Ive been doing a lot of research on how uv-c kills pm. I know if you do it for small amounts each day for about a week it should take care of it. But i just dont know how many watts the uv-c lamp wold need to be to work. If anyone has any input that has exeriance with this subject it would help a lot. I have a 4x8 grow tent.
 
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163
I read that uv-c is hella deadly and will turn your skin black and give you cancer. No exaggeration. Not even kidding. Jalisco Kid on this site doesn't even recommend any exposure to the (supposed to be much safer) uv-b.

Just get a small metal halide to shine in your tent, maybe a 75 or 100 watt hung vert above or something. You will get uv from that. Turn it off when you access your tent.
It will have a germicidal/fungicidal effect. But I do not know how much.

And read about uvc dangers. It will scare you away like it scared me away. For good reason. It can literally give you cancer and kill you.
Stay safe homey.
 
wavelengths between 200-280 are UVC and they are extremely toxic to plants. To give you an example UVC sterilizers are used to make grey water suitable for drinking.
 

theherbalizor

Premium Member
Supporter
1,414
48
Uvc is a light spectrum... Not a toxin. It is not toxic to plants.

However, it destroys and mutates DNA on long term exposures.

Germicidal uvc bulbs for horticulture are nothing new, infact cleanlight.nl make a hobby uvc light for use on fungus etc on house plants, weed.

This is not a gimmick, it works. Has been used in the commercial industry for years.

Floweryfields of Austria use uvc in their daily plant maintanace.

But do not ever get your skin exposed to uvc or your retinas / eyes. Small exposure will cause serious sun burn type effects and long term exposures will almost certainly be a trigger for certain cancers.

IMO, some of the anti thrip/ mite stuff that we spray or smoke unknowingly is much more dangerous to us than if we use uvc correctly. And the cleanlight comes complete with uvc filter goggles and gloves.

UVB has no effect on pathogens. You will not get uvc from a mhal bulb of any kind.

Powdery mildew requires around 1800 u watts of uvc to kill the spore. On an 11 watt uvc bulb that means a quick once over with the lamp will kill all spores the light falls on.

Good daily short term use not only kills spores but actually helps the plant to develop thicker leaves which again helps to combat pathogens.

Uvc really is the way forward for desease control.

Here is a copy and paste from another site...

.........


Ultraviolt light (UV) occurs from the sun. The wavelength of UV is outside of our visible range. The lowest wavelength colour we can see is violet, hence the name for light with a wavelength lower than this is ultraviolet.

UV ranges from 100 nanometres to 400nm. UV is further divided into UV-A, UV-B and UV-C.
UV-C: ranges from 100nm – 280nm (germicidal)
UV-B: ranges from 280nm- 315nm (sunburn)
UV-A: ranges from 315nm – 400nm (blacklight)

We here are interested in the UV-C rays, also known as „short wave ultraviolet radiation“. UV-C`s germicidal properties have been known since the 1930s. They are used in labratories in order to destroy bacteria, mould and viruses. UV-C rays are able to penetrate the outer membrane of microbes and stop them from reproducing. The specific wavelength of 253,7 nm is known to break the DNA of pathogens.

In May 2007, two Dutch inventors, Arne Aiking and Frank Verheijen were granted an International Patent on a method of treating live plants and mushrooms against pathogens with UV-C light. In the past UV-C had only been used to sterilise things like air and water. The difference with proposing to use UV-C to fight pathogens on living plants is that you shouldn`t use any more than is necessary, otherwise there is a risk to health of the plant.

Mr. Aiking and Verheijens invention is a mobile UV-C lamp that travels up and down in commercial greenhouses. The light intensity of a UV-C germicidal light bulb is usually expressed in a term called „microwatts per square centimetre“. Mr. Aiking and Verheijen suggest a range between 2,500 and 150,000 mircrowatts of UV-C energy over a given 24 hour period.

E.g. A 100 Watt UV-C lamp will output approximately 14,000 microwatts of energy over a square centimetre, in one second, from a distance of two centimetres away. If we leave it there for one minute we have to multiply that figure by 60. (840,000 microwatts). Look at the following chart:
1cm 21,000 µW/cm2 UV output
2cm 14,000 µW/cm²
3cm 10,000 µW/cm²
4cm 8,000 µW/cm²
5cm 6,700 µW/cm²

100cm 360 µW/cm²

This shows that a second`s exposure at 1cm distance is roughly equivalent to a full minute`s exposure 1 meter away (360 x 60 = 21. 600µW/cm²).

