Is there such thing as "To much Light?

[dbfr3sh]

temps are good at plant height . use a 12 inch circulating fan in room and a 6 inch directed at the cool tube
. not sure thanks for ur input , it's appreciated . my plants are close to the source

does air flow directed at a cool tube change the radiant heat given off by the bulb? i dont think it does, could be wrong.

and to the punk whos trying to call my out on proven facts....dont really care about how u grow bro if you wanna utilize 25% of your light output have fun. but i have proven grows using the inverse square rule using t5s and i got .86gpw. 6in from souce is around 4X the light output...making my 20k lumens almost 80k

enjoy fag

 

[dbfr3sh]

i have a 4bulb t5 light enclosed in its standard reflector. its in a closet w/ no reflecting unless you count the fact that my closet is already off white. i utilized the fact that t5 have shitty penetration by growing wide plants. my plants were only 8-10in from bucket tops. 5 plants under 220w vegged for a month and flowered under the same light made a little less than 8oz. alot of people dont get that from there 400w HIDs in 95days sow to harvest.

the light is much denser at 6in than 12. if you take your hand and put it under ur light at 6 in and at 12 in your skin shouldnt be the same shade. go buy a meter and prove yourself wrong. so how come you can see a flash light from 20 feet away but it doesnt shine that far? LIGHT DEMINISHES OVER DISTANCE. your standard 400w hps can penetrate 3-4feet down but that light isnt as strong as 1-2 feet how you explain that? what if you have mylar on your walls does that mean your light travels forever?

your theory doesnt make any sense.

i got a better idea for you, line your walls w/ mirrors and then you can use 1 light w/out a reflector and you should be able to grow a 10' x 10' area no problem.

 

[dbfr3sh]

It depends on what you mean by the "radiant heat given off by the bulb".

Most glass transmits wavelengths below 3-4000nm, so a majority of the Infrared is going through the glass. 'Air' doesn't absorb or reflect these wavelengths either. So this IR hits the plants which do absorb them, probably because of all the water they are made of. Water absorbs pretty much everything over 1400nm, but we like our low humidity. Once we get over that inverse-square law thing being useless, everyone might think he DOES have too much light/ radiation.

didnt i say it was bc of radiant heat being too close to his bulb? yea i think i did.

 

[tree d]

There is a point of diminishing returns: You can only increase intensity by lowering the lights so much before the radiated heat is too much to be dissipated by the plant tops and they start to bleach, wilt, burn or stunt.

The old back of the hand test works for me. Hold it there at plant tips level for a minute if it gets hot, so will the tops.

My 600w cool tube has to be at least a foot away or I'll come home to crispy critters when I open the cab.

 

[Weezard]

So, we no fight, we measure.

So, we no fight, we measure.

So i took my light tester not knowing how it works but it shows on a scale from 0-2000. 6 inch's from the light it was ranging around 2000. At the top of my plants wich would be 36 inch's from the light it was ranging around 700. It is a crappy meter but it works fine and I hope this helps a little

Aloha Kushy,

Thanks for dat.
Beats lack of fact every time.

Made me whip out da ol' CT1330B lux meter.

In a 24" X 19", Reflectix lined space below a 10" array of 12. ~180 degree lambertian pattern, (no lenses) led emitters, I read 4,000 lux at 18" and 15,800 at 9".
(The inverse square law does not depend on 360 degree emission, just on a point source or a reasonable facsimile of a point source.)

But, (and here's where it gets interesting), at 4.5" I only get 28,000 lux.
I think I'm getting inside the "blending range" at 4.5"
At 9" and 18" the readings are fairly uniform.
At 4.5" they get "bumpy" and it's hard to hold the distance exactly. (minor variation being a larger percentage of the whole and all).

Mind you, we are not reading white light so the numbers do not equate to lumens etc.
I'm just using the lux meter to check relative intensity by relative distance.

