Do you add UVB light to your grows?

I've been reading a little about adding ultra violet light (UVB) to pump up the THC levels. There are different cfl bulbs that are rated like 5.0, 10.0, etc and this is confusing. I don't know what that means or which I should use during flowering, or how far from the plant tops should it be and should it run 12/12 as well?

I just added one in yesterday to my small incubator. 13 watter from walmart and next day I noticed a big diff in trych prod. But I'm also new at this and I don't really know either how long to run it....I just put it at a 45 deg angle at the left hand corner pointing towards the canopy... I got two ufos in there..... 4 LGM5's and two 24 watt Cfl tubes on the sides... I'm just gonna run it 12/12 with the rest and see what happens... But deff noticed a big diff just in one day no BS! Marijuana man makes alot of sence....

Great! - You would run it on 12/12 in sync with your flowering lights. Please keep me posted, I want to know if it makes any real difference in trichome production at the end of the grow. I here lots of folks say it does, but how much I dont know. This is new to me and I'm always on the lookout for new ways to improve. I was hoping this would get more action....Help!!!

I read a lot about this and sum up what I found most people say:

• Some strains respond to it, others not so much
• Be VERY careful with UV-B lights - skin cancer and blindness are no fun
• Most run UV-B 4-6 hours in the middle of the light-cycle
• Zoo Med ReptiSun 10.0 Desert bulbs are recommended

dontcopnone said:

I read a lot about this and sum up what I found most people say:

• Some strains respond to it, others not so much
• Be VERY careful with UV-B lights - skin cancer and blindness are no fun
• Most run UV-B 4-6 hours in the middle of the light-cycle
• Zoo Med ReptiSun 10.0 Desert bulbs are recommended

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That's what I was looking for. Any idea WHICH strains benefit most from UVB light?

I think they would all benefit from it.. Especially the strains that are native to the equator witch recievee much more UVB and are far more resinous. So far they are responding well to the light and I run it 12/12 with rest cause it's only a 13 watter... I'll keep u posted. But its suposed to stress the bitch in a way that it's natural defense is to produce more resin. More resin= more cannabanoids and more THC.

HomeGrownHairy: No. The best you can do is test it yourself on whatever you're growing. Just remember to be VERY VERY careful with it. I'd recommend having a way to shut them off from outside of your grow before you enter to limit exposure.

Also, the reason most people give for using that light-cycle is to mimic that of nature. UV emission peaks during the middle hours of the day when the sun is highest in the sky.

Mr.Niceguy03: People report otherwise. Also the theory goes far beyond "stress" - there's information on the web that suggests trichomes act as a lens to focus light. UVB is said to be integral to the production of THC inside the trichome. The reason that people run the UVB bulbs shorter than 12/12 is that it can easily burn plants. Look what it does to humans - goes right through our skin, rips apart DNA, causes cancer. If you're lucky it just causes a sunburn.

if this is what i think your talkin about i read in high times that you could drop your darkness time during flowering by n hour n half or 2 by taking a uv bulb in covering it in some kind of tint and basically for lack of sayin it better "spraying your plants with uv light right as the 12 hour light cycle ends and this will speed your plant up to setting into its flowering stage or somthing. i dont remember the article exactly ill have to find it. but doin this you can actually have like a 13 11 light cycle n still flower. but like i said i dont remember the article exaclty so this could be wrong.

I've never used UVB lights but I know they are useful in flowering but are they any use in veg?

Not really. People use them to increase trichome production.

dontcopnone said:

Not really. People use them to increase trichome production.

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oh ok , I thought UVB would do some thing for the plants in veg

Nope. It's not a growth stimulator in the classical sense.

dontcopnone: ur absolutely right about the tryc head acting as a lens to absorb light and start process of cannabinoids...but I was just so impressed by the way it raised tryc production and it's low wattage I thought I would run it 12/12 with the rest.. So far they look fine but if I start to see it start to affect my girls in a bad way then I'll consider getting a seperate timerxand just run it a few hours in the middle of 12/12. Thanks for ur input I'll make sure I shut that bitch off before opening it to limit exposure.. I always put my raybans on when working on them with the lights on anyways... Damn LEDs have me seeing green for 10 min after of I don't wear shades....LOL

yup, I saw it increases the quantity of fulliy developed THC by 23% over only hps, that is to say 23% of what it would be.

if a person is using CFLs for flowering could they use 2 UVB lights insted of just 1?

If you want better coverage, I guess you could use 2. The type of main bulb you are using does not matter. My personal research shows that it is often MUCH cheaper to buy them online. My local pet store had Reptisun 10.0 26w CFL's marked up $20 higher than I found them online.

If you can position the light to cover your entire area, one is probably going to be sufficient. These bulbs can throw out a LOT more UVB than natural sunlight, especially if they're too close. Unlike our normal CFL's you probably don't want these suckers to be 2" off your plants.

dontcopnone said:

If you want better coverage, I guess you could use 2. The type of main bulb you are using does not matter. My personal research shows that it is often MUCH cheaper to buy them online. My local pet store had Reptisun 10.0 26w CFL's marked up $20 higher than I found them online.

If you can position the light to cover your entire area, one is probably going to be sufficient. These bulbs can throw out a LOT more UVB than natural sunlight, especially if they're too close. Unlike our normal CFL's you probably don't want these suckers to be 2" off your plants.

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I'm thinking about using 2 45w 2,7ooK CFLs in a flowering space but I might go with 15w CFLs and a UVB. I'm gonna be buying 96% reflective mylar to though

UVB should be seen as a suppliment to the normal bulbs, not a replacement. Besides, UVB is the least of your concerns. Two 45w CFL's is not going to be enough light for even 1 square foot. From what I've seen online a 45w should put out about 2900 lumens, two would total 5800 lumens. Aim for at least 7000 lumens per square foot. If you only have 3 sockets, find the biggest 2700k CFLs you can and forget UVB.

Stop dreaming about the monster buds you're going to grow and actually read some CFL grow reports. Most have 200w or more total light, even in small spaces. You can't give a plant the bare minimum and expect results.

I read somewhere that Metal Halide lights produce UVB... anyone heard of this?

...What would the benefit of running a MH light in flowering?

say a 1000W hps and a 400W MH

Edit:6500K spectrum on the 400MH (daylight)

Ask Ed.

Short answer: MH produce too little UVB to make a difference. The outer glass is designed specifically to block UV light. As far as whether MH or HPS is better for flowering, who knows. Some say MH flowering will give you super compact, but less potent buds and HPS gives slightly looser buds but increased potency. Some state differences in yeild. One grow report I vaguely remember had a 400w HPS running beside a 400w MH (in hoods, no light mover) and the grower reported results were best in the middle where both lights mixed. I've even had a wonderful conversation with one of the guys at my local hydro store who reported many local "vegetable" growers were getting stellar results from running dual arc bulbs (SolarMax One - 1000w bulb with 600w HPS element and 400w MH).

Want to know for sure? Buy a switchable ballast or conversion bulbs and test for yourself.