We use the UV-C light to fight against powdery mildew in our plantation. Tests have shown that powdery mildew is killed when given a dose of 1720 µW of UV-C per square cm. For exemple if I took a 100 Watt UV-C lamp and positioned it two centimetres away from the mildew, I would need to switch on the UV-C lamp for just 1/10 of a second to kill it.

Spider mites could possibly also be effectively treated with UV-C but with amounts that are hundreds of times more compared to something like powdery mildew. We therefore use it only against powdery mildew.

The safest way to use UV-C on plants appears to be regular, smaller doses rather than a single, lager hit. We therefore use the UV-C light every day for a short time. The pathogen must be hit directly with the UV-C rays in order to be affected. If it is protected by a leaf, the UV-C will not be effective, because UV-C will not penetrate through leaves.

WARNINGS:
UV-C light has an intense burning effect on human skin and can quickly damage your eyes.
Protect your eyes with special eyeglasses
Don`t expose your skin to UV-C rays
The wrong amount of UV-C will damage your plant
This topic is part of one of our next episodes on FlowerfieldTV. We have just started the treatment of our plants with UV-C rays. At the moment we also use sulphur, because we don`t run the risk of getting powdery mildew. After that stage will treat our plants exclusively with UV-C ray. We will regularly report our experiences and tell you our improvements in This thread.

Finally I want to say thank you to Everest Fernandez, who provided a lot of information for this thread.
 
Uvc is a light spectrum... Not a toxin. It is not toxic to plants.

However, it destroys and mutates DNA on long term exposures.

Germicidal uvc bulbs for horticulture are nothing new, infact cleanlight.nl make a hobby uvc light for use on fungus etc on house plants, weed.

This is not a gimmick, it works. Has been used in the commercial industry for years.

Floweryfields of Austria use uvc in their daily plant maintanace.

But do not ever get your skin exposed to uvc or your retinas / eyes. Small exposure will cause serious sun burn type effects and long term exposures will almost certainly be a trigger for certain cancers.

IMO, some of the anti thrip/ mite stuff that we spray or smoke unknowingly is much more dangerous to us than if we use uvc correctly. And the cleanlight comes complete with uvc filter goggles and gloves.

UVB has no effect on pathogens. You will not get uvc from a mhal bulb of any kind.

Powdery mildew requires around 1800 u watts of uvc to kill the spore. On an 11 watt uvc bulb that means a quick once over with the lamp will kill all spores the light falls on.

Good daily short term use not only kills spores but actually helps the plant to develop thicker leaves which again helps to combat pathogens.

Uvc really is the way forward for desease control.

Here is a copy and paste from another site...
...

Ultraviolt light (UV) occurs from the sun. The wavelength of UV is outside of our visible range. The lowest wavelength colour we can see is violet, hence the name for light with a wavelength lower than this is ultraviolet.

UV ranges from 100 nanometres to 400nm. UV is further divided into UV-A, UV-B and UV-C.
UV-C: ranges from 100nm – 280nm (germicidal)
UV-B: ranges from 280nm- 315nm (sunburn)
UV-A: ranges from 315nm – 400nm (blacklight)

We here are interested in the UV-C rays, also known as „short wave ultraviolet radiation“. UV-C`s germicidal properties have been known since the 1930s. They are used in labratories in order to destroy bacteria, mould and viruses. UV-C rays are able to penetrate the outer membrane of microbes and stop them from reproducing. The specific wavelength of 253,7 nm is known to break the DNA of pathogens.

In May 2007, two Dutch inventors, Arne Aiking and Frank Verheijen were granted an International Patent on a method of treating live plants and mushrooms against pathogens with UV-C light. In the past UV-C had only been used to sterilise things like air and water. The difference with proposing to use UV-C to fight pathogens on living plants is that you shouldn`t use any more than is necessary, otherwise there is a risk to health of the plant.

Mr. Aiking and Verheijens invention is a mobile UV-C lamp that travels up and down in commercial greenhouses. The light intensity of a UV-C germicidal light bulb is usually expressed in a term called „microwatts per square centimetre“. Mr. Aiking and Verheijen suggest a range between 2,500 and 150,000 mircrowatts of UV-C energy over a given 24 hour period.

