# The Positive Effect of Diffused versus Direct Light on Plant Health, Vigor and Yields



## Uncle Ben (Apr 9, 2011)

Many years ago when I started growing indoors I made sure to provide as much indirect or diffused lighting to all plant parts. I did this with careful placement of movable side reflecting panels. Little did I know at the time how important diffused light was regarding production, just made a botanical guess, I guess. I would use side reflecting panels painted with 3 coats of thinned Behr's Ultra White latex paint, AND, paint the plastic floor white too. ( Plastic mulches, white or red, are known to increase production in the field and in greenhouse trials.) I even went so far as to cut panels of such a width that they would fit into a corner, slightly angled up, like 75*. Now that's anal! My yields have always been very good and the growth rate excellent, so fast that I have no choice than to flower within 3-4 weeks of the seeds breaking the soil's surface once they germinate. 

Years later and after VERY extensive research and technical networking regarding glazing coverings choices for my new greenhouse, my choice of roofing material will be a diffused twinwall polycarbonate. Also, I have read studies from Cornell/Penn state regarding diffused versus direct and the tests always come to the same conclusion, diffused is best. Experimental studies show that crops with a high plant canopy and ornamental plants with a small canopy can utilize diffused light better than direct light. There are many diffusing products out there. Here's an example of one which addresses the benefits of diffused light over direct. http://www.polygal-northamerica.com/polymatte.php




> 8mm Polygal Polymatte&#8482; sheet provides 77% light transmission and 99% diffused light. Plants create food from light and the type of light they receive is important. Plants exposed to direct light (no diffusion) produce a majority of their food from the top leave facing the sun. These leaves do most of the work while the shaded leaves do very little work. Diffused light provides light to all leaves and all leaves are able to photosynthesize resulting in more food production and healthier, fuller plant development and less stress on the upper leaves.


Having said that, too many folks fail at lower canopy production, they do the lollipopping drills and such. They have not mastered light penetration. Reflected light can be your best choice, in fact using properly placed reflective panels a plant can easily receive 30% more light.

UB


----------



## DrFever (Apr 9, 2011)

I was shocked when i googled how much lumens does the sun produce ( 100,000 ) like 93 watts per Sq meter
I my self have have learned many things like even tho i run 1000 watt lights like 2 1/2 feet from each other, and plants seem like there beside a nuclear plant and grow crazy fast, it didnt matter how i did it i can not get lots of big buds on lower plant beeing canopy is covered my train of thought was pack as many plants in the room as u can even tho my yields are well over 1000 grams per watt thingy i believe i can achieve more by running less plants my indoor season is now over but my plans are to still run 10,000 watts but with no more then 40 plants


----------



## Zaehet Strife (Apr 9, 2011)

nice thread man! i do this kind of thing aswell except a little differently. i have a 4ft by 50ft roll of 2mil mylar, if you have some really thin wood or cardboard you can measure out a part of the growroom you want light reflected, cut out the wood/cardboard and tape/velcro/thumbtack the mylar to it, then set it up in your room.


----------



## WeedFreak78 (Apr 9, 2011)

Very cool post.I know this post is geared more to indirect lighting but I have a question about this which I asked in indoor growing but couldnt get a very clear answer. I got a bunch of 4ft 4 bulb T8's with the bumpy textured light diffuser panel in them(came out of a place that changed over to T5 fixtures). Im using 2 for seedlings right now, I was going to remove the panel to try to get more direct light to the plants but are you suggesting Im better off leaving that diffuser panel in?I checked with a (cheap) light meter and dont really see a difference with it or without just figure it has to be stopping some light.


----------



## Uncle Ben (Apr 9, 2011)

Zaehet Strife said:


> nice thread man! i do this kind of thing aswell except a little differently. i have a 4ft by 50ft roll of 2mil mylar, if you have some really thin wood or cardboard you can measure out a part of the growroom you want light reflected, cut out the wood/cardboard and tape/velcro/thumbtack the mylar to it, then set it up in your room.


I bypassed the mylar and just went with very large painted cardboard panels.



WeedFreak78 said:


> Very cool post.I know this post is geared more to indirect lighting but I have a question about this which I asked in indoor growing but couldnt get a very clear answer. I got a bunch of 4ft 4 bulb T8's with the bumpy textured light diffuser panel in them(came out of a place that changed over to T5 fixtures). Im using 2 for seedlings right now, I was going to remove the panel to try to get more direct light to the plants but are you suggesting Im better off leaving that diffuser panel in?I checked with a (cheap) light meter and dont really see a difference with it or without just figure it has to be stopping some light.


