# Theory on LEDs - Why they need CFLs to perform



## Syr (Aug 21, 2009)

So, I've been really thinking about this whole LED thing lately. Why are so many people having such different results? Why do the CFL + LED grows do better than the 100% LED grows?

My first thought was that the CFLs must be doing all the work, since I had seen so many bad grows that used only LED lights. But after comparing yield (grams per watt), I noticed that LED + CFL were also out performing CFLs by themselves, watt for watt.

So why are LEDs bad by themselves? Well, I got really high earlier and thought about it, and it actually started making sense. 

Think about plants in terms of what plants are, a living organism pre-wired to survive and thrive given the conditions. Their DNA has given them traits to detect and grow towards lights. That's why plants will always lean towards the light, even after you bend/pull/train them.

So, we know plants can at least sense light... not only that, they can sense WHERE the light comes from!!! That's how they can lean towards light. One of LED lights' biggest problems is plants stretching straight to the LED lamp, rather than bushing out, thus hurting yield. But why?

To explain this, I made a couple pictures in MS Paint (still kinda high, but bare with me, this is good stuff!). Notice the first picture, it shows the light spread emitted by both LED and CFL lights. Now pretend you are a plant, you are completely blind BUT you can FEEL light. If you want to grow towards the light, where are you going to grow? This is displayed by picture 2. Notice the arrows actually do mimic the pattern of growth seen from both types of lights, PLANTS GROW TOWARDS LIGHT. White light from HPS and CFL is emitted in every direction and fans out rapidly. HPS is simply more intense than CFLs.

If a plant feels light from everywhere, it'll grow everywhere; but, if it feels very intense light from a single source, it's going to grow to that source. That is why LEDs can claim 400w/600w equivalence during VEGETATIVE growth, the plant is so small, it is only going up anyways.

*(Continue on next post)*


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## Syr (Aug 21, 2009)

*...Continued*

*So what happens when CFLs and LEDs are used together? *
The spread of light from the CFLs make the plant bush more, creating more surface area to absorb light. Then, the intensity and spectrum specific light from the LED promotes extremely healthy and fairly rapid growth.

*Can LED+CFL out perform HPS?*
Well, the jury is actually still out on that one. There have been results that show yields as high as 1g dry bud per 1 watt used. I'm actually doing a LED+CFL grow myself right now and am, so far, fairly pleased with the progress. Right now, I'm going to say stick with HPS for big yield if you have the right area to grow and the right cooling to keep heat down.
*
When should I consider LED + CFL for my grow?*
If you have a relatively small area that you can't get very good ventalation to, this would be a situation in which this combo might be ideal. I'm still trying to see how close to HPS this setup can get. It's not equivilant yet, but if HPS is not an option, I believe this is the next best.

*
Hypothesis:*
So, I can't post a "theory" topic without posing a theory. I consider it's more of a hypothesis, rather than a theory, but here it is.

First, I want people to FORGET all the false claims, 90w ufo beats 400w hps blah blah blah. What about 90w ufo and 2x30w cfls vs a 150w hps? Or 300w LED with 3x 100w cfls vs a 600w HPS.

Now, I know LEDs are all about saving electricity, but I think that's horse shit. You can't get something for nothing. To grow something, you need to supply it with energy, no 90w fixture is going to supply a plant with as much energy as a 400w light. But, LED light is specially designed to use the most utilized spectrum of light for plants. So, is it a stretch to assume that 400w of LED/cfl might rival 400w hps with less heat generated?

It is my belief that when there is an ideal combination of both CFL and LED light, that this setup can either match or out-perform HPS lighting. Now, whether that is 1w LED per 1w CFL in a 50/50 setup, or is it 1/2w to 1w, or vise versa. There must be some ideal combination, the trick is figuring out whether it's more LED light, or more CFL light that makes the combination work.


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## SupraSPL (Aug 22, 2009)

Have you seen the LED lab thread on IC? They go in depth discussing theory and testing different wavelengths and are also conducting comparative tests. 

https://www.icmag.com/ic/showthread.php?t=108442&highlight=r/fr+ratio

Heres what I got from it so far (16 hours reading but only on page of 28/48!) If we can discover what exact spectra ranges are needed and at what ratio, custom LEDs could eventually be manufactured using the very high efficiency white LED technology that is being developed. These custom LEDs would have phosphors or quantum dots that output the perfect balance of spectra for flowering cannabis. If we can achieve this, LED will be able to outgrow HPS with a significant reduction in power consumed and a significant reduction in heat. Efficiency is increasing and the cost will come down. There is little doubt in my mind that we will get there.


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## Brick Top (Aug 22, 2009)

NASA has had tremendous success using LEDs both on earth and in space. The problem with the LEDs most herb growers experience is they purchase vastly inferior LEDs to what NASA uses, and purchase to few of them due to the expense and the results they get from them makes them believe LEDs are inferior lighting. 
&#12288;
Some years back I followed a thread on a now defunct herb growing site where someone purchased very high grade LEDs and his results were as or more impressive as I have ever seen from an indoor grow. He hung LED panels above his plants and ringed his plants with LED light bars on what I call portable posts and also had more portable posts with LED light bars on all four sides giving light in all directions between the plants. From top to bottom he had not only thick lush plants but also large thick firm heavy buds.
&#12288;
Like anything else you get what you pay for. If you purchase low quality LEDs or do not purchase enough of them to adequately do the job or if you just do not know how to place/use them your results will not be at all impressive but if you do the opposite you will be extremely happy with the results.


