Drowning in conflicting plant graphs - help! (LED)

Still trying to design my LED light through clear understanding and not just mimicking.

There is one photosynthetic response curve that shows yellow light has more effect than blue light and that green, while lower, is almost as useful.

Other articles say green light may stunt plant growth and that yellow is not much more useful (despite the huge success of HPS).

Then there is the photosynthesis action spectrum showing that violet/purple light (400nm) has the highest absorption peak followed by deep read at 670nm with a huge dip in green and yellow - yet almost all LED mfgs stress a huge red to blue ratio.

Then there is the chlorophyll absorption graphs with multiple peaks and lesser carotenoid absorption peaks. (Seems this may be due to invitro rather than adult plant testing).

Then there are articles stressing the importance of balanced and 'correct' spectrum (CMH) and others stressing sheer photonic output (as seems to be the case with HPS). Another case is where a standard fluoro outperformed a plant grow fluoro due to higher photonic output. (Pardon if that is the inaccurate scientific descriptor).

I have read and studied many hundreds of pages on the internet and at the local library and while I have gained some understanding am in some ways more confused than when I started.

Is this merely a case of totally different aspects of plant physiology (or different plants) being studied or is it a case of incomplete information?

Whats up?

I have grown with LEDs but I definitely dont know much about the science side. You mention the blue and deep red with mfgs stressing large red ratios... From what ive read the plants use more blue light in VEG and red light in FLOWER. We are all about the flowers (at least I am :stoned:) so a light that produces more reds than blues is what is best for flowering.

Also I know HIDs like an HPS give off a huge spectrum of light but the plants benefit mostly from the reds given off. Same thing with MH bulbs and vegging. So a graph depicting the spectrum output of an HPS will show all sorts of colors but you only need to focus on the reds and blues. Or so ive read...

I hope all those pages of LED stuff I read (and mostly forgot! lol) were correct so i dont give you misinformation.

Just trying to help in any way I can.

Plants need a full spectrum. For twenty years we have been depriving our plants of love we could give it. You dont see them using HPS in the cast research grows. it is a combination of induction (plasma) and high end led where certain plants thrive under certain wavelengths. The science is restricted so it is a test for us all. This is no bandwagon anymore and its probably time we started to publish all we can in regard to new lighting. Personally i will be growing under Plasma lighting with added leds, It will give me a total full spectrum like the sun on earth and on top of that i am ramping up on the blue and red, obviously vital for veg andflower. The plasma units are actually cheap in comparsion to generating the same light with LED.

Are you going to log the plasma grow?

I totally agree that all knowledge should be posted here for everyone to benefit from it.

Got any sites selling plasma stuff? Im always curious to see new tech.

mrnobody would you discuss your induction light a bit more. I've done some reading and understand that similar to LEDs, there are a range of manufacturers pumping out bulbs with varying spectrum output. Have you narrowed in on a manufacturer / distributor? What specs do you look for?

I live in the Uk and have a specialised supplier here I have been using for LEDS for the last couple of years. His new products have the LEd built into them RED/BLUe and then full spectrum white light. The most powerful model is 500watt but only draws 250 and is about 20 times brighter than a HPS 600watt. There are few suppliers around but i think in the states Lumatek is leading the way and there are a few grow logs around on other sites showing these in action.

I will be doing a Plasma log as I should have done with the two I am doing at the moment with an LED/HPS split. (all vegged in LED though) Four weeks away from finishing on 55 Armageddon that look stonking, and 2-3 weeks away on 100+ Lowryders, The AK48 looking ridiculous and certainly no lowryder!

I have spent all and everything on this setup so cant afford a new camera at the moment, hence no grow log. There are grainy photos on another link.

cheers

The most powerful model is 500watt but only draws 250 and is about 20 times brighter than a HPS 600watt.

Try to make sense. A 500 watt light draws a minimum of 500 watts.

