so we're talking different types of uv...
-
ICMag with help from Landrace Warden and The Vault is running a NEW contest in November! You can check it here. Prizes are seeds & forum premium access. Come join in!
UVB bulbs...
- Thread starter dontstepongrass
- Start date
dontstepongrass said:
Yes. UVR is filtered as it passes through the atmosphere. First UVC is filtered by the ozone and the further the distance to the surface of the earth the weaker the intensity of what is left, namely UVA and UVB. Even though either can still burn skin, UVA doesn't penetrate like UVB does. Which is why, if one implements UV into their grow, they should have a safety procedure in place. i.e. Only work in the grow room while the UV is timed-off or can be remotely shut off upon entering, less because of short term effects than long term ones.
Namaste, mess
Last edited:
Reading here Mel Frank & Ed Rosenthal Growers Guide and it says:
Small quantities of cannabinoids are present in the internal tissues of the plant. The bulk is found in small single cells (non-articulated laticifers) that elongate to form small, individual resin canals. The resin canals ramify the developing shoots, and penetrate the plant's conducting tissue (phloem). Minute clumps of resin found in the phloem are probably deposited by these resin canals. Other plant cells contain insignificant amounts of cannabinoids and probably a good 90 percent of the cannabinoids are localised in the resin
glands.
Small quantities of cannabinoids are present in the internal tissues of the plant. The bulk is found in small single cells (non-articulated laticifers) that elongate to form small, individual resin canals. The resin canals ramify the developing shoots, and penetrate the plant's conducting tissue (phloem). Minute clumps of resin found in the phloem are probably deposited by these resin canals. Other plant cells contain insignificant amounts of cannabinoids and probably a good 90 percent of the cannabinoids are localised in the resin
glands.
N
Nifty
a
Last edited:
thank you nifty!
glad to hear you did an actual side by side. way to go!
glad to hear you did an actual side by side. way to go!
N
Nifty
a
Nifty any answer as long as it's honest is great!
It's interesting how opinions differ. Differences in perception play a big role.
Some people say more blue light, hence MH, will make a difference in taste/resin versus HPS. I don't have an opinion on that, really. I use CFL's for veg and I mark a difference easy of growth, so to say, leaf colour and my hydro bill but I am not sure if it smells any different or richer, defenately not a huge difference if any.
It's interesting how opinions differ. Differences in perception play a big role.
Some people say more blue light, hence MH, will make a difference in taste/resin versus HPS. I don't have an opinion on that, really. I use CFL's for veg and I mark a difference easy of growth, so to say, leaf colour and my hydro bill but I am not sure if it smells any different or richer, defenately not a huge difference if any.
N
Nifty
a
wow 300 W is a shitload of energy.... sure it's really worth the effort?
N
Nifty
a
Nifty said:At about 20-30 inches the intensity is similar to temperate region outdoor UVB intensity over most of the grow-space lit by a 600w hps.
You could reduce down the number of hours of use per day if you want to keep energy useage low.
Yeah, for me, it's worth it for the increase in quality!
never thought about using a CMH?
N
Nifty
a
jawnroot
Member
Hello all. I felt I could offer something meaningful to this thread, so I'm going to devote my first post to it.
At the outset, I'm not going to make a claim one way or another about UVB and it's impact on resin production, etc. The jury is still out on that as far as I'm concerned.
That aside, I have years of experience keeping exotic reptiles, and know just about everything there is to know about UVB bulbs and lamps. One thing you need to be aware of is that there are good UVB sources, poor ones, and dangerous ones.
Let's start off with the good ones. If you have a normal sized grow, get the MegaRay externally ballasted (EB) 60 watt (ReptileUV sells them, do a google for it). It produces the best and safest UVB spectrum out there, in the best possible footprint, and emits a minimal amount of heat. It also has the penetration power a full-sized plant needs. Similar to how visible-light fluorescent tubes won't give you the penetration you require for a full sized grow, UV tubes will not give you what you're looking for in a plant that's over 12", unless you run them vertically (which is cost prohibitive, given the number of them you'd need). Even the best fluorescent tube (Reptisun 10.0) will only penetrate down to about 8" maximum, after which the UV output is not enough to have an impact.