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## born2killspam (Aug 22, 2009)

Supra, when you go fucking around adding phosphors etc to LED then you kill the output efficiency.. And as for quantum dots, well I have a hunch you'll be waiting a long time for consumer products to employ that.. Its truly sad how far behind the physics engineering and marketing are..
There is alot of time for some new tech to come along, and render all this stuff obsolete before they improve LED tech sufficiently..


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## beeker74 (Aug 22, 2009)

Brick Top said:


> NASA has had tremendous success using LEDs both on earth and in space. The problem with the LEDs most herb growers experience is they purchase vastly inferior LEDs to what NASA uses, and purchase to few of them due to the expense and the results they get from them makes them believe LEDs are inferior lighting.
> &#12288;
> Some years back I followed a thread on a now defunct herb growing site where someone purchased very high grade LEDs and his results were as or more impressive as I have ever seen from an indoor grow. He hung LED panels above his plants and ringed his plants with LED light bars on what I call portable posts and also had more portable posts with LED light bars on all four sides giving light in all directions between the plants. From top to bottom he had not only thick lush plants but also large thick firm heavy buds.
> &#12288;
> Like anything else you get what you pay for. If you purchase low quality LEDs or do not purchase enough of them to adequately do the job or if you just do not know how to place/use them your results will not be at all impressive but if you do the opposite you will be extremely happy with the results.


 I hearya M8, I shudder everytime I see some new hopeful bust out a GLOW PANEL-ala e-bay.Ya wanna tellem, but you know it wont do any good.On the NASA thing, I read that someone actually bought the led set-up at Florida University, the one used for the NASA tests-wonder wot that lil bugga can do


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## beeker74 (Aug 22, 2009)

born2killspam said:


> Supra, when you go fucking around adding phosphors etc to LED then you kill the output efficiency.. And as for quantum dots, well I have a hunch you'll be waiting a long time for consumer products to employ that.. Its truly sad how far behind the physics engineering and marketing are..
> There is alot of time for some new tech to come along, and render all this stuff obsolete before they improve LED tech sufficiently..


 Whats your take on plasma sulfur M8.I dunno, those lil bulbs put out an incredible amount of light.


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## beeker74 (Aug 22, 2009)

http://www.youtube.com/watch?v=AXleNpqV11c I'm sure many of ya have seen this, but I still cant get over the sheer intensity from such a tiny point in space.


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## born2killspam (Aug 22, 2009)

I'm not sure about that one yet.. Reserving judgement..


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## beeker74 (Aug 22, 2009)

born2killspam said:


> I'm not sure about that one yet.. Reserving judgement..


saw a grow test in HT mag-but I'm sure you've also read the Jorge Cervantes led "test", so thats kinda soured my opinion of ole HT.They need sponsors after all eh?


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## born2killspam (Aug 22, 2009)

Actually I don't pay much attention to those mainstream guys/publications.. Any tidbit of usefulness they may have will eventually get repeated here.. Not much of my physics knowledge comes from HighTimes at all..


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## beeker74 (Aug 22, 2009)

born2killspam said:


> Actually I don't pay much attention to those mainstream guys/publications.. Any tidbit of usefulness they may have will eventually get repeated here.. Not much of my physics knowledge comes from HighTimes at all..


 LOL!! you mean there arent any tid-bits regarding the physical properties of the universe sandwiched in with LEGAL BUDS and bikini shots?I hear ya m8.


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## jeebuscheebus (Aug 22, 2009)

Everyone mounts thir lights in a stationery thir. My LED/CFL monstrosity has 90w LED and eight 32w 2700k CFL. 346 total watts on two plants. It is suspended by yoyo hangers and with the fans on they twist and move. I feel this helps to solve the issue of the plants growing towards a single point. 

My bud development is even like outdoor, not like most indoor.

I also use extensive LST to keep the plants from getting taller than 8-9 inches. We all know the limits of these lights penetration. Or maybe not judging by how most people use them.

Here are some pics. Three Cheese clones purchased from medical dispensary on 7-15. 4 leaf set on each at 5 inches tall.

Two weeks of 24-0 . I would add more light as the plants got bigger. The first week was just one 90w UFO.

12-12 started on 7-31. Here are pics from 8-13.


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## born2killspam (Aug 22, 2009)

I used to use the swaying light trick.. Worked pretty well..


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## Syr (Aug 24, 2009)

Here is Mazar-i-Sharif 35 days into flowering under LEDs and CFLs. I'm hoping they dense up a bit more, but after 35 days I'm pretty happy so far.


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## born2killspam (Aug 24, 2009)

How many days 12/12 did it take for those to pop pistils??


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## Syr (Aug 24, 2009)

About 9-10 days or so, I don't remember exactly, but just over a week. They didn't start really taking off till the last 2 weeks.


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