10.0 UVB help! Proximity to plant? Are 2 bulbs too many?

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Benjammin'29201

Member
I've got a beautiful Black Widow female from Mr. Nice thats just started her 6th week of flower (she'll go minimun 10 wks), and I just hooked up a 10.0 UVB 26w CFL reptile light in the corner of my 400w hps reflector. Its on a seperate timer to be on the middle four hours of my 12 hour light cycle. I was looking to add some uvb the last month of flower to get the extra trichome production that everyone wants.. My questions are exactly how far from the plant is best to have this CFL, and since its only realy hitting one side should I move it around or get another seperate 26w CFL for the other side? Or would that be too much uvb...

Please Help!!
 
Dirt Bikin Buds

Dirt Bikin Buds

Well-Known Member
The UVB CFLs are very concentrated so you do wanna move it every few days or so or get 2 more. It should be 8-12 inches away from the plant.
 
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Benjammin'29201

Member
Wow beautiful! So you guys are firm believers in the uvb leading to bigger trichomes as well.. This is my first grow trying it. I'll grab another 10.0 26w cfl and put it on the other side. People tell me its the difference between great buds and connoisseur buds..
 
tpsmc

tpsmc

Well-Known Member
I just added one to my grow and i have it hanging in the middle of the canopy between the colas. got it on same timer as 1k hps added start of week 4 of flower 8 - 9 week strain.
 
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Benjammin'29201

Member
Thankyou for the pics and explaination brother. its much appreciated. This is the original Widow I'm growing... I'm predicting a monumental amount of juicy trichs with these extra uvb's..
 
Mercer

Mercer

Member
hmm interesting, im going to have to try it, just a regular reptile bulb? and would it help other than just trichome production?
 
kbz

kbz

Active Member
Uvb doesn't harm ur plant unless you over do it. They get uvb all day outside so i don't understand why every indoor grower doesn't use em. Its been proven that the most potent outdoor strains come from part of the earth that have the highest uvb index. I added one to my room after i researched it a little and ever since ive noticed an increase in trichs and the smell of the buds are a lot more complex and strong. I run a desert t5 and on the box it tells you at what distance for what strength. I can't remember the index that afghanistan has but that area gets the highest uvb index. Look up the index for that area and you will know how much to give your plants. I keep mine at 10 inches at an angle that hits the entire canopy. At 10 inches my plants are getting hit with a uv index of around 5. I could put it even closer but i wont get the coverage. I want to say afghanistan has a uvi of 12 most of the year if i remember right. check it out and good look. that b widow is looking potent as ever too good shit.
 
progenitor04

progenitor04

Active Member
kbz said:
Uvb doesn't harm ur plant unless you over do it. They get uvb all day outside so i don't understand why every indoor grower doesn't use em. Its been proven that the most potent outdoor strains come from part of the earth that have the highest uvb index. I added one to my room after i researched it a little and ever since ive noticed an increase in trichs and the smell of the buds are a lot more complex and strong. I run a desert t5 and on the box it tells you at what distance for what strength. I can't remember the index that afghanistan has but that area gets the highest uvb index. Look up the index for that area and you will know how much to give your plants. I keep mine at 10 inches at an angle that hits the entire canopy. At 10 inches my plants are getting hit with a uv index of around 5. I could put it even closer but i wont get the coverage. I want to say afghanistan has a uvi of 12 most of the year if i remember right. check it out and good look. that b widow is looking potent as ever too good shit.
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this is a copy n paste

There is some speculation that exposure to UV may increase potency in mj plants.I believe the theory is that the trichomes shape (round) may cause the UV light to be focused and concentrated in the trich,not unlike a manifying glass,thus causing a photochemical reaction which causes an increase in the THC in the trich.
I have tried several experiments using cut MJ,and placing it under UVB exposure while curing to see if it had any effect on the potency.I did not to seem to have any effect that was noticable.
The reason I didn`t try this on growing plants is the damage it can do to the growing plants.UVB causes everything from DNA damage,to problems with the stomata size.About the only thing it may do is increase the flavinoid compounds in the plant.This may make for better taste,but still damages the plant.There is also a decrease in dried matter,and mass in the plant.In other words,you`ll end up with less of a harvest.
I still believe that the UVB in sunlight has a beneficial effect on the potency of plants,but thats Mother Nature,not harsh exposure to UV lamps.Perhaps if you can simulate the same UVA,UVB AND UVC that the sun produces,you may be able to increase the potency.Another experiment you can try is once the plants are cut,you may try to dry and cure them out in the sun.The proper amount of UV may make a difference,but I`m just speculating.