Twenty times brighter? Do you just make stuff up? :wtf:

when you build your LED will you post up what you did. I am thinking of building one after summer. Start a build your own LED thread. Or I will. No, you do it. I am too shy.
peace. good luck with it.

i agree that plants need a full spectrum light. just because there are peaks at certain wavelengths doesn't mean that there is nothing else but those peaks. nothing beats the sun, and the sun encompasses the complete spectrum. the specific wavelengths were more a rush to market approach IMHO. white LEDs are more expensive than the others (again, i know you know your shit, just puttting it out there). and there's still the fact that they are really blue LEDs with a Yttrium Aluminum Garnet phosphor layer. but white LEDs are considered as covering the entire spectrum.

i think ones best bet with proceeding in the LED realm, would bo to make a lighting rig that had all possible wavelengths on the market with each having it's own dimming circuit. i'm not saying it's that easy or whatnot, but i do believe that that would be a great way to start. i think we still have a very narrow understanding of all the wavelengths and their relation to plants. not everything in a plant comes from two (or four) specific wavelengths, so two (or four) wavelengths are not the answer. again, all opinion here, and by no means an expert. let us know what you decided and i most definitely will be following along.


-shake

I second what headshake said.
They make some LED's with a dimming switch. I have only seen the ones with adjustable red and blue.

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Originally Posted by demoreal

when you build your LED will you post up what you did. I am thinking of building one after summer. Start a build your own LED thread. Or I will. No, you do it. I am too shy.
peace. good luck with it.

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Sure. Sharing is what it is all about.

"The most powerful model is 500watt but only draws 250 and is about 20 times brighter than a HPS 600watt."

Yea, no.

That's taking 2 watt diodes, PWM underdriving them to 1w to obtain a higher efficiency, but still output less than a dedicated full-power 1w module.

PWM = turn around and ignore it, you're about to get gypped for more equipment that does less. Those panels are PURE MARKETING and just to let you know NASA outright rejected any underdriven or even PWM overdriven panel.

I agree that the marketing is total bullshi&* but in all fairness any plants I have vegged under them and transferred to HPS are fat, many bud sites and full of resin. The proof is in the pudding and the smoke. There are hundreds of completed growdd with LED now some very very successful, some terrible. Just like with HPS or any other lighting medium. You can have the sun on your door but if you cant balance out air and water its pointless.

As for Plasma lights only drawing half the wattage to generate the same equivalvent wattage? How much does a HPS pull from the ballast? When you know that figure and when you know the figure then we can have a discussion. Just because something is 500watt it does not mean it uses 500 watts power! that bit should be basic science for anyone playing with currents!

The less aggro we can give each other on here the better. I am simply relaying information I was given by a reputable source. Admitantly he is trying to sell my his Plasma lighting but if its good enough for Chelsea Football CLub, Liverpool, Man Utd, Fulham and twenty more to grow their grass? I think its good enough for my plants. The sun on earth! Yes its going to involve some experimentation and dialling in but if you watch your plants they tell you everything you need to know!

Vegging is one thing, PWM will do fine there, but for a fully-LED grow, PWM is just not the way to go. If you're gonna get that kind of panel, you might as well put a proper 500w driver without PWM, pull the raw power from the panel, and just destroy a 1,000w HPS. There's no real point in trying to regulate the duty cycle in horticulture, sure there's a purpose for human vision (we're limited to about roughly 70-85 'frames per second') but to plants what matters is the overall umol output at a constant rate per unit of time. PWM won't allow that.

"500watt it does not mean it uses 500 watts power!"

Actually, yes, when something is rated as 500 watts, that means it draws 500 watts per hour, or .5kWh. It's not basic science, it's basic math and knowledge of the formula which gives that number. I build these panels for large-scale commercial horticulture operations, from Australia to Morocco. If you say it's 500 watts, I had better be able to plug in my kill-a-watt and it better register 500+w. If I see 325, I'm returning the panel. All of my other clients would do the exact same thing.

And even then, it's not the wattage that matters at all for growing lights, although the energy you use versus how much of the desired crop you produce is very important. It's the photosynthetic photon flux density. umol/m^2/s-1 is the primary concern for plants, with wavelength ratios being second place. Measuring by radiometric output is not helpful unless you have a ton of other backing numbers, or you can simply have the umol figure and be done with it.