E.g. A 100 Watt UV-C lamp will output approximately 14,000 microwatts of energy over a square centimetre, in one second, from a distance of two centimetres away. If we leave it there for one minute we have to multiply that figure by 60. (840,000 microwatts). Look at the following chart:
1cm 21,000 µW/cm2 UV output
2cm 14,000 µW/cm²
3cm 10,000 µW/cm²
4cm 8,000 µW/cm²
5cm 6,700 µW/cm²

100cm 360 µW/cm²

This shows that a second`s exposure at 1cm distance is roughly equivalent to a full minute`s exposure 1 meter away (360 x 60 = 21. 600µW/cm²).

We use the UV-C light to fight against powdery mildew in our plantation. Tests have shown that powdery mildew is killed when given a dose of 1720 µW of UV-C per square cm. For exemple if I took a 100 Watt UV-C lamp and positioned it two centimetres away from the mildew, I would need to switch on the UV-C lamp for just 1/10 of a second to kill it.

Spider mites could possibly also be effectively treated with UV-C but with amounts that are hundreds of times more compared to something like powdery mildew. We therefore use it only against powdery mildew.

The safest way to use UV-C on plants appears to be regular, smaller doses rather than a single, lager hit. We therefore use the UV-C light every day for a short time. The pathogen must be hit directly with the UV-C rays in order to be affected. If it is protected by a leaf, the UV-C will not be effective, because UV-C will not penetrate through leaves.

WARNINGS:
UV-C light has an intense burning effect on human skin and can quickly damage your eyes.
Protect your eyes with special eyeglasses
Don`t expose your skin to UV-C rays
The wrong amount of UV-C will damage your plant
This topic is part of one of our next episodes on FlowerfieldTV. We have just started the treatment of our plants with UV-C rays. At the moment we also use sulphur, because we don`t run the risk of getting powdery mildew. After that stage will treat our plants exclusively with UV-C ray. We will regularly report our experiences and tell you our improvements in This thread.

Finally I want to say thank you to Everest Fernandez, who provided a lot of information for this thread.
Excellent response and a lot of good information. You definitely make the point that UV-C is not to be used without a complete understanding of the handling and dosing of this spectrum. I generally agree with everything put forth but would like to point out some mischaracterizations regarding the way power and energy have been discussed for the purposes of using UV-C for plant sterilization.

Powdery mildew requires around 1800 u watts of uvc to kill the spore. On an 11 watt uvc bulb that means a quick once over with the lamp will kill all spores the light falls on.

The proper specification for a dose is total Energy per an area. This specification is given in uWatts which is Power (Energy/Time) not Energy and also lacks the Area it is applied to. The copy and paste is incorrect in that it is mixing up Power with Energy. My best guess is that the author intended this value to be 1800 uJoules/cm2.

Good daily short term use not only kills spores but actually helps the plant to develop thicker leaves which again helps to combat pathogens.

Uvc really is the way forward for desease control.

Here is a copy and paste from another site...
.........

Ultraviolt light (UV) occurs from the sun. The wavelength of UV is outside of our visible range. The lowest wavelength colour we can see is violet, hence the name for light with a wavelength lower than this is ultraviolet.

UV ranges from 100 nanometres to 400nm. UV is further divided into UV-A, UV-B and UV-C.
UV-C: ranges from 100nm – 280nm (germicidal)
UV-B: ranges from 280nm- 315nm (sunburn)
UV-A: ranges from 315nm – 400nm (blacklight)

We here are interested in the UV-C rays, also known as „short wave ultraviolet radiation“. UV-C`s germicidal properties have been known since the 1930s. They are used in labratories in order to destroy bacteria, mould and viruses. UV-C rays are able to penetrate the outer membrane of microbes and stop them from reproducing. The specific wavelength of 253,7 nm is known to break the DNA of pathogens.

Germicidal UV sterilization is optimal at 260nm and good results are generally achieved in the 240 to 280 nm range. What is special about 253.7nm is that it is very close to the 260nm optimal, but more important it is easily produced since it is the primary quantum emission for Mercury.

In May 2007, two Dutch inventors, Arne Aiking and Frank Verheijen were granted an International Patent on a method of treating live plants and mushrooms against pathogens with UV-C light. In the past UV-C had only been used to sterilise things like air and water. The difference with proposing to use UV-C to fight pathogens on living plants is that you shouldn`t use any more than is necessary, otherwise there is a risk to health of the plant.