 Probably a moot point with a T8 but a diffuser might be important using a 1,000W HID.


----------



## Wolverine97 (Apr 9, 2011)

Good post. I use a Super Spreader for this very reason. Time and again I noticed that the plants in the hotspot bleached out and didn't produce as well as those receiving weaker direct, and more reflected light did better. I bought a better hood, put up diamond diffusion reflective stuff and added the super spreader and I haven't looked back.


----------



## SCARHOLE (Apr 10, 2011)

Sup Uncle Ben,
I dont want to be disrespetfull an dissagree with a ninja grower sutch as you.
But.......
Ive always thought different about Direct VS Diffuse VS specular lighting. 

Teach us more.



Uncle Ben said:


> Having said that, too many folks fail at lower canopy production, they do the lollipopping drills and such. They have not mastered light penetration. Reflected light can be your best choice, in fact using properly placed reflective panels a plant can easily receive 30% more light.
> 
> UB


 

I agree light reflected to the side of the plants is great. I practice this in my lil cabnet with the most reflective surface i could get free, mirrors.
They are angled for specular reflection right at my plants sides by kicking the bottom of the mirror out a few inches.
Its like recycling light IMHO.
(I dont have big enough lights to light burn them at my distances , 175 MH an 150HPS)



Here are a few thoughts / questions on this of mine..... Could you give me you view?



1.Anything inbetween your light an the plant will block some of the light so diffusers eat some of the plants light?

2.Isnt _Diffuse light or reflection_ weeker than _direct light or specular reflection _from the same source_?_ 

3.The more photons of light that hit my plant the better? (tell a critical point when cell start to die).
And I need all the light I can get in my little cab.
Do you think specular reflection from the mirrors would be better than Diffuse reflection off the white? (With my week hids, not sunlight lol.)

4.We use HIDs because we want Hight Intensity light so it can penetrate the canopy an give ALOT of light. 
Wouldnt diffusing HID light (or sunlight in greenhouse) be counter productive?

5.Is diffuse better because its a Lambert scatter an is more evenly distributed? 

6 If i flased you driving with a piece of white wood driving by nothing would happen.
If i flashed you with a mirror it would be BLINDING...
So how can diffuse white be more reflective an brighter (& deliver more photons for photosynthasis) than mirror or mylar? 


IDK?

Go easy on me for asking lol
Brick top got mad when I asked this stuff I think.
lol.

Any opinions would be apprciated....


----------



## sso (Apr 10, 2011)

i use cardboard panels as well, to reflect light on the sides, made do with a flat white ones.


----------



## Uncle Ben (Apr 10, 2011)

SCARHOLE said:


> (I dont have big enough lights to light burn them at my distances , 175 MH an 150HPS)
> 
> Here are a few thoughts / questions on this of mine..... Could you give me you view?
> 
> 1.Anything in between your light an the plant will block some of the light so diffusers eat some of the plants light?


There are trade-offs. There might be some light lossiness due to a diffuser. It's up to the grower to determine whether or not a diffuser would work for them, reason why I made the comment I did in the previous post. We're talking intense light from the sun or a 1,000W HID as opposed to soft light from a 175HID or a fluor. Click on the Polymatte twinwall specs. Normal clear twinwall is 80% LT with 20% diffusion. The Polymatte is 77% LT with 99% diffusion. It's a no brainer. Bonus is there is cooling effect due to the lower solar transmission and the diffusion. That's what I'm after.



> 2.Isnt _Diffuse light or reflection_ weeker than _direct light or specular reflection _from the same source_?_
> 
> 3.The more photons of light that hit my plant the better? (tell a critical point when cell start to die).
> And I need all the light I can get in my little cab.
> ...


Per my original post, diffused light from high lumen output sources reaches more plant parts, it excites more chloroplast material. Add in good reflecting panels and you've got a winner. If you look at page one of my topping method, you'll see how I sandwiched panels in the corners - 3rd photo.



> Brick top got mad when I asked this stuff I think.
> lol.
> 
> Any opinions would be apprciated....


Us ol pharts get impatient with those that appear to not do their homework. 

Good luck,
UB


----------



## SCARHOLE (Apr 10, 2011)

Thanks UB.
The new acrillic glazing stuff is dam cool.
Its going to take over the industy somday an glass window may be obsolete.
We sell it occasoinaly to folks for green houses huge sunroofs / Skylights and more..

We ger ours from Regal plastics , the boss is a tight ass so id bet they are about cheepest.lol
But many sell about the same suff.

Ps
After years lawn mowing I have noticed how Under the trampoline were plants get less light, _*they grow better*_.
Those cooking in mid summer sun grow slow.
I believe the cooling effect is very real when it realy hot.