Now, that said, there are instances where a fluorescent UV tube would come in handy, specifically for smaller or micro grows. In this case, there are only two real options: the Reptisun 5.0 and the Reptisun 10.0. All the rest of the tubes out there are either ineffective, dangerous, or both (avoid at all costs any T5 UV tube). The Reptisun 5.0 is great because it provides adequate levels of UV when mounted within 4" of the plant surfaces, AND is also a 5500K 93CRI light producing bulb. In other words, if you mount a few of these close to your plants, you're getting UV and supplemental light.
The 5.0's go for about $14 each, which is no more than you'd pay for a full spectrum fluoro tube, so it's a win-win. Another advantage of the 5.0 is that your plants can practically touch the bulb and not get hazardous levels of UV. In fact, the heat from the bulb would damage the plants before excessive UV becomes an issue (which it wouldn't with this bulb anyhow).
The Reptisun 10.0 is also a safe and effective choice, and it puts out about twice the amount of UV as the 5.0. The only downside is that the visible light they do produce is not very usable by plants. Also, one needs to keep these at minimum 1.5" away from plants, or you risk UV damage.
Remember, more is not better. You only want 225 microwatts/cm2 absolute maximum (50 microwatts/cm2 min), and you need to make sure that wattage is emitted in a safe/natural spectrum (290-320 nm...more on this further down).
As mentioned earlier, there are a lot of BAD choices as far as UVB bulbs go. The ones classified as dangerous would be the Reptisun 5.0 and 10.0 compact fluorescent bulbs (not the tubes), and any T5 tube. Also, the professional bulbs by Osram and others are equally dangerous. The reasons for this are manifold, but in short: either these bulbs produce too much UVB, the UV is in a dangerous spectrum, or both. Many bulbs marketed as UVB bulbs produce radiation below 290nm (far below in some cases). Below 290nm, and you get into the realm of UV that can damage genetics, and cause other, more immediate concerns (burning the plant, etc). Whereas UVB above 290nm is safe (ie: no more dangerous than afternoon sun), below 290nm is where all the fear associated with UV rays comes from.
I could write on and on and on about this topic, and still not cover everything. The basic summary is this: If you have a large area to light, use a MegaRay 60 watt EB (NOT the SB 100 watt or 160 watt), and follow the spectrum chart that comes with the bulb to get the UV coverage you're looking for. The MegaRay was designed around living organisms from the ground up; there is no better UV bulb for biological work at this point in time. If you have a small grow, or don't mind running many vertical fluorescent fixtures, look into the Reptisun 5.0 or 10.0, depending upon the output you desire. They are just as safe and effective as the MegaRay, but don't put out nearly as much UV, and thus require closer mounting/more bulbs to cover the same area.
At the outset, I'm not going to make a claim one way or another about UVB and it's impact on resin production, etc. The jury is still out on that as far as I'm concerned.
That aside, I have years of experience keeping exotic reptiles, and know just about everything there is to know about UVB bulbs and lamps. One thing you need to be aware of is that there are good UVB sources, poor ones, and dangerous ones.
Let's start off with the good ones. If you have a normal sized grow, get the MegaRay externally ballasted (EB) 60 watt (ReptileUV sells them, do a google for it). It produces the best and safest UVB spectrum out there, in the best possible footprint, and emits a minimal amount of heat. It also has the penetration power a full-sized plant needs. Similar to how visible-light fluorescent tubes won't give you the penetration you require for a full sized grow, UV tubes will not give you what you're looking for in a plant that's over 12", unless you run them vertically (which is cost prohibitive, given the number of them you'd need). Even the best fluorescent tube (Reptisun 10.0) will only penetrate down to about 8" maximum, after which the UV output is not enough to have an impact.