"Admitantly he is trying to sell my his Plasma lighting but if its good enough for Chelsea Football CLub, Liverpool, Man Utd, Fulham and twenty more to grow their grass? I think its good enough for my plants."

Oh, so that's where those microwave induction sulphur plasma units I shipped a few months ago went. I heard they were going to be used in pitches.

That's right, I do those too. My actual professional title is Director of Research.

Oh well, they're out of my hands so what's said about them is no longer my concern.

But on a fair note, you'd get better performance out of a 15000K HQI Metal Halide lamp than you would my sulphur plasmas. Again, the high lumen rating is what makes it so powerful. In reality, the spectral output just isn't there, and the units are too heavy for my tastes especially as they get into higher wattage ranges (most of that bulk isn't electronics, it's a heatsink,) which is why I quit making them and moved to designing new things, like HID/Induction hybrids. HID light, fluorescent tube heat output. That's a couple years away still, we don't have strong enough diamagnetic materials to accomplish what's needed right now for re-focusing stray EMF back into a linear tube.

Targeted monochromatic is the way to go. As soon as they make QD phosphors for induction fluorescent and my new hybrid lighting, you can expect a 150w hybrid to smash a 150w LED unit. Pure focused spectral output peaks with natural trace outputs, at far higher photon flux densities. But, of course, that much light still means heat so no matter what ventilation is needed. Even LED panels claiming NO HEAT are BS. Room temp in my house, good airflow in the PC case, my temps in the case still shoot up to 85 from the LED panel. Thermodynamics is a pain, isn't she?

As you are the most knowledgable here, I have two more questions if I may.

1. I can find nothing in the science that suggests a 6 or 8 to 1 red/blue ratio. Is this just attempting to copy HPS/MH spectra or are there real studies that support this? On one advanced cannabis board (engineers not growers), the conclusions was a blue to red ratio of 1.5 to 1 is best, while the absorption graphs look like it should be closer to the inverse, but nothing as extreme as all of the popular LED lights.

2. As you stated, and I have come to the same theoretical conclusion, that it's the photosynthetic photon flux density that is most important.

Let's assume these mfg numbers are accurate for this discussion. If I have a white LED that outputs 100 lumens/watt and has a higher total PPFD than either a 75 lumen/watt red or blue LED, (sorry no spreadsheet) why would I not go with all white LEDs? The spectra is something roughly like 40% blue, 10% green, 20% yellow and 30% red. (Don't hold me to those numbers.)

Any light you can shed (no pun) on these topics would be greatly appreciated.

Thanks!

One more question for you, Khy. (Always one more. :) )

I was considering PWM so that I could save power for seedlings and early veg and use one light throughout the grow. During mid-late veg and flowering, PWM would not be used.

Is this OK or is it better to use the light full power for the whole grow and just raise it high up in the early stages so as not to shock seedlings - or just use another light source altogether such as CFL for the first few weeks?

As my space is small, a one light solution is best for me at this time.

BTW, I have a commercial 120w (1w LEDs) tri-color unit. While construction is very nice, the lumen output seems insufficient even for my 2' * 2' grow space based on my last grow.

Fair points it must be said and the level of information was very helpful but it would appear everybody has there say and believe me there are other professors, director of research etc people around. You didnt answer my question about a HPS 600watt. How much power does that use? Because if i rememer rightly it uses more than 600watt? Hence why digital balasts are claiming to use less watts? Or am I jsut mistaken as I am sure I can fetch the links?

And as I have said already we should be trying to recreate the sun? Full total spectrum. Plasma do this. Yes there are bulky models like Lumateks but there are also ones which are a lot smaller than a standard hps setup. There are grows dotted around that have been done, albeit badly, under Plasma and the results are great, even in a poor environment. Especially the plasma horticulatual light poles which strcitly speaking you could have standing right next to your plants therefore creating that light at canopy level i think we should be looking for. My aramgeddon under LEd veg hav no popcorn buds, they are dense nuggets right down to the soil, i have supplental led light horizntally streaming across my canopy level.

I am wanting to ditch HPS as soon as I can so am passionate about new lighting. Plasma seems the way forward with supplemental LED lighting.

Facts are as only as good as proven results. For twenty years we have been ignorant towards lighting and still that ignorance seems bliss.