----------



## QueefCollins (Apr 12, 2011)

Wow, interesting stuff. I use LED's which work great for the top 4-5 inches of canopy but end up having to lollipop since the light doesn't penetrate well. 

Do you have any advice I could employ to help fix that?


----------



## Uncle Ben (Apr 13, 2011)

QueefCollins said:


> Wow, interesting stuff. I use LED's which work great for the top 4-5 inches of canopy but end up having to lollipop since the light doesn't penetrate well.
> 
> Do you have any advice I could employ to help fix that?


Other than reading my first post, use a HID. I'm not singling you out, but if I can grow stocky buds down to the lower levels, you guys should be able to too.

UB


----------



## bobbypyn (Apr 13, 2011)

this info is dead on. outdoors in Texas in July, if you're under 50% shade cloth you're winning over direct sunlight, especially with indica and indica doms cuz they were evolved in much less intense light environs and can't handle the blazing Texas sun (yes, it burns hotter on Texas, don't ask me why, but it does) and I've always gone by the dictum that the sun produces as much light as 10 1K bulbs per sq meter. that's super overkill indoors under any circumstances that I've encountered. so 50% shadecloth is awesome for reduction & diffusion in extreme sunlight conditions.


----------



## Illumination (Apr 13, 2011)

QueefCollins said:


> So no helpful advice then. OK.



That was good advice..you just do not like the answer...the way to get canopy penetration is HID...get an hid source and use your leds as side lighting

Namaste'


----------



## Brick Top (Apr 13, 2011)

QueefCollins said:


> So no helpful advice then. OK.


You did receive helpful advice. You need to upgrade your lighting so it will be adequate to supply the lower portions of your plants with sufficient light. How you do it is up to you. Purchase a sufficient number of LEDs to use at different levels of your plants and surround them with LEDs or add a ton of CFLs at various levels or switch to HID lighting, a minimum of 400-watts, though higher would be better, as your main source of lighting and use your LED for supplemental lower lighting.


----------



## irieie (Apr 13, 2011)

if you are growing in a sea of green or scrog, then wouldnt the canopy be so thick that no light gets through to the bottom. then there would be no light to reflect onto the bottom branches.also because of the inverse square law, the amount of light decreases exponentially the farther away from the bulb that you get. so is it better to make your canopy as thick as possible and have the majority of your growth closer to the light where there is more lumen, or is it better to thin out the canopy to allow for light to reach the bottom branches which is not as many lumen? which way will give the best yield?


----------



## krok (Apr 13, 2011)

SCARHOLE said:


> Sup Uncle Ben,
> ...
> 
> I agree light reflected to the side of the plants is great. I practice this in my lil cabnet with the most reflective surface i could get free, *mirrors*.
> ...


Glass ABSORBS light!
What is a mirror? 
A mirror is glass (which absorb some light), put in front of a reflective surface (some metal). So the light has to go through the glass, which absorbs light, TWICE just to reflect the light back.

Ditch those mirrors, and get some Mylar.

Also, even if one had a 100% reflective surface, light would still fade exponentially.


----------



## Justin00 (Apr 14, 2011)

i have a 13 watt soft white CFL I'm flowering with but I'm not really getting good big colas, i have 28 plants under it and its about 6 feet away from the canopy so i can get an even light distribution. Uncle Ben, tell me want i can do to increase my yield and quality using "this light" with these plants.

but all jokes aside, this is a pretty interesting subject. got any pics of your green house UB?


----------



## Justin00 (Apr 14, 2011)

was just hoping it would make a few ppl smile is all, no need to get mad =(


----------



## Uncle Ben (Apr 14, 2011)

Justin00 said:


> i have a 13 watt soft white CFL I'm flowering with but I'm not really getting good big colas, i have 28 plants under it and its about 6 feet away from the canopy so i can get an even light distribution. Uncle Ben, tell me want i can do to increase my yield and quality using "this light" with these plants.
> 
> but all jokes aside, this is a pretty interesting subject. got any pics of your green house UB?


 Add another 13 watter or a 60W incandescent with an aluminum foil jerry made hood, shiny side out. You'll surely double your yields.

No pix of the greenhouse.

Not getting good yields happens to be the inverse of one's lack of experience and reliance on techno talk and theory.

UB


----------



## Illumination (Apr 14, 2011)

Uncle Ben said:


> Guess you know you're not able to receive PM's????


I sent you a pm UB about containers? When you have time?


Namaste'


----------



## Uncle Ben (Apr 14, 2011)

irieie said:


> no response to my previous post UB?