And relax Smokin'.
Don't know where you got that printed reference, but air does, indeed absorb some light and does also reflect and scatter light. We are not dealing with one molecule at a time.
I only need a blue sky and a red sunset to prove that, brah.:smile:

Be good if some HID folks would whip out their yardsick and meters now, yah?

Play nice
Have fun
Weezard

 

[dbfr3sh]

Its really pretty simple, the photons have nowhere to spread out to, they cannot just go forever in any direction. They reflect off of surfaces until they are absorbed, the majority of which by the plants.

so in your theory a sealed closet would grow better plants then an open closet because the photons would just float away right? haha

so do u think that light bouncing off of walls reduces light?

http://hyperphysics.phy-astr.gsu.edu/HBASE/forces/isq.html#c4

here you go since you like pictures soo much

 

[h^2 O]

i dont know but if you could create a small nuclear reactor and get fuel you could grow ANYWHERE and have like 50 1K going without interruption for decades

 

[Mickymouse]

Only if you have more light than the sun.Where they grow outside.

 

[h^2 O]

Only if you have more light than the sun.Where they grow outside.

sun=130 watts per sq/foot

 

[Weezard]

My meter don't lie, an' niether do I.

My meter don't lie, an' niether do I.

I know no surfaces in a growroom reflect 100% of the the radiation hitting it, but of course a closet with four reflective walls is going to do better than one with three. All that light (photons) your seeing escape out of the closet could have been used as energy by the plant. and now its bouncing around the room being absorbed by surfaces which aren't highly reflective.

In this you are right 4 reflective surfaces are better than 3.
What you are missing about your chart is that a TUBE is not a SPHERE.


Think about it.


WeeZard

 

[Weezard]

Shine on you crazy diamond.

Shine on you crazy diamond.

I know no surfaces in a growroom reflect 100% of the the radiation hitting it, but of course a closet with four reflective walls is going to do better than one with three. All that light (photons) your seeing escape out of the closet could have been used as energy by the plant. and now its bouncing around the room being absorbed by surfaces which aren't highly reflective.

In a 24" X 19", Reflectix lined space below a 10" array of 12. ~180 degree lambertian pattern, (no lenses) led emitters, I read 4,000 lux at 18" and 15,800 at 9".
(The inverse square law does not depend on 360 degree emission, just on a point source or a reasonable facsimile of a point source.)

A sphere, actually.
If your light source is a tube, your milage will vary.

Even with no lenses the light doesnt spread out equally in all directions right away. That measurement at 9" wouldnt be constant throughout the 24"x19".
Yes, that is correct.
It is less than even at all distances that I can practically measure.
All measurements were taken dead center in a 4" area and are the highest readings found at each distance by holding the sensor to a yardstick and sweepin those 16 sq. in..
And I was almost as surprised as you must have been by the result because of the small, highly reflective space it is in.


The intensity at 18" would have been more constant, and you are trying to FILL the whole space with plants right? Even your saying the photons disappear, huh?

Dissapear? no!
Get absorbed and/or scattered? Yes, alla time.
Even refectix is only 97%.

(I would like to pop a flashbulb in a perfect vacuum, in a perfect cube fashioned from 100% reflective front surface mirrors. But the minute you try to detect your results... There goes that though experiment.)
Air is more than a mixture of gasses, got plenty dust, got plenty water vapor as well.

Don't know where you got that printed reference, but air does, indeed absorb some light and does also reflect and scatter light. We are not dealing with one molecule at a time.
I only need a blue sky and a red sunset to prove that, brah.:smile:

Air is made of lots of things, so of course it will have the same properties as water Huh?
also. And are you really saying rayleigh scattering happens at distance of a few feet. Even if it did, those blue photons aren't lost forever.

Don't recall having said that.
Lemme look, brb,

Nope, I didn't say that.
I was just saying that the little zen thing about air not refracting light was incorrect.
If it did not refract light we would not be able to "see" the sun after it has actually set.
Hell if different temperature air did not have a different refractive index we wouldn't see "shimmer water" on hot roads, or green flashes at sunset, or mirages.
All ya gotta do is read, and observe and think.
Air refracts, reflects and absorbs light.
Facts is facts.
Light is measured in units per square units and the law is the law. (inverse square law that is).
Keep reading, my friend, and if something don't seem right to you, devise an experiment and test it.