Anyone else have views on Plasma or any links? What is about is scarce but fascinating.

Clive says let there be light, like the sun (From Echo)

I'm no director of research - far from it... but my limited understanding tells me that plants do not use the entire light spectrum. In fact, it uses quite limited amounts of white, yellow, orange and green. So an HPS that pumps out tons of "white" light (not to mention heat) is wildly inefficient. It is successful due to the high photon flux rate across the spectrum.

Khyber get's crazy props for his in depth knowledge and understanding. We need to thank him for the time he puts in here educating nOObs like myself. I'm happy to address my next question to The Director.

I've seen these lights LEDs with dimmers and I've wondered why you would use them. OK, with young seedlings you don't need to raise the light if you can dim it. And I guess you could tweek them to better mimic sprning / summer / fall lighting but really, the major factor is time phase (12/12 vs. 18/4) so once your seedlings are into veg wouldn't you just crank the LEDs all the way up and leave them there to maximize output / penetration?

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Originally Posted by bigsby

I'm no director of research - far from it... but my limited understanding tells me that plants do not use the entire light spectrum. In fact, it uses quite limited amounts of white, yellow, orange and green. So an HPS that pumps out tons of "white" light (not to mention heat) is wildly inefficient. It is successful due to the high photon flux rate across the spectrum.

Khyber get's crazy props for his in depth knowledge and understanding. We need to thank him for the time he puts in here educating nOObs like myself. I'm happy to address my next question to The Director.

I've seen these lights LEDs with dimmers and I've wondered why you would use them. OK, with young seedlings you don't need to raise the light if you can dim it. And I guess you could tweek them to better mimic sprning / summer / fall lighting but really, the major factor is time phase (12/12 vs. 18/4) so once your seedlings are into veg wouldn't you just crank the LEDs all the way up and leave them there to maximize output / penetration?

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i have thought the same thing...whats the point of having a dimmer :wtf:

and i am in the same boat...just a grower with keen interest in new tech lighting :D

We ain't growing orchids...

Does different wavelengths of light create different results. If you have too much blue light during flowering would it create a leafy plant? Would you want more red? Possibly more blue during stretch then dim it a bit. More red then blue at the end. I don't know.

You guys are right. If I owned a LED with a dimmer I would most likely just crank both up during flowering. There are people that use MH for flower?
The point of the dimmer would be to use different wavelength ratios depending what stage of growth you are in. The same reason people use a different light for veg and then one for flower.
Has anyone done a side by side with an MH and HPS for flower? Does the MH create more leafy growth?
This would be a reason for a dimmer.
If this reason exists. I have no idea.
I have heard people claim to much LED during flowering is not good? (I do not know if I believe that) but if it is true it is another reason to crank up a more beneficial wavelength and mellow out another. Kind of like what you do with nutrients.
These are some reasons a dimmer would be nice. If these reasons even exist. There could be more???? Or maybe a dimmer is an unnecessary idea...

I live in the hottest & driest part of the country and am unable to properly cool and humidify my closet due to circumstance, which is why I got interested in LEDs. CFLs work fine for me lumen -wise, but the heat is way too much. So if I could minimize the watts used until I really need them, it would be a plus.

"I'm no director of research - far from it... but my limited understanding tells me that plants do not use the entire light spectrum"

Of course they do if they can! Hence the reason why outdoor grown green alwasy tastes better. Most plants, although I am not sure about cannabis, although the point about plants is made, most plants when the reach a point of cell saturation with light and they can absorb no more evolve and grow new cells capable of absorbing the light. What we forget is that its thanks to Afgan Week to do have what we do today if my somewhat limited knoweldge serves me correct. Weed will grow and adapt, evolve, learn and suit the environment its in. So if you saturate it with full spectrum light and supplement with high end red for flowering and blue for veg like we know works the plants with naturally be healthier as we are getting closer to nature. is that not what we should be striving for. Less mono-cultures and more diversity and through evolution.

They actually think plants in this world was once purplr or red because retinol was that active componenet not chlorophyl. Makes you think and makes you realise how plants evolve.