I took as a rhetorical question. Seems I don't have the "inverse" issues you guys have. If you're not getting good bud development at lower levels, beats the hell outta me.

UB


----------



## hazz (May 4, 2011)

Hey

Uncle Ben, what do you think of vertical lighting setups? Ive heard people pulling some good numbers with bare bulbs hanging down and plants wrapped around, giving good light distribution from top to lower leaves.

Thanks


----------



## Uncle Ben (May 4, 2011)

hazz said:


> Hey
> 
> Uncle Ben, what do you think of vertical lighting setups? Ive heard people pulling some good numbers with bare bulbs hanging down and plants wrapped around, giving good light distribution from top to lower leaves.
> 
> Thanks


Welcome to the forum. 

Vertical lighting? I don't buy into it. It's all about logistics. There are a dozen ways to get "good numbers". Just have to plan your garden and follow your plan.

Good luck,
UB


----------



## dannyboy602 (May 4, 2011)

^
^
Sup UB. I read a book by Jorge Cervantes recently and I read where he mentioned you. Man you do get around.
Also read Ed Rosenthal's book. Wow. Now that's some good info.


----------



## Murfy (May 4, 2011)

this is interesting to me-

i don't use hoods. i believe it takes alot of the good out of the light. i do notice that buds exposed to direct light grow faster, its limited to those flowers, lower ones will slow, but have increased potency. delivering sufficient levels of light to the BASE of the plant produces far more, as all flowers are producing at an equal rate, rather than top flowers goimg strong and the rest of the plant wispy.


----------



## mccumcumber (May 5, 2011)

Cutting the bottom growth in scrog is bad idea in my opinion.
The bottom growth does absolutely no harm to your plant if you give the nutrients the plant needs to support it. There are still a bunch of photons penetrating your canopy that can and will be absorbed by the lower foliage. Even the smallest opening in your canopy (believe me there is, photons are pretty fucking small) will provide light for all the lower foliage because of light's properties.
Knowing the way light works is pretty important to growing. 
http://quantumartandpoetry.blogspot.com/2009_03_01_archive.html
You don't really need to understand Einstein's theory and the other Quantum applications, just take a look at the double slit experiment. May I remind you that photons are subatomic particles, so they will find a hole and started spreading out rapidly in a wave. Think about water in a river going through a very thin area. Sure at that area it's super thin, but east of the super thin area (arbitrary example) the river thickens back out again. Should we dam up the area west of the thin slit... no! That's how you cause floods in one area and drought/chaos in another area. Just look at the dams in the Sierra Nevadas... did you know that there used to be lakes in bakersfield and the central valley.
http://www.history-map.com/picture/001/California-1800s-Late-Map.htm


----------



## Uncle Ben (May 6, 2011)

Murfy said:


> this is interesting to me-
> 
> i don't use hoods. i believe it takes alot of the good out of the light. i do notice that buds exposed to direct light grow faster, its limited to those flowers, lower ones will slow, but have increased potency. delivering sufficient levels of light to the BASE of the plant produces far more, as all flowers are producing at an equal rate, rather than top flowers goimg strong and the rest of the plant wispy.


I could write a book on this stuff (and about have)..... in short just gonna say that you need to understand how a HID emits light (the poles do not emit light), the dynamics of hoods regarding redirecting light, etc.

Lower plant area is receiving mostly FR light due to filtering effects of leaves, unless you have really good reflecting panels and use white "mulch".

UB


----------



## bud nugbong (May 6, 2011)

yea im big on the reflection of light...why let it go straight for 4 feet and do nothing...bounce that shit back and use it.

IMO its one of the most important things to do inside under lights.


----------



## My420 (May 8, 2011)

DrFever said:


> I was shocked when i googled how much lumens does the sun produce ( 100,000 ) like 93 watts per Sq meter
> I my self have have learned many things like even tho i run 1000 watt lights like 2 1/2 feet from each other, and plants seem like there beside a nuclear plant and grow crazy fast, it didnt matter how i did it i can not get lots of big buds on lower plant beeing canopy is covered my train of thought was pack as many plants in the room as u can even tho my yields are well over 1000 grams per watt thingy i believe i can achieve more by running less plants my indoor season is now over but my plans are to still run 10,000 watts but with no more then 40 plants


Am I reading this post right? 1000 grams per watt? Also your going to run 10k watts with 40 plants? Am I the only one who is asking myself WTF this dude is high on?


