Uvb And Thc Production

[Stoke]

In Ed Rosenthal's book he mentions giving your plants UVB in the last 2 weeks of flowering to increase THC production. My grow room is 5 x 5 x 8, and I'm using 1 1000w HPS bulb with a Lumatek digital ballast, and the bulb/reflector is closed loop air cooled.

So according to Rosenthal, my problem is that HPS bulbs don't provide UVB. I could switch to a 1000w MH bulb to get some UVB, but he also mentions using tanning lamps, or those CFL's used in lizard cages. The great thing about the MH bulb is I can use them with no problems with my ballast.

In addition, the biggest issue is the glass on the bottom of the reflector. That glass blocks UVB (and diminishes other light in the spectrum). However, according to him, removing the glass on the reflector shouldn't make cooling the light any less effective; my air cooled system should still work effectively.

So what is everyone's thoughts? Would replacing my HPS bulb with an MH bulb in the final weeks of flowering be sufficient enough? Or do I need additional sources of UVB? Do you agree that I should take off the glass on the bottom of my reflector? Anyone with a difference of opinion?

Thanks for any feedback! Feel free to recommend an MH bulb for me to use with my ballast, or any other recommendations you feel would work best for my setup.

 

[johnnyrotten]

If you aren't using glass on your reflector isn't it going to suck smelly air through the exhaust?

You could use an MH bulb but it will put out less light than the HPS...I see plenty of frosty, dense nuts being grown with HPS bulbs on the forum...I personally would run the HPS all the way through...it's proven to work...

 

[Seamaiden]

HPS provide no UV wavelengths at all. You can add simple fluoros to get some UV radiation into the mix, easily. I would not play around lightly with certain UV wavelengths, which is why I generally don't discuss it in open fora.

Yes, you can also use the daylight bulbs sold for lizards & reptiles that require light for synthesizing Vit. D, but they're more expensive. What I would do, if you're interested in getting some UV in there (UVA & UVB) is I'd get a shop light, 4' if it'll fit, double-tube fixture, and pop some cool white or daylight bulbs in it. Or a couple of fixtures, they're cheap enough. You can lean them against the wall if you want, just be careful moving around them, etc. I think it's easier to add them to the sides with chains and hooks.

 

[Natural]

I was chasing this rabbit for a good long while. I came to the conclusion that I do not need UVB. Honestly, if my buds were any stronger I would hear complaints. I use HPS in glass hoods, there is no difference in yield or quality compared to open hoods. Just pulled 62 ounces of Stardawg from 10 plants using 2k hps in glass hoods and fresh air exchange (no CO2). IMVHO..if you want more crystal laden and stronger potency buds, I recommend concentrating on genetics, environment, and nutrition.
If you are just experimenting..I would try the MH for the last 2 weeks. Folks tend to have success with doing that. I never hear anybody professing and jumping up and down that reptile lights or shop lights are game-changing in any way.
my 2% of a dollar

 

[Stoke]

I was chasing this rabbit for a good long while. I came to the conclusion that I do not need UVB. Honestly, if my buds were any stronger I would hear complaints. I use HPS in glass hoods, there is no difference in yield or quality compared to open hoods. Just pulled 62 ounces of Stardawg from 10 plants using 2k hps in glass hoods and fresh air exchange (no CO2). IMVHO..if you want more crystal laden and stronger potency buds, I recommend concentrating on genetics, environment, and nutrition.
If you are just experimenting..I would try the MH for the last 2 weeks. Folks tend to have success with doing that. I never hear anybody professing and jumping up and down that reptile lights or shop lights are game-changing in any way.
my 2% of a dollar

If I was going to experiment with finishing off using an MH lamp, should I go 6k or 10k? I'm looking into these:



Solis-tek recommends 10k, but what about you guys?Will Solis-tek lamps work well with a Lumatek digital ballast? I've heard Hortilux's are kind of sketchy.

 

[Natural]

If I was going to experiment with finishing off using an MH lamp, should I go 6k or 10k? I'm looking into these:



Solis-tek recommends 10k, but what about you guys?Will Solis-tek lamps work well with a Lumatek digital ballast? I've heard Hortilux's are kind of sketchy.