Aloha
Weezard

 

[Weezard]

We seem to be leapfrogging here.

W.

"One more time, THAT MEANS LIGHT SPREADS OUT, IT DOESNT DIMINISH AT SOME HUGE RATE.."

He's only right ya know.
If it can make a few million light years without breathing heavy, It's not gonna poop-out on the way to the dank.
It's all about areal spread.

W

 

[Weezard]

Close!

Close!

You are almost there, brah.

"twice the height doesnt mean 1/4 the lumens. Twice the area does!"

Think about that statement for a while.

Aloha,
W.

 

[magiccannabus]

yeah the inverse square law is BOLLOCKS! It assumes a bulb suspended in space with zero reflection. Think of a spot beam at a theatre for example. All the light is reflected in one direction and there is zero evidence of an inverse square law! Everyone who quotes the inverse square law as fact of physics hasn't done much independent thought on the subject!

I wish you'd do some more research on this subject before telling me I haven't done much independent thought on the matter. Just because you're using a reflector doesn't mean one of the most basic rules of thermodynamics stops being true. Your logical error I think is in assuming that the law states that the light actually magically disappears. That's not it at all. It spreads out. If you use reflective walls, it bounces it back. Even the light bouncing back spreads the exact same way, using the exact same physical laws. It just doesn't seem like it since the ray forms overlap each other creating a higher photonic flux.

 

[magiccannabus]

"The individual air molecules are very small. They are so small in fact, that they are hundreds of times smaller than the wavelength of the visible light. Because of this we can never see an image of air molecules with visible light."

"So the fact that we can not see air means that the molecules in the air do not absorb light in the range that we can see, nor does it refract light."

While air refracts very little light, it does interfere with it compared to light in a vacuum, which of course means that the medium is capable of refraction. That's assuming you have perfectly clean air(and remember air is composed of dozens of elements). In truth, even in a fairly clean house each cubic inch of air has an enormous number of floating objects in it. Dust, dust mites, ashes, pollen, virii, bacteria, water, etc.. These things also interact with the light, making the refraction much greater than clean air.

 

[RockyMountainHi]

you two either need to get a room or get a life.

 

[Kushy]

I think I have learned alot from everyone. I really didnt think it would get this much response but I guess with out light you wouldnt have life. I say who cares about how far or how close lights are to your plants. We should be lucky we even can grow it. Let alone smoke it. Our world is just amazing. Thanks for all your input and help.

 

[Weezard]

Concise and to the point.

Concise and to the point.

Just because you're using a reflector doesn't mean one of the most basic rules of thermodynamics stops being true. Your logical error I think is in assuming that the law states that the light actually magically disappears. That's not it at all. It spreads out. If you use reflective walls, it bounces it back. Even the light bouncing back spreads the exact same way, using the exact same physical laws.


Both posts, spot on!
Never judge a player by his avatar.

Mahalo MC,
Clearly said, it's the spread.

Aloha,
WeeZard

 

[Weezard]

Aloha Kush

Aloha Kush

I think I have learned alot from everyone. I really didnt think it would get this much response but I guess with out light you wouldnt have life. I say who cares about how far or how close lights are to your plants. We should be lucky we even can grow it. Let alone smoke it. Our world is just amazing. Thanks for all your input and help.

Thanks for startin' this discussion.
Everybody learned something.

Mahalo nui
Weezard

Oh, yeah, to answer the original question.
Yes!

W.

 

[scaramanga]

If you have too much light you can get "light bleaching". I've only seen it once personally. It was a 1k in an area of about 2/3 of a sq meter; about 140 watts/sq ft.

Only on a Cannabis forum would you have people arguing that an established law of physics doesn't apply to them.