----------



## My420 (May 8, 2011)

mccumcumber said:


> Cutting the bottom growth in scrog is bad idea in my opinion.
> The bottom growth does absolutely no harm to your plant if you give the nutrients the plant needs to support it. There are still a bunch of photons penetrating your canopy that can and will be absorbed by the lower foliage. Even the smallest opening in your canopy (believe me there is, photons are pretty fucking small) will provide light for all the lower foliage because of light's properties.
> Knowing the way light works is pretty important to growing.
> http://quantumartandpoetry.blogspot.com/2009_03_01_archive.html
> ...


Interesting thought.. I disagree from experience about cutting the lower growth especially when talking about Scrog since the idea of that is to make a even thick canopy to get more bigger top buds. Why leave anything on that ( if done right you will get BARELY any light to the bottom stalks or buds) does not get good light and takes up nutrients? So what your saying is no matter how little of light it gets it will still produce as much as one on top of canopy or as good or just saying it will produce with any amount of tiny light? I think i am misunderstanding you on that comment because side by side comparison in the same environment different trays the ones that were we cut off everything that did not reach my canopy produced more. But I also learned that if you do not do this by week 2-2 and 1/2 at the latest before flower production it will not matter. The others produced nice tops but not as big as the others and have a lot of smaller not as dense pieces all over it and produced less. for example one plant same size cutting lower stems I got a HUGE top cola and the side branches that were on top of the canopy also were much bigger then the others and produced more. One plant non cut 2 oz 1.1 grams. Other plant produced 2 oz 18.3 grams dried. I got WAY less smaller pieces that you get from those tinny midget branches and got more production. Also have you tried both ways yourself? I have and I know it works for me.


----------



## SCARHOLE (May 8, 2011)

krok said:


> Glass ABSORBS light!
> What is a mirror?
> A mirror is glass (which absorb some light), put in front of a reflective surface (some metal). So the light has to go through the glass, which absorbs light, TWICE just to reflect the light back.
> 
> ...


 

Im Not a physics teacher or anything but....



Mirrors are Very reflective 95%+. so I guess the glass is eating 5% of the light, no problem there.

Outdoors or in Very intinse light Mirror may me dagerous with heat(use white for reflection).
But mirrors do not seen to dangerous indoors in little cabs like mine.

Ive noticed that... 
Distance dosent matter as much when reflecting with a mirror?
I can see the reflection of sun off a mirror for 100s an 100s of feet.
Specular reflection (mirrors flash ) dosent seem to follow inverse sqare law?
Any thought on this UB?


----------



## mccumcumber (May 8, 2011)

I'm pretty positive that mirrors reflect scattered light into one focused area... so that may not be too beneficial. I remember a while back learning some interesting equations involving mirrors, but that was two years ago unfortunately .



> *Interesting thought.. I disagree from experience about cutting the lower growth especially when talking about Scrog since the idea of that is to make a even thick canopy to get more bigger top buds. Why leave anything on that ( if done right you will get BARELY any light to the bottom stalks or buds) does not get good light and takes up nutrients? So what your saying is no matter how little of light it gets it will still produce as much as one on top of canopy or as good or just saying it will produce with any amount of tiny light? I think i am misunderstanding you on that comment because side by side comparison in the same environment different trays the ones that were we cut off everything that did not reach my canopy produced more. But I also learned that if you do not do this by week 2-2 and 1/2 at the latest before flower production it will not matter. The others produced nice tops but not as big as the others and have a lot of smaller not as dense pieces all over it and produced less. for example one plant same size cutting lower stems I got a HUGE top cola and the side branches that were on top of the canopy also were much bigger then the others and produced more. One plant non cut 2 oz 1.1 grams. Other plant produced 2 oz 18.3 grams dried. I got WAY less smaller pieces that you get from those tinny midget branches and got more production. Also have you tried both ways yourself? I have and I know it works for me. *


Ah, good questions. First off, when I first started growing, I used to cut off a little bit of lower growth. I thought that it was pretty fucking useless, and that it took away useful plant energy. I later changed my opinion after my grow last summer, when I just let the plants do there thing to see what would happen. It wasn't an official test with the same strain, so I didn't bother to compare yields, but I was very pleased with my final product, and have personally decided to keep as much growth on as possible. This is around 95% of the reason why I try to say that it is my opinion rather than fact, I have not done an actual compared test, so I cannot make a definitive statement, I just like the results that I happened to get. I never tried scrog till recently, and I am doing a run without cutting off the growth right now. Trying to test out my opinion. I just switched the cycle to 12/12, and the screen is being filled out nicely. And the lower fan leaves that seem to be in shade, are actually "in praying position" toward the sides of my diy grow box, so for the time being at least, I'm pretty sure they're still getting some light. It will be very interesting to see in about two weeks when my whole canopy is filled up and bud starts forming.