Stick them under Plasma, supplemental LED dialled in to your spec and watch the results. Better, stickier green. Closer to nature. Its this we need to be discussing and trying out.

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Originally Posted by bigsby

I'm no director of research - far from it... but my limited understanding tells me that plants do not use the entire light spectrum. In fact, it uses quite limited amounts of white, yellow, orange and green. So an HPS that pumps out tons of "white" light (not to mention heat) is wildly inefficient. It is successful due to the high photon flux rate across the spectrum.

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white, or visible light is composed of red, orange, yellow, blue, green indigo and violet light (or wavelengths). the part of the electromagnetic spectrum that we see is from about 390nm-750nm. plants use all the wavelengths except for green, which they reflect, hence why plants look green to us.

Quote:

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Originally Posted by bigsby

I've seen these lights LEDs with dimmers and I've wondered why you would use them. OK, with young seedlings you don't need to raise the light if you can dim it. And I guess you could tweek them to better mimic sprning / summer / fall lighting but really, the major factor is time phase (12/12 vs. 18/4) so once your seedlings are into veg wouldn't you just crank the LEDs all the way up and leave them there to maximize output / penetration?

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the reason i suggested dimmers was because you would have independent control of all the wavelengths at your fingertips. you would be able to tweak the ratios of every wavelength (that are currently available).

i, also, by no means am an expert. just an avid reader with more questions.

i applaud all of you for pushing the envelope.


-shake

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Originally Posted by demoreal

Has anyone done a side by side with an MH and HPS for flower? Does the MH create more leafy growth?

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MH does promote more leafy growth, hence it's used for veg, and the red of an HPS mimics the fall (harvest) sun.

i have read a study, and although it doesn't relate to MH vs. HPS specifically, it is still interesting. two crops of MJ were grown, one at 4500ft elevation, the other at 9000ft. the crop at 4500ft had about 25% more yield, but the one at 9000ft had better trich production. i know this pertains more to UV than spectrum (although, UV is a spectrum, or a group of really). with that being said, blue light and light closer to the blue end of the spectrum is more powerful than light at the red end due to frequency (i believe).

good growing!


-shake

My first sentence was not as well formed as it could have been although if you had read a bit more closely you would have seen my point. Try this:

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I'm no director of research - far from it... but my limited understanding tells me that plants do not use the entire light spectrum equally. In fact, they use quite limited amounts of white, yellow, orange and green.

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The point being that plants do not need the same levels of white, yellow, orange or green as they do red and blue. They use almost no green spectrum (our plants are green because they reflect this light back rather than absorb it). A grow that benefits from direct sun light tells us nothing about their ability to absorption white, yellow, orange or green spectrum. That's just misplaced causality.

Thanks headshake, I knew that about white light and it occurred that I should up pack that but you did it for me.

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Originally Posted by RackitMan

As you are the most knowledgable here, I have two more questions if I may.

1. I can find nothing in the science that suggests a 6 or 8 to 1 red/blue ratio. Is this just attempting to copy HPS/MH spectra or are there real studies that support this? On one advanced cannabis board (engineers not growers), the conclusions was a blue to red ratio of 1.5 to 1 is best, while the absorption graphs look like it should be closer to the inverse, but nothing as extreme as all of the popular LED lights.

2. As you stated, and I have come to the same theoretical conclusion, that it's the photosynthetic photon flux density that is most important.

Let's assume these mfg numbers are accurate for this discussion. If I have a white LED that outputs 100 lumens/watt and has a higher total PPFD than either a 75 lumen/watt red or blue LED, (sorry no spreadsheet) why would I not go with all white LEDs? The spectra is something roughly like 40% blue, 10% green, 20% yellow and 30% red. (Don't hold me to those numbers.)

Any light you can shed (no pun) on these topics would be greatly appreciated.

Thanks!