Mr. Aiking and Verheijens invention is a mobile UV-C lamp that travels up and down in commercial greenhouses. The light intensity of a UV-C germicidal light bulb is usually expressed in a term called „microwatts per square centimetre“. Mr. Aiking and Verheijen suggest a range between 2,500 and 150,000 mircrowatts of UV-C energy over a given 24 hour period.

Once again they are mixing up Power and Energy, Watt or uWatt is a Power term which is a rate of Energy transfer (Watt = Joules/Sec). Joules is the Energy term generally associated with Watts (Joule = Watt x Sec). With the exception of the 100 Watt UV-C lamp all of the values given below should be changed from W (Watts) to J (Joules).

The easiest analogy to make to this difference between Power and Engergy is the way the Power Company charges us. We are most familiar with Power as the quantitative term for our electricity, but the power company charges us based on kWatt-Hours. A kWatt is 1000 Watts, but Watts is a Power measurement which is a Rate of Energy Transfer. To get Energy we must multiply this rate by the time for which it is applied, thus Energy = Power x Time. This is why the power company charges us based on kWatt-Hours, kWatt being the power term, Hours being time and the product is actual Energy (kWatt-Hour).


E.g. A 100 Watt UV-C lamp will output approximately 14,000 microwatts of energy over a square centimetre, in one second, from a distance of two centimetres away. If we leave it there for one minute we have to multiply that figure by 60. (840,000 microwatts). Look at the following chart:
1cm 21,000 µW/cm2 UV output
2cm 14,000 µW/cm²
3cm 10,000 µW/cm²
4cm 8,000 µW/cm²
5cm 6,700 µW/cm²

100cm 360 µW/cm²

This shows that a second`s exposure at 1cm distance is roughly equivalent to a full minute`s exposure 1 meter away (360 x 60 = 21. 600µW/cm²).

We use the UV-C light to fight against powdery mildew in our plantation. Tests have shown that powdery mildew is killed when given a dose of 1720 µW of UV-C per square cm. For exemple if I took a 100 Watt UV-C lamp and positioned it two centimetres away from the mildew, I would need to switch on the UV-C lamp for just 1/10 of a second to kill it.

Spider mites could possibly also be effectively treated with UV-C but with amounts that are hundreds of times more compared to something like powdery mildew. We therefore use it only against powdery mildew.

The safest way to use UV-C on plants appears to be regular, smaller doses rather than a single, lager hit. We therefore use the UV-C light every day for a short time. The pathogen must be hit directly with the UV-C rays in order to be affected. If it is protected by a leaf, the UV-C will not be effective, because UV-C will not penetrate through leaves.

WARNINGS:
UV-C light has an intense burning effect on human skin and can quickly damage your eyes.
Protect your eyes with special eyeglasses
Don`t expose your skin to UV-C rays
The wrong amount of UV-C will damage your plant
This topic is part of one of our next episodes on FlowerfieldTV. We have just started the treatment of our plants with UV-C rays. At the moment we also use sulphur, because we don`t run the risk of getting powdery mildew. After that stage will treat our plants exclusively with UV-C ray. We will regularly report our experiences and tell you our improvements in This thread.

As these warnings indicate, the use of UV-C is not for the uninitiated and should be applied very carefully.
 
Here is a link to an article on the subject: http://urbangardenmagazine.com/2009/08/ultra-violet-uvc-the-new-weapon-against-indoor-garden-pests/

I'm very interested in this subject, I'll be getting a light soon and testing it out. I'd love to know:
What exposure times kill mites?
Is there more information available on the leaf thickening effect? Does this increase plant health? Exposure times to achieve?
What brand and model of lamp are best suited to our application?
What is flowerfieldTV?

I'll report if I come across more info and about my results when I begin to experiment. I heard about this from a plant pathology guy, seems very promising.
 
Get yourself a plasma light, especially from gavita.. Its emits UV-C, alowing low amounts of UV-B to be passed threw the protecting glass. The plasma would in theory destroy PM for the life of the buld, so along with awesome light spectrums it fully eliminates PM.. Win, Win :)
 

theherbalizor

Premium Member
Supporter
1,414
48
Hmm, yes and no. The gavita LEP can does emit uvc if you remove the filtering glass from the reflector.

Test showed the uvc had to be removed as there were no distance that did nt burn plants. Also highly dangerous for the end user.

DO NOT REMOVE THE FILTER FROM THE LEP.
 
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43
It sounds like UV-C light like MANY other things we use in horticulture must be respected and used SAFELY. This holds true with almost everything we use. To much or used in the wrong manner can cause harm.
 