Now, that said, there are instances where a fluorescent UV tube would come in handy, specifically for smaller or micro grows. In this case, there are only two real options: the Reptisun 5.0 and the Reptisun 10.0. All the rest of the tubes out there are either ineffective, dangerous, or both (avoid at all costs any T5 UV tube). The Reptisun 5.0 is great because it provides adequate levels of UV when mounted within 4" of the plant surfaces, AND is also a 5500K 93CRI light producing bulb. In other words, if you mount a few of these close to your plants, you're getting UV and supplemental light.
The 5.0's go for about $14 each, which is no more than you'd pay for a full spectrum fluoro tube, so it's a win-win. Another advantage of the 5.0 is that your plants can practically touch the bulb and not get hazardous levels of UV. In fact, the heat from the bulb would damage the plants before excessive UV becomes an issue (which it wouldn't with this bulb anyhow).
The Reptisun 10.0 is also a safe and effective choice, and it puts out about twice the amount of UV as the 5.0. The only downside is that the visible light they do produce is not very usable by plants. Also, one needs to keep these at minimum 1.5" away from plants, or you risk UV damage.
Remember, more is not better. You only want 225 microwatts/cm2 absolute maximum (50 microwatts/cm2 min), and you need to make sure that wattage is emitted in a safe/natural spectrum (290-320 nm...more on this further down).
As mentioned earlier, there are a lot of BAD choices as far as UVB bulbs go. The ones classified as dangerous would be the Reptisun 5.0 and 10.0 compact fluorescent bulbs (not the tubes), and any T5 tube. Also, the professional bulbs by Osram and others are equally dangerous. The reasons for this are manifold, but in short: either these bulbs produce too much UVB, the UV is in a dangerous spectrum, or both. Many bulbs marketed as UVB bulbs produce radiation below 290nm (far below in some cases). Below 290nm, and you get into the realm of UV that can damage genetics, and cause other, more immediate concerns (burning the plant, etc). Whereas UVB above 290nm is safe (ie: no more dangerous than afternoon sun), below 290nm is where all the fear associated with UV rays comes from.
I could write on and on and on about this topic, and still not cover everything. The basic summary is this: If you have a large area to light, use a MegaRay 60 watt EB (NOT the SB 100 watt or 160 watt), and follow the spectrum chart that comes with the bulb to get the UV coverage you're looking for. The MegaRay was designed around living organisms from the ground up; there is no better UV bulb for biological work at this point in time. If you have a small grow, or don't mind running many vertical fluorescent fixtures, look into the Reptisun 5.0 or 10.0, depending upon the output you desire. They are just as safe and effective as the MegaRay, but don't put out nearly as much UV, and thus require closer mounting/more bulbs to cover the same area.
Last edited:
G
Guest
Excellent info jawnroot.
I think there are two effects of UV that need to be explored - the effect of 310-320nm UV-B on trichome production and potency and the effects of 380-410nm UV-A on taste and smell.
I'm experimenting with 380-410nm UV-A light using LEDs, only just getting started, but I will post my results eventually.
I think there are two effects of UV that need to be explored - the effect of 310-320nm UV-B on trichome production and potency and the effects of 380-410nm UV-A on taste and smell.
I'm experimenting with 380-410nm UV-A light using LEDs, only just getting started, but I will post my results eventually.
jawnroot
Member
The UVA you're referring to is near visible light. Any bulb, from an incandescent house light, to your HPS flowering light, produces UVA in adequate quantities. I doubt it has the energy required to impact taste and smell (that's probably influenced more by UVB, and even more by genetics).
Last edited:
G
Guest
Er no, incandescent and HPS lighting produces very very little UVA.
White fluorescents don't either:
Metal Halides have some output in the UV spectrum:
Mercury Vapour lights however do put out a decent amount of UV-A:
If we consult some photosynthetic spectral charts, we can see that UV-A light around 400nm has a strong effect on Chlorophyll A and a lesser (but still significant) effect on carotenoids and a small effect on Chlorophyll B.