Secondly, what I'm saying is that even the tinniest holes in your scrog (and I mean tiny at the quantum level) will leak light out to the lower growth. There will be numerous (quantum level tiny) holes in your canopy, and because light is both a wave and a particle, it will slip through the holes and start distributing itself over all of the lower growth. The amount of light may be small, but you add that to diffused light that bounces around the grow room and will eventually make its way  out of your room or into some leaves. Being able to ensure that all of the light that does not go to your canopy goes somewhere will probably only help you. 

I'm very intrigued about your test results. It makes me think I'm missing something. I just don't understand how removing growth helps the plant. I don't quite know enough about plant horticulture (which I am really trying to learn more about... I'm taking as many botany and horticulture electives as possible before I graduate) to make a ratio that would determine the significance of cutting off lower growth. Your grow makes me think that the amounts of energy that the lower growth uses up is substantial. I may just have to cut off some of the lower growth on one of my plants this time around to see the results. I'm also doing a scrog outdoor this year (height is a very big issue for me outdoors for various reasons), so if I do indeed get better results pruning indoors then I'll try it on my scrog outdoors too.


----------



## Uncle Ben (May 9, 2011)

Mirrors are fine as is the shiny side of aluminum foil. May not be practical though....all depends on your set up.

Every green healthy plant part is capable of conducting photosynthesis.

UB


----------



## Zheol (May 9, 2011)

Orca grow flim diffuses light very well it seems and would be great for wraping a diy tent @11mil thickness I plan to get some to try when I can afford it the stuff it pricy $50 for only 4.5ftx25ft but the vids of demos make it seem worth it


----------



## VICTORYGARDENSHYDRO (May 9, 2011)

Zheol said:


> Orca grow flim diffuses light very well it seems and would be great for wraping a diy tent @11mil thickness I plan to get some to try when I can afford it the stuff it pricy $50 for only 4.5ftx25ft but the vids of demos make it seem worth it


 I saw this at a display at last years growla show, I have recommended it several times and all customers have come back with nothing but good things to say.It costs a little more then mylar, but the reflective properties are huge.


----------



## krok (May 16, 2011)

SCARHOLE said:


> Ive noticed that...
> Distance dosent matter as much when reflecting with a mirror?
> I can see the reflection of sun off a mirror for 100s an 100s of feet.
> Specular reflection (mirrors flash ) dosent seem to follow inverse sqare law?
> Any thought on this UB?


UB did not answer your question about specular reflection from mirrors, regarding the inverse square law.

Specular reflection is no exception, they will follow the inverse-square-law too. So if you are keeping the mirrors because of this belief, you should reconsider.

Mylar can be found for both specular and diffuse reflection, I would go for the diffuse one.

From wikipedia: "Reflection of light is either specular (mirror-like) or diffuse (*retaining the energy*, but losing the image) depending on the nature of the interface.".

So diffused light does not mean less light, from wikipedia:
"
Diffuse reflection is the reflection of light from a surface such that an incident ray is reflected at many angles rather than at just one angle as in the case of specular reflection. A diffuse reflecting surface will have _*equal luminance from all directions*_ in the hemisphere surrounding the surface.
"

To me, this means diffuse reflection is best.


----------



## Uncle Ben (May 16, 2011)

krok said:


> UB did not answer your question about specular reflection from mirrors, regarding the inverse square law.


That's because it is such an elementary concept that I didn't bother. FWIW, I retrofitted specular aluminum pieces into a gull wing shaped horizontal hood. 

Buy a light meter and remove all doubt.


----------



## allen bud (Jun 11, 2011)

Ive' been useing the flat white painted walls with my grows from the 80's till 2 years ago tried mylar did 1 grow and thew it away.lol..useing whate white walls again,I have alway felt that with the flat white and white floor, i have been useing the defused light for better lower branching development ,and you have helped me to add some proof to my own questions.I do not prune at all but UB toping ,super crop then lST thats it and i end up with big full happy plants.....and cudos for getting into jorge's "Bible",yup just rereading stuff,got jorge's latest book and BAM theres UB!!!!!(ok i know the book came out in 06 but..)
any way think ill see if i can work some angled panel in there to help even more!...peace...


----------



## endogarden (Jun 29, 2011)

Wolverine97 said:


> Good post. I use a Super Spreader for this very reason. Time and again I noticed that the plants in the hotspot bleached out and didn't produce as well as those receiving weaker direct, and more reflected light did better. I bought a better hood, put up diamond diffusion reflective stuff and added the super spreader and I haven't looked back.