There are a lot of experiments going on with UV and plant exposure due to the increasing ozone problems and increased uv exposure on plants and animal life.So far there is not much good that is coming out of UV exposure.

Just my personal opinion,but I wouldn`t expose my plants to too much,or unknown amounts of UV light.I believe it will just do harm to your plants,and will damage other materials(plastics fabrics wood etc etc) that are exposed to too much UV light.Not to mention you certainly don`t want to expose your eyes to UV.Couple of articles below that may interest you.

The visible light spectrum, known as photosynthetically active radiation (PAR), is of paramount importance in plant growth in that PAR light is responsible for driving photosynthesis. However, the role of ultraviolet radiation (UV) in promoting plant growth and survival is less well understood.

UV light itself is classified in three spectral regions: the ultraviolet A light (UVA) is of wavelengths of between 320 and 400 nm; ultraviolet B light (UVB) is of wavelengths between 280 and 320 nm; and ultraviolet C light (UVC) is of wavelengths between 180 and 280 nm. The ea is bathed in both UVA and UVB light. However, UVC light is almost entirely filtered out by the earth's atmosphere.

Ultraviolet light in the UVB range is higher energy than UVA and responsible for damage to cells and tissues particularly with exposure to low wavelength UVB light. UVB radiation effects on plants that are attributed to susceptibility to pests, for example, include DNA damage (Britt, A. B., Trends Plant Sci, 1999; 4:20-25), modification in gene expression (Savenstrand, H. et al., Plant Cell Physiol, 2002; 43:402-10; Brosche M. and Strid A., Physiol Plant, 2003; 117:1-10), changes in secondary metabolism (Feucht W. et al., Vitis, 1996; 35:113-18; Picman A., et al., Verticillium albo-atrum Biochem Syst Ecol, 1995; 23:683-93; Glassgen W. et al., Planta, 1998; 204:490-98; Norton, R., J Agr Food Chem, 1999; 47:1230-35; Wicklow D., et al., Mycoscience, 1998; 39:167-72), and changes in leaf anatomy, i.e. leaf thickness and cuticle thickness (Garcia S., et al., Phyotochemistry, 1997; 44:415-18; Liakoura, V,, et al., Tree Physiol, 1999; 19:905-08; Raviv, M., and Antignus, Y., Photochem Photobiol, 2004; 79:219-26). Additionally, UVB light causes plants to produce UVB absorbing compounds, such as flavonoids and other phenolics, phenolpropenoids, alkaloids, and terpenoids. These secondary responses are generally independent of photosynthesis and produce photomorphogenic responses in UVB recipient plants.

Early experiments analyzing solar UVB effects demonstrated substantially reduced photosynthesis, plant growth, and crop yield. However, these early experiments were performed under unrealistic spectral balances in that high levels of UV were used. In experiments employing balanced levels of UV radiation, UV-induced partitioning of carbon to production of secondary plant metabolites occurs. Enhanced UVB radiation stimulates production of phenolics and flavonoids that serve a protective role by accumulating in leaf epidermal cells and attenuating UV radiation before encounters of sensitive processes in mesophilic cells. Synthesis of bulk methanol soluble UV absorbing compounds increases by 10% following enhanced UVB radiation.

Glasshouse manufacturers continue to claim that blocking UV radiation shows beneficial effects on reducing plant pathogens and insect pests. However, the presence of UV radiation, including high--energy UVB radiation, is actually beneficial to plant physiology and development. Indeed, when plants are subjected to UV light in addition to PAR many benefits are observed including insect and pathogen resistance and elevated levels of DNA repair capability. The reduced crop yields long thought to be the hallmark of increased ultraviolet light exposure, have recently been demonstrated to be inaccurate. The positive effects of UV radiation are not observed unless full spectrum light is present, including UVA, UVB, and photosynthetically active radiation. However, in radiation controlled studies in which UV and PAR are used simultaneously, high doses of UVB radiation relative to UVA causes some leaf damage in plants suggesting that the more unnatural the spectrum, the greater the damage caused by ultraviolet radiation. (Krizek, 1993; Caldwell, 1994.)