From the above graph, it is clear that light in the violet-blue part of the spectra (390-440nm) has a strong effect on carotenoids so it is reasonable to assume that increased levels of violet-blue light during flowering will increase taste and smell as it is the carotenoid terpenoids that are largely responsible for the smells and tastes.
Now, there are various terpenoids in cannabis, and until someone publishes detailed spectral data for these specific terpenoids, we do not know at what precise wavelengths they have peak response. Here is a chart for various carotenoid-terpenoids found in plants like soy and marigolds, it gives you some idea of the kind of data we need for cannabis, then we can provide the precise spectra cannabis requires for peak terpenoid production.
I hope that makes things a little clearer on the UV-A/violet to increase taste and smell theory that I intend to explore. I am going to flower a set of clones without any added UV/violet/blue light then flower another set of identical clones with added UV/violet/blue light and see if there is any change in the taste and smell, it is also possible that the nature of the psychoactive effects could be altered as terpenoids also affect the nature of the effects of cannabis.
I love trippy, psychedelic effects, and it is maybe the case that there are certain terpenoids that work in conjunction with THC and other substances to create these trippy effects, if this 'trippy terpenoid' can be identified and the peak wavelength determined, then I could use LEDs to provide lots of light at this particular wavelength and increase the trippy nature of the effects. There is a lack of readily available information on this subject, given the illegal nature of cannabis across most of the globe, there is very little scientific study being done on this subject.
White fluorescents don't either:
Metal Halides have some output in the UV spectrum:
Mercury Vapour lights however do put out a decent amount of UV-A:
If we consult some photosynthetic spectral charts, we can see that UV-A light around 400nm has a strong effect on Chlorophyll A and a lesser (but still significant) effect on carotenoids and a small effect on Chlorophyll B.
From the above graph, it is clear that light in the violet-blue part of the spectra (390-440nm) has a strong effect on carotenoids so it is reasonable to assume that increased levels of violet-blue light during flowering will increase taste and smell as it is the carotenoid terpenoids that are largely responsible for the smells and tastes.
Now, there are various terpenoids in cannabis, and until someone publishes detailed spectral data for these specific terpenoids, we do not know at what precise wavelengths they have peak response. Here is a chart for various carotenoid-terpenoids found in plants like soy and marigolds, it gives you some idea of the kind of data we need for cannabis, then we can provide the precise spectra cannabis requires for peak terpenoid production.
I hope that makes things a little clearer on the UV-A/violet to increase taste and smell theory that I intend to explore. I am going to flower a set of clones without any added UV/violet/blue light then flower another set of identical clones with added UV/violet/blue light and see if there is any change in the taste and smell, it is also possible that the nature of the psychoactive effects could be altered as terpenoids also affect the nature of the effects of cannabis.
I love trippy, psychedelic effects, and it is maybe the case that there are certain terpenoids that work in conjunction with THC and other substances to create these trippy effects, if this 'trippy terpenoid' can be identified and the peak wavelength determined, then I could use LEDs to provide lots of light at this particular wavelength and increase the trippy nature of the effects. There is a lack of readily available information on this subject, given the illegal nature of cannabis across most of the globe, there is very little scientific study being done on this subject.
lilo said:
Don't know how much you can zoom in, but this seedling had trichs.
Sorry, not picking sides, just saying.
dank.Frank
G
Guest
I doubt any seedling has trichomes, I have never seen one although I have seen trichomes on vegging mature plants. dank.frank, do you have a macro capable lens and can take a picture of the 'trichomes' you have seen on that seedling, they may be cystolith hairs or something else, I really doubt they are trichomes. I do not believe that trichomes are produced in response to UV as plants grown without UV are still resinous.
C
Cozy Amnesia
dank.frank said:
Don't know how much you can zoom in, but this seedling had trichs.
Sorry, not picking sides, just saying.
dank.Frank
As in little fuzzy hairs, or actual crystals?