Hmm, yes and no. The gavita LEP can does emit uvc if you remove the filtering glass from the reflector.

Test showed the uvc had to be removed as there were no distance that did nt burn plants. Also highly dangerous for the end user.

DO NOT REMOVE THE FILTER FROM THE LEP.

If I'm understanding correctly you will not have an UVC unless you remove the filter. UVB does not have the same anti-fungal properties as UVC, and in fact because of the way it kills things- by damaging their dna, there is no way to have a light that is effective that doesn't also present a significant threat to human safety. I think this isn't going to be something that is safe to release to the public at large because there will always be the ability for people to really hurt themselves (or others).

That being said, a person aware of the risks and being careful could harness this to potentially great advantage. So what we need to know is, how much power does the light need to deliver, and what are the right techniques to achieve the effect we want?
 
Like with everything in this world if you use it in-correctly anything can cause harm. I use UV-C light all day at work for the last 27 yrs. because I am a welder and if you use the proper safety precautions then you should be perfectly fine from any harms. unless you are looking straight at the light without a filter lens or on your skin, then yes you will be harmed, but if you use the correct protection then their is no harm to your body. Do you think pesticides are safe that you spray on your plant then injesting it into your lungs? because the quickiest way to injest something into your body is by inhaling it into your lungs. if you say no the sprays are safe because the label says it is then don't ever complain about GMO foods or pesticides on your food.
 
J

Jalisco Kid

Guest
Much easier was to take care of your girls. In a small room or a ventilation shaft I can see its use. Going over a 6' girl to make sure you lit everything up and not yourself would seem to take the fun out of it. Too many people believe if they are not in pain,or smell something funky everything is ok. JK
 
I didn't read anybodies response so forgive me if this has been covered, but if by PM your referring to powdery mildew then don't over think or overstress it. cut off PM infested leaves and then sulfur vape during dark period. A few applications of that and you should be good, especially if you don't have to worry about anything other then your tent. The tent will confine everything nicely. and then turn off exhaust and fans also. Don't sulfur vape past week 6 of flowering.
 
The sulfur vapors change the pH on surface area and provides an environment which the mildew cannot grow. the lights sounded to complicated and dangerous to catch my attention lol. But like I said, just take it easy and don't stress it.
 
J

Jalisco Kid

Guest
Sulfur burns are ok in rooms where the plants are spread out. Sulfur rises and settles on the leafs,the leaves under leaves kinda get left out. I spray K silicate now as I know I can hit everything. I use sulfur burns heavy between cycles while running all my ventilation equipment. I would use sulfur second as most chemical products out there are just don't cut it.JK
 
Sulfur burns are ok in rooms where the plants are spread out. Sulfur rises and settles on the leafs,the leaves under leaves kinda get left out. I spray K silicate now as I know I can hit everything. I use sulfur burns heavy between cycles while running all my ventilation equipment. I would use sulfur second as most chemical products out there are just don't cut it.JK
How late in flower do you continue your KSil foliar sprays?
 
J

Jalisco Kid

Guest
It depends on the season and how lazy I am. I find it is more needed in the winter then summer. In some rooms the temp differential is too large. I stop somewhere around weeks 5-6 of 10. It is the buds size that makes me stop. having that on young buds is where it really works for me. I never have pm but I find it works for the grey mold in weeks 8-9. truthfully I have been stopping around week 4 as I have not had any problems for a while so I have foolishly dropped my defenses. But I am old and lazy and not a cash cropper. JK
 
J

Jalisco Kid

Guest
I just saw your video, those guys lost a lot of cred with me looking at those sad assed lolly-popped plants. I guess with a plant structure like that you might be able to hit 90% of the plant. The light would have to be hand held or on some prop to get into my trees. You sure are not going to hit anything worth while in my rooms with that system. I can see it work in large propagating warehouses with small plants.
Then what do you do once pm is inside the plant,destroy all the cells? This can be used in my rooms for maintenance in ventilation shafts or a lung room. To me it is too much like ozone which also works but the line is too fine between healthy plants and killing all the pathogens.Good luck with it. JK
 
They're exclusively a commercial cloning operation and garden store. Flowering isn't legal yet in Austria, but plants in veg are allowed. I think using it in AC ducts is a good idea.

When you say KSil works for grey mold, do you mean preventative or to keep visible mold from spreading?
 
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