Gene expression is positively regulated by exposure to natural levels of ultraviolet radiation. As many as 70 UVB responsive plant genes have been identified that control mechanisms such as photosynthesis, pathogenesis, and the generation of antioxidants, Several processes regulated by UVB radiation are related to increased or enhanced plant color or fragrance. This modified genetic expression, translation, or modification pattern in the presence of UVB radiation partially explains why clones from the same plant grown in artificial lighting and sunlight look, taste and smell different than their genetic identicals grown in natural sunlight.

A majority of plants show significant benefit from ultraviolet light. Many of these are economically important plants such as herbs, drug producing plants, ornamental flowers, and food crops, Benefits of UV light include increased immune responses, enhanced pigmentation and aroma, and altered plant architecture such as shape, flower number and volume, and thricome density. A **** analysis of numerous plant species suggests that insect damage actually decreases with increasing doses of UVB light. (Bothwel, 1994; Mazza, 1999.) This response has been demonstrated in agricultural as well as in native plants. (Id.; Rousseaux, 1998.) For example, Isaguire, 2003 showed that expression of 20% of insect fighting genes of tobacco are increased after exposure to UVB radiation. These include proteinase inhibitors that inactivate insect digestive tract (Ryan, 1990) and furanocoumarin that results in slower development of insect larvae (McCloud, 1994). Production of insect repelling phenols is also observed following increased solar UVB radiation. (Fuglevand et al., 1996.) Defense to insects includes the formation of flavonoids or pigments that absorb UV in the 220 to 380 nanometer range. (Ormrod, 1995.) It is hypothesized that flavonoids and other chemicals produced in response to UV shield the plant by absorbing light in the UV range, inhibiting insect attachment and further scavenging free radicals.

Supplemental ultraviolet light on tomato plants produces a thickening of the skin that also increases resistance to insects such as boring insects. Other beneficial characteristics are simultaneously present such as the flavor of the pulp is considerably more complex and desirable. Fruit skin toughening is also found in naturally increased UV exposure. In analyses of plants in Tierra del Fuego on the southernmost tip of South America, which is regularly affected by severe ozone depletion increasing the levels of ultraviolet radiation exposure from the sun, insects prefer plant tissue before it is exposed to UVB light
 
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growman27

Member
Amen to the afghan.... at one point i was a soldier and deployed to afghanistan. I have seen huge fields of the stuff and it is amazing.
 
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WickedSmoke

Member
Not sure of this was stated in that giant copy and past. But from what I researched the thought about out door mj plants being more potent, or producing more resin is due to the fact that our plants build up resin like sun lotion, to protect its self from UVA and UVB radiation. So why not use this in the grow room?
 
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Bonzo Mendoza

New Member
kbz said:
I want to say afghanistan has a uvi of 12 most of the year if i remember right.
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No, that's not correct. At any latitude higher that 15-20 degrees, uvb falls off to almsot nothing in the winter b/c of low sun angle.

Sun angle is hugely important for uvb illuminance - uvb is highest in northern latitudes around the Summer solstice.

For pot growers, in my experience, blasting the shit out of one's indoor with uvb is not necessary and (probably) counterproductive - it does not take very much uvb to cause a strong reaction in the plant. A little is enuf.

Also, thc absorbs uvb - this is important!!! As I understand the uvb/MJ articles I have read, absorption of uvb is probably an adaptation of the MJ to protect the plant from uvb damage. Thc resin is MJ sunscreen. It is likely that uvb demolishes thc molecules. Pay attention here: do you really want to take the risk of destroying a phat cola glistening with resin by blasting it with uvb in the last two weeks of flowering???? In my experience, the uvb lights can be turned off for at least a week before the plant figures it out.

Lastly, I am deeply suspicious of the claims made by uvb cfl manufacturers - a cfl is inherently flawed (too many twists and turns in the bulb) for generating uvb. I can locate no zoo that uses uvb cfls - they all use straight tubes.
 
DO3SHA

DO3SHA

Well-Known Member
Bonzo Mendoza said:
No, that's not correct. At any latitude higher that 15-20 degrees, uvb falls off to almsot nothing in the winter b/c of low sun angle.

Sun angle is hugely important for uvb illuminance - uvb is highest in northern latitudes around the Summer solstice.

For pot growers, in my experience, blasting the shit out of one's indoor with uvb is not necessary and (probably) counterproductive - it does not take very much uvb to cause a strong reaction in the plant. A little is enuf.