I was interested in the Super Spreaders for this reason as well, but when I opened one up in the hydro store, it seemed like such a cheap POS, I couldn't imagine paying $35 bucks for it, let alone 4 of them total for the rest of my lights. Do they really work well? Anyone tried or seen a side by side? I just can't imagine that for all the talk of glass coated aluminum reflection blah blah, if you look at the actual device, it looks like a cheap CNC cut thin strip of aluminum, for $35. I was going to buy it, until I saw it, at which point the guy at the hydro store was also like, "yeah......" when I commented on how cheapo it appeared. Any thoughts?


----------



## Illumination (Jun 29, 2011)

endogarden said:


> I was interested in the Super Spreaders for this reason as well, but when I opened one up in the hydro store, it seemed like such a cheap POS, I couldn't imagine paying $35 bucks for it, let alone 4 of them total for the rest of my lights. Do they really work well? Anyone tried or seen a side by side? I just can't imagine that for all the talk of glass coated aluminum reflection blah blah, if you look at the actual device, it looks like a cheap CNC cut thin strip of aluminum, for $35. I was going to buy it, until I saw it, at which point the guy at the hydro store was also like, "yeah......" when I commented on how cheapo it appeared. Any thoughts?


I am considering using one in a vertical cooltube in the growroom now finally under construction. It will be serving the purpose of lower portion of the plants lighting so diffuse I feel is very important. So would a screen with smaller holes at 12" from the light source all the way around serve the dual purposes of diffusion of the light as well as preventing the bleaching or burning of the plants?

Namaste'


----------



## endogarden (Jun 30, 2011)

Illumination said:


> I am considering using one in a vertical cooltube in the growroom now finally under construction. It will be serving the purpose of lower portion of the plants lighting so diffuse I feel is very important. So would a screen with smaller holes at 12" from the light source all the way around serve the dual purposes of diffusion of the light as well as preventing the bleaching or burning of the plants?
> 
> Namaste'


Lumi, I'm betting if you could make or find a screen with a similar hole size and spacing as this:





then it would be virtually the same, or better. Though I'm not sure if the angle is a major part of it of not, seems you might get a similar effect with just using similar hole size and spacing in a screen.

Not sure about the bleaching, mine bleach when they are like 2-3" from the glass on my air-cooled radiant 8s with 600s. Supercropping branches, or tucking them under the trellis netting is how I try to prevent bleaching when my plants inevitably overgrow their low ceiling.


----------



## Wolverine97 (Jun 30, 2011)

endogarden said:


> I was interested in the Super Spreaders for this reason as well, but when I opened one up in the hydro store, it seemed like such a cheap POS, I couldn't imagine paying $35 bucks for it, let alone 4 of them total for the rest of my lights. Do they really work well? Anyone tried or seen a side by side? I just can't imagine that for all the talk of glass coated aluminum reflection blah blah, if you look at the actual device, it looks like a cheap CNC cut thin strip of aluminum, for $35. I was going to buy it, until I saw it, at which point the guy at the hydro store was also like, "yeah......" when I commented on how cheapo it appeared. Any thoughts?


Yeah, the price is the downside for sure. Since I started using it my total yield has increased by roughly 20% though, so for me it's $35 well spent. No more hot spots or bleaching leaves directly under the bulb. I like it.


----------



## Illumination (Jun 30, 2011)

Wolverine97 said:


> Yeah, the price is the downside for sure. Since I started using it my total yield has increased by roughly 20% though, so for me it's $35 well spent. No more hot spots or bleaching leaves directly under the bulb. I like it.


thank you that is exactly what I have been waiting to see...the opinion of someone who ACTUALLY USES it and the difference it made....definitely getting them for the vertical now...thanx wolv...big help for reals...and glad to see you at my new "home" as well

Namaste'


----------



## Root Source (Jun 30, 2011)

Been using one as well for the last few months. They definitely eliminate the hot spot and the girls have responded well. I would say it is worth the $35. I think the aluminum has some coating on it to help with the diffusion. It feels gritty.


----------



## Wolverine97 (Jun 30, 2011)

Illumination said:


> thank you that is exactly what I have been waiting to see...the opinion of someone who ACTUALLY USES it and the difference it made....definitely getting them for the vertical now...thanx wolv...big help for reals...and glad to see you at my new "home" as well
> 
> Namaste'


Combined with the proper reflector (I use the CAP XXX6), they work beautifully. I'm currently pulling between 1000-1350g from a 1kw with that setup. My light meter reads much closer to even throughout the canopy now, though not completely even. I'm probably going to try out an Adjust-a-Wing reflector with the spreader and compare the two, I'm just not sure when. Good luck with it lumi, and I'm happy to be there...


