grown with UV-B and those grown without.

I understand that many folks are raving about their CMH, but to me, using one of those is a step backwards, not forwards, I've switched to LEDs and won't be using HID lighting again I think. Shame that UV-B LEDs are so damn expensive currently, but hopefully that will change.

 

[jawnroot]

Blaze, note that the above quote says it "emits UV up to 20 inches from the bulb's surface." Sure, I buy that. But guess how much UV it's emitting at 20"? About 5 microwatts/cm2 (ie: next to nothing, and certainly not enough to impact D3 production, let alone prompt physiological reactions in your plants). I can show you charts regarding the penetration of the Exoterra, if you'd like.

Plants can use anywhere from 225 microwatts/cm2 down to 50 microwatts/cm2 of UVB. With the Reptisun 5.0, the plants can almost touch the bulb and have no negative effects. With the 10.0, you want them a minimum of 1.5 inches away.

I can almost guarantee you that the leaf roll you experienced was due to the heat (infrared) emitted from the tube, not the UV (unless they were closer than 1.5 inches, in which case UV could very well have had an impact). It could have resulted from other factors as well, beyond the bulb.

If the 150ish microwatts/cm2 of UV coming from the 10.0 at 2 inches is enough to fry plants, they would not be able to survive in the desert environment from which they originate (ie: 225 microwatts/cm2 of UV for most of the day).

As I said, I have 20 years experience in the field (UV lighting). You can either take my advice, or ignore it. I'm not trying to push you one way or the other, and you're welcome to run the UV lights you have, but I can 100% guarantee you they will have zero impact on the plants.

 

[DIGITALHIPPY]

Blaze, note that the above quote says it "emits UV up to 20 inches from the bulb's surface." Sure, I buy that. But guess how much UV it's emitting at 20"? About 5 microwatts/cm2 (ie: next to nothing, and certainly not enough to impact D3 production, let alone prompt physiological reactions in your plants). I can show you charts regarding the penetration of the Exoterra, if you'd like.

Plants can use anywhere from 225 microwatts/cm2 down to 50 microwatts/cm2 of UVB. With the Reptisun 5.0, the plants can almost touch the bulb and have no negative effects. With the 10.0, you want them a minimum of 1.5 inches away.

I can almost guarantee you that the leaf roll you experienced was due to the heat (infrared) emitted from the tube, not the UV (unless they were closer than 1.5 inches, in which case UV could very well have had an impact). It could have resulted from other factors as well, beyond the bulb.

If the 150ish microwatts/cm2 of UV coming from the 10.0 at 2 inches is enough to fry plants, they would not be able to survive in the desert environment from which they originate (ie: 225 microwatts/cm2 of UV for most of the day).

As I said, I have 20 years experience in the field (UV lighting). You can either take my advice, or ignore it. I'm not trying to push you one way or the other, and you're welcome to run the UV lights you have, but I can 100% guarantee you they will have zero impact on the plants.

how do you know his hoods arnt a foot from the canopy?
what do you do if u dont mind me ask, to work with uvb for so many years.

ive always known uvb was short, but how does the suns uvb get all the way to the planet?

i usualy hang my uvb at 12-18 inch.


some info i found a while ago supports what everyone is saying.

Remember that UV light cannot penetrate glass, so when overhead UVB light sources are used, the top of the enclosure must be a wire mesh that is not too fine. It is recommended that the UVB light source should be less than 18 inches from where the Bearded Dragon spends most of its time; 10-12 inches is optimal.

http://animal.discovery.com/guides/reptiles/iguanas/beardeddragon_03.html

 

[blazeoneup]

Blaze, note that the above quote says it "emits UV up to 20 inches from the bulb's surface." Sure, I buy that. But guess how much UV it's emitting at 20"? About 5 microwatts/cm2 (ie: next to nothing, and certainly not enough to impact D3 production, let alone prompt physiological reactions in your plants). I can show you charts regarding the penetration of the Exoterra, if you'd like.

Plants can use anywhere from 225 microwatts/cm2 down to 50 microwatts/cm2 of UVB. With the Reptisun 5.0, the plants can almost touch the bulb and have no negative effects. With the 10.0, you want them a minimum of 1.5 inches away.

I can almost guarantee you that the leaf roll you experienced was due to the heat (infrared) emitted from the tube, not the UV (unless they were closer than 1.5 inches, in which case UV could very well have had an impact). It could have resulted from other factors as well, beyond the bulb.

If the 150ish microwatts/cm2 of UV coming from the 10.0 at 2 inches is enough to fry plants, they would not be able to survive in the desert environment from which they originate (ie: 225 microwatts/cm2 of UV for most of the day).

As I said, I have 20 years experience in the field (UV lighting). You can either take my advice, or ignore it. I'm not trying to push you one way or the other, and you're welcome to run the UV lights you have, but I can 100% guarantee you they will have zero impact on the plants.

Some of what you say makes sense. But I can garuntee your no impact theory is far off base from reality. There is a reason why the lights will hang from pully's and there's a reason why those are nice air cooled hoods. The reasons for these. I will be able to keep the lights 8-10" away from the plants canopy steady. So if you still think that these lights are not effective from 8-10" well all I can say is try it once.


I have done my own experimenting with uvb bulbs. So when I say puttig a uvb bulbs within 2" from the plants caused leaf rolling I can say that without a doubt. Its like this if you have a room which your running 30 plants for example and you've added a uvb floresent onto a single plant out of the 30 plants. Then overnight you have one plant close to the uvb and it has leaf tips cupping/rolling and you have 29 other plants that look perfectly normal well its easy to assume the cupping/rolling come from the uvb light. Whether it be heat or uvb. If I can put my arm 2" from a uvb floresent and in less then 10 minutes notice my skin is burning it will surely burn leaf tissues

I'm not trying to argue with you or anything just stating facts from my own personal experience.

 

[DEVIL OG]

Thank you very much , I believe you answered all the questions I had.
Thanks guineapig and the rest of yall.

Nothanks to anyone hating..