Also, thc absorbs uvb - this is important!!! As I understand the uvb/MJ articles I have read, absorption of uvb is probably an adaptation of the MJ to protect the plant from uvb damage. Thc resin is MJ sunscreen. It is likely that uvb demolishes thc molecules. Pay attention here: do you really want to take the risk of destroying a phat cola glistening with resin by blasting it with uvb in the last two weeks of flowering???? In my experience, the uvb lights can be turned off for at least a week before the plant figures it out.

Lastly, I am deeply suspicious of the claims made by uvb cfl manufacturers - a cfl is inherently flawed (too many twists and turns in the bulb) for generating uvb. I can locate no zoo that uses uvb cfls - they all use straight tubes.
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This has been a big debate for along time now UVB is used by a lot of growers with better quality buds at the end, They say if you use UVB you will get better quality buds but a lower yield, others say it won't even effect yield and still give you better quality buds

Obviously UVB can be used and is used in most legitimate led panels now days. Most of theses panels use UVB and IR so UVB can't be that bad for plants if they are putting it in the panels
 
polyarcturus

polyarcturus

Well-Known Member
uvb is good.

10.0 around 18" for the first week or so (read the guide there is a burn in period) then after that about 12" is perfect its better to have the UVB at the sides of the plant if you can. i use a 160w MVB and my results where great UV has never affected my yield in a negative manner but then again im not hitting the level tha are what the sun produces... but then again outdoor plants yeild more, anyways you do the math. IMO UVB and plenty of it is good.
 
L

lansingautorepair

New Member
I just completed 2 full years of testing on over 10 different strains and have reached the conclusion that the uvb uva light spectrum will add 3-5% THC and .0-.5% bcd over all strains tested.



I published my research on Academia.org Here is a link to my notes as well as research I found in my search to learn as much as I could about the UVA/UVB subject.

http://medicalmarijuanagrowing.blogspot.com/2013/02/uvb-uva-lighting-study-results.html

I use 6 double rowed 4ft shop style lights. With 2 10.0 bulbs in each light assembly! No issues whatsoever!
I run them on the outside walls of my room and hang 2 over head between my bloom lights.

Veg is a waste of time really just run them right away in the bloom cycle so they will adjust. Leaf curl is normal the new growth will adjust and won't curl.

My HGK is consistently testing at 28% with the UVB lights and 24% without. My chem dog is 27%. Everyone who has tried each batch always asks what I did different because the high is so much higher with the lights. I also use the dual arch super blues with Canna/Rock nutrients so resin production is incredible.

It is great to see others finally trying this out and seeing the results. Most growers think we are full of it.
 
X

xertion123

Active Member
lansingautorepair said:
I just completed 2 full years of testing on over 10 different strains and have reached the conclusion that the uvb uva light spectrum will add 3-5% THC and .0-.5% bcd over all strains tested.



I published my research on Academia.org Here is a link to my notes as well as research I found in my search to learn as much as I could about the UVA/UVB subject.

http://medicalmarijuanagrowing.blogspot.com/2013/02/uvb-uva-lighting-study-results.html

I use 6 double rowed 4ft shop style lights. With 2 10.0 bulbs in each light assembly! No issues whatsoever!
I run them on the outside walls of my room and hang 2 over head between my bloom lights.

Veg is a waste of time really just run them right away in the bloom cycle so they will adjust. Leaf curl is normal the new growth will adjust and won't curl.

My HGK is consistently testing at 28% with the UVB lights and 24% without. My chem dog is 27%. Everyone who has tried each batch always asks what I did different because the high is so much higher with the lights. I also use the dual arch super blues with Canna/Rock nutrients so resin production is incredible.

It is great to see others finally trying this out and seeing the results. Most growers think we are full of it.
Click to expand...
So you use UVB and UVA? Do you have to use both? If I'm running a 400w HPS during flower how much UVB should I add?
 
ganjaguru_420

ganjaguru_420

Active Member
I know this thread is a little old but I added a 10.0 reptile bulb and I checked my plant in 2 hours and the leaves were drooping and had brown spots on em. I had the light about 4 inces away from the tallest point and leaves on the bott were the same way. I tried it on a green crack on its 3rd or 4th week of flower. So be careful and if you try it check it often. It's been a day since and the leaves are back to normal except the brown spots
 
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