----------



## endogarden (Jun 30, 2011)

Wolverine97 said:


> Combined with the proper reflector (I use the CAP XXX6), they work beautifully. I'm currently pulling between 1000-1350g from a 1kw with that setup. My light meter reads much closer to even throughout the canopy now, though not completely even. I'm probably going to try out an Adjust-a-Wing reflector with the spreader and compare the two, I'm just not sure when. Good luck with it lumi, and I'm happy to be there...


Got damn! You pulled almost 3 elbows with 1 1k watt bulb??? I just harvested a little over 3.5 pounds under 4 600s (My electrical setup prevents using 4 1000s, plus I have 5 600w ballasts and 0 1kw ballasts),....so like .9 pounds a light, which I considered decent for the situation. How in the hell are you getting such fat yields? Good job too, btw, that's awesome.

P.S. This Sour Diesel I just smoked is amazing...


----------



## endogarden (Jul 9, 2011)

Well, I got a diffuser, we'll see how it works. I got the Equalizer also by sunlight supply, the 1000/600MH version, cuz that's what was in stock (should work the same in my estimation, this one is just tuned slightly different for 600 metal halide dome sized bulbs instead of penal shaped 600 hps bulbs).


----------



## Wolverine97 (Jul 10, 2011)

endogarden said:


> Got damn! You pulled almost 3 elbows with 1 1k watt bulb??? I just harvested a little over 3.5 pounds under 4 600s (My electrical setup prevents using 4 1000s, plus I have 5 600w ballasts and 0 1kw ballasts),....so like .9 pounds a light, which I considered decent for the situation. How in the hell are you getting such fat yields? Good job too, btw, that's awesome.
> 
> P.S. This Sour Diesel I just smoked is amazing...


Fine tuning man, fine tuning. I've been running the same strains for a bit over a year now, combined with SCROG and a really good soil food web is the answer. And that's with a light input of only around 40wpf. My last harvest was on the low end of that scale, I pulled around 1100 grams total dry manicured weight.


----------



## SOCALRP (Jul 11, 2011)

I had a really long, well thought out and witty post to make here that I just spent about 30 minutes writing, and my f-ing computer froze-- I literally looked to the heavens, pointed my finger and said: this is bullshit and you f-ing know it!!!  OK, I decompress and digress. This version is going to be way slimmed down.

First, huge respect and love for Uncle Ben and what he brings to the table (+ rep for sure). 

Second, big ups to everyone else keeping this thread going with different ideas.

I came to this community for the technical threads. I have plenty of experience growing, but I need to produce the best quality herb possible as a family member was recently diagnosed at an early age with an aggressive form of colon cancer.

Most everyone here is talking about diffusion of light emmitted from HID's. I would like to propose a different method of "diffusion" that is basically a direct hybrid. My idea comes not only from the knowledge that I have gleened here, but also from this thread:

https://www.rollitup.org/indoor-growing/358190-led-without-leds-my-first.html

In a rcdw/scrog setup I am thinking about putting a ring of lights at site level ( I am even thinking about running a couple broad spectrum T5's throughout the sites underneath the canopy), in an effort to encourage thick flowering below canopy level. Given how cool these lights run I think it's feasible, and would act to marry the benefits of both direct and diffuse lighting.

I know that this approach may seem that it's not in the spirit of this thread because you just end up packing your growing environment with so much light that it's akin to growing inside one big ass light bulb, but I would argue that the sun is kind of like the element in a light and earth would definitely be within it's "bulb". Anyways, I know I am a noob here, but I'm not going anywhere anytime soon and would love to discuss just about anything technical so we can all help each other learn.


----------



## Old Dog New tricks (Nov 17, 2016)

DrFever said:


> I was shocked when i googled how much lumens does the sun produce ( 100,000 ) like 93 watts per Sq meter
> I my self have have learned many things like even tho i run 1000 watt lights like 2 1/2 feet from each other, and plants seem like there beside a nuclear plant and grow crazy fast, it didnt matter how i did it i can not get lots of big buds on lower plant beeing canopy is covered my train of thought was pack as many plants in the room as u can even tho my yields are well over 1000 grams per watt thingy i believe i can achieve more by running less plants my indoor season is now over but my plans are to still run 10,000 watts but with no more then 40 plants
> 
> I know this is old, but a couple of misquotes should be corrected. First,93 watts per sq. meter doesn't equal 100,000 lumens. Second, definitely not producing 1000 grams per watt! That's 400,000 grams with a 400 watt bulb.
> ...


----------