You actually called them and they recommend the 10k for more UVB? ..and what's up with "higher yield"??...shit man everybody knows MH will give you more potency and less yield...hence the reason peeps only use it at the end of flower and not the whole way through.
Personally, I would use the 5000k because it would be more of a "full spectrum" type lighting that is closest to natural daylight..but that's not necessarily going to give you more UVB. Kelvin has more to do with an arbitrary system of visible light and it's color and has little to do with how much artificial ultraviolet radiation a bulb emits. They're being slick by posting the wavelength charts and then posting the kelvin rating without any correlation. Then all they mention is that their bulbs are made with low-iron to alow UV radiation to pass through less filtered. An educated guess is the MH's would be comparable to each other in UVB output without the kelvin rating. Ceramic metal halide is most likely going to put out the most UVB of all the halides imho. Just be sure to lessen your exposure and wear eye protection.

 

[Stoke]

You actually called them and they recommend the 10k for more UVB? ..and what's up with "higher yield"??...shit man everybody knows MH will give you more potency and less yield...hence the reason peeps only use it at the end of flower and not the whole way through.
Personally, I would use the 5000k because it would be more of a "full spectrum" type lighting that is closest to natural daylight..but that's not necessarily going to give you more UVB. Kelvin has more to do with an arbitrary system of visible light and it's color and has little to do with how much artificial ultraviolet radiation a bulb emits. They're being slick by posting the wavelength charts and then posting the kelvin rating without any correlation. Then all they mention is that their bulbs are made with low-iron to alow UV radiation to pass through less filtered. An educated guess is the MH's would be comparable to each other in UVB output without the kelvin rating. Ceramic metal halide is most likely going to put out the most UVB of all the halides imho. Just be sure to lessen your exposure and wear eye protection.

Thanks for the info. I didn't call them, it's listed on the product page for the 10K to use that one during the last weeks of flowering.

I'm not buying into any of their marketing. They also mention the whole, "UV" thing with their HPS lamps, but everyone knows HPS lamps don't emit UVB. I've just done a little research into their lamps, and a lot of people recommend them.

Do you know of a company that offers a good ceramic MH lamp that would work with digital ballasts?

 

[Natural]

I think Sunpulse has something that works with digi's..I would look up the 1-800 Ushio number and pick their brains as well. Phillips and GE are in on the game too. I find it somewhat amusing to call the reps of these companies..9 x's out of 10 it ends up being a fun conversation. Tell em what you want without telling them what you do...sounds easier than it is..lol. I want UVB radiation damnit..lol...some of these bulbs are protected so they don't harm anything. You really got to watch your eyes and skin working under these..they don't come in sizes over 400w. I would think it would be a good supplement light on a bigger grow..right there after the mid-day mark for the recommended 4 hr run. But some are running them full time on smaller grows. I would think too close would give them sunburn like it does to us if they get too close..but I'm no CMH expert by any terms.

 

[Stoke]

Funny you mention Sunpulse. Once I made that post I went off to do research, and they were one of the companies I found. They seem very intriguing. They make 1000w bulbs in 3-10k that do work with digi's. I looked at Philips and Ushio too, but so far I'm liking Sunpulse the most. Still more research to do, and I found a topic on this site discussing them. Haven't been able to read through it yet but here it is if anyone is interested:
https://www.thcfarmer.com/community/threads/sunpulse-lamps-4k-6-5k-3k-and10k.12759/

Reading up on Sunpulse's is even making me think about ditching HPS altogether, but I don't think I'm there yet. The main thing about them (besides the added benefit of UVB) is the light they produce supposedly is more closer to the sun compared to HPS.

 

[Stoke]

Hm yeah, scratch that last part. It seems like most people who got great results doing a full grow with just the Sunpulse's were using a multi-light setup. I've got just the 1 hood for mine. However, I'm reading about great results from people using the 10k one in the final weeks of flowering. Sunpulse has a new model out (or coming out soon) and they are offering the older model 1000w 10k's for $35 so I'd say that's worth an experiment.

 

[Seamaiden]

I find it fascinating that a bulb with a Kelvin rating that's typically used in reef aquaria is what they'd recommend for a higher UV of any band output. Have you ever seen the light from a 10,000K bulb? Almost no red.

 

[2hotmomma88]

I used the lizard light on my plants. Very frosty. Used last 3 weeks of budding. 70 bucks for one bulb. I had a small grow so I would switch them up under the light. 50 bucks on amazon.

 

[Natural]

Hm yeah, scratch that last part. It seems like most people who got great results doing a full grow with just the Sunpulse's were using a multi-light setup. I've got just the 1 hood for mine. However, I'm reading about great results from people using the 10k one in the final weeks of flowering. Sunpulse has a new model out (or coming out soon) and they are offering the older model 1000w 10k's for $35 so I'd say that's worth an experiment.

New bulbs huh?..interesting. I saw you posted up in the Best Bulb for Flowering thread. I take TK's word as gospel..on the simple fact that he has the most experience in production speaking on the matter. Hope you get a chance to re-read post #34 & #36. Pretty much sums it up for me when it comes to the Sunpulse experience. I only run 4 lights..but I keep coming back to these new philips bulbs and the epaps..exciting stuff goin on.

 

[Stoke]

New bulbs huh?..interesting. I saw you posted up in the Best Bulb for Flowering thread. I take TK's word as gospel..on the simple fact that he has the most experience in production speaking on the matter. Hope you get a chance to re-read post #34 & #36. Pretty much sums it up for me when it comes to the Sunpulse experience. I only run 4 lights..but I keep coming back to these new philips bulbs and the epaps..exciting stuff goin on.

Yeah, I found that thread before making this topic, but it kind of went off topic in the end so I thought I'd make a new one here. I've re-read it a bunch of times, and TK's post were encouraging about finishing off using a 10k bulb.

I've heard great things about Philips' CMH bulbs. I read about someone's experience with them on another forum and saw some pics of bud grown under them, and they sounded/looked awesome. It's too bad they don't work with digi's, and I don't think they have anything above 600w yet (the thread was a few years old so maybe things have changed?).

 

[Natural]

@Capulator uses the single ended Phillips' bulbs on the epap ballasts (I'm pretty sure it's not gavitas) and they have the select-a-watts. He says they are running somewhere around 660 watts and they are keeping up with the 1k's. He's running the single ended Phillips' bare bulb I do believe. Not exactly sure about these Phillips' or the double ended and their spectrums..I'm thinking they are full and giving off UVB..but I'm still in research mode on these.

 

[Capulator]

@Capulator uses the single ended Phillips' bulbs on the epap ballasts (I'm pretty sure it's not gavitas) and they have the select-a-watts. He says they are running somewhere around 660 watts and they are keeping up with the 1k's. He's running the single ended Phillips' bare bulb I do believe. Not exactly sure about these Phillips' or the double ended and their spectrums..I'm thinking they are full and giving off UVB..but I'm still in research mode on these.

It's a gavita 1000w remote ballast with a Philips 600w 400v greenpower bulb, ballast cranked to 660w.

The CMH bulb is a 315w but will perform like a 8 lamp 500w t-5 fixture with a better spread. Philips makes one called a d-pap. cycloptics reflectors also has one that is really nice, but expensive.

Philips makes the bulb for all gavita fixtures.

 

[Capulator]

Oh and if you do use UVB lights you only use them for 30 minutes or so a day, and you will get more frost because the Trichomes are acting a s a "sunscreen". Probably not worth the set up costs for most and most good strains these days are already covered in frost under regular HID lights.

 

[2hotmomma88]

Oh and if you do use UVB lights you only use them for 30 minutes or so a day, and you will get more frost because the Trichomes are acting a s a "sunscreen". Probably not worth the set up costs for most and most good strains these days are already covered in frost under regular HID lights.

This was my first grow I figured I needed all the help I could get lol.

 

[BrotherGreen]

I have also read that UV can turn CBDs back into THC and with that rescue moldy buds.
I have done some experimentation using an old hand held UV light (so potent you could smell the ozone it was generating). It did make the moldy dirt-weed more potent but did not do much to rescue the taste.
I was never able to see any difference in amber or milky trichomes after treatment. If there was a difference it was so minute that I was unable to detect it and found it a waste of time.
Ed's hypothesis comes from the high THC content found on weed grown in higher elevations. After months of research (the old college try) I found the benefits did not out weigh the detriments. I did find that any treatment made the plants weaker in some aspect and therefore more vulnerable to attack (mold, mites).

 

[Jalisco Kid]

T100 100w uvb bulbs are a nice bulb for the amount of funtickets they want for them. JK

Here is a little info on a few of their bulbs