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1. There is nothing to support the current red-dominant ratios being made, and in fact several other studies show that greater amounts of blue are needed for proper flowering and seed production and bulk fruiting. At best they emulate the light from an HPS (though they never hit the photon flux density the HPS outputs in the same peaks.) Most MH lamps will outperform typical LED panels with such crappy balance. As for which spectral peaks matter, that's a really, REALLY dependent question. It depends upon the plant species, sometimes varying wildly between individual strains. In most plants that are green/yellow in color, They'll tend to use the red and blue peaks, green and yellow tend to inhibit the growth process except for trace amounts. The plant is still absorbing *SOME* of that light, but the majority is reflected back to us. On the other hand, you take something like the 'Wandering Jew' or 'Creeping Jesus' plant, which is predominantly purple/blue in color, is typically found in shaded areas, so mostly green and yellow light filter through to it, and it takes maximum advantage of this. This plant will actually PREFER an abundance of green and yellow light, and unless one tailored an LED panel to accomodate for this, the best bet for this would be the HPS lamp.

Assuming the 100lux/w figure, I wouldn't go with the white LEDs mainly because they burn out faster than any other pure-color LED - phosphors are used to shift the light into other visible wavelengths. Added to that, again, depending upon the plant you're growing, some of that light will act as an inhibitor. Of course, given that particular type of LED doing such lux at such low green/yellow output, you'd be better off finding the single-color versions of that same bin diode and using that instead, as you'll be pumping maximum usable power to the plant that way. A lux figure won't usually help you, but if you've got that plus the output chart, you can figure out what's rolling from where, as you weigh the lux figure to the green wavelengths, and then you can see the relative higher outputs for the other usable colors. This is how I determined usability of non-LED growing lamps when no PPFD figures are available (Maybe two bulb makers on the entire plant for HID/Fluorescent actually include that figure.)

Would it be beneficial to have a LED light with adjustable angle to play with the photon flux density?

There are adjustable lens from 4 to 90 degrees for the higher wattage LEDs. Not sure how much power is absorbed by the lens.

"I'm no director of research - far from it... but my limited understanding tells me that plants do not use the entire light spectrum equally. In fact, they use quite limited amounts of white, yellow, orange and green"

Im glad you changed that statement. Plants use everything they can. So if we can offer a continues spectrum as full spectrum is jsut a marketing term, and dial in extra red and extra blue into the specs which my induction lighting guy can do then the plants are going to love it a lot more than standard and conventional grow methods. That is the inly point I am trying to get across that there is a better way and Id like to know what is the best.

Oh and from earlier a 600watt HPS draws about 650Watt from the ballast! (Heat wastage!)

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Originally Posted by mrnobody

Plants use everything they can.

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Exactly. Read what you just wrote. "Plants use every thing they CAN." MJ plants can NOT use a great deal of the yellow, orange or green spectra (although, yes, as you stated they use everything they CAN within those spectra). So there is no need to flood the grow room with vast quantities of spectra that they can NOT use. Doing so is simply inefficient. An efficient grow light will produce appropriate quantities of light within the spectra that the plant CAN use.

I'm not sure why you insist on arguing this point unless it is to give props to plasma technology which, judging from the article you posted, claims to produce vast quantities of light across all spectra. If those lights are proven and if they are produced at costs and efficiencies that are accessible, then great; we'll all be using them in a few years. Until then, those of us concerned with heat and other efficiencies will look elsewhere. Unless you have specs on a plasma light that you would like to share?

Based on the literature, I'm doubtful that such a light exists, yet. Take a look at the website of the company that aims to bring this technology to market (as cited in the article you posted) - PLASMA INTERNATIONAL - PLASMA LIGHT SYSTEMS. You will see that they have not yet reach the point of mass production. You will also learn that their grow results were achieved by manipulating the spectra coming out of the light with filters and by deploying supplemental lighting. Certainly promising and worth keeping an eye on but not yet ready for prime time.

FWIW I didn't change my statement. I modified it by adding one word to better reflect the point that I made in the rest of the post.

I agree with what you are saying. But a little of that light that has been lacking in the past can only be a good thing. I will have specs on the lights I am about to purchase shortly. Yes Plasma technolgy actually has only jsut been harnessed in Essex in England, there are newspaper articles from April 2010. Its all linked into Plasma international. I think the company was started some years ago and since they have not had a commercially viable product or patented product. Just because it is not in production does not mean it does not work. Just look at concept cars for an example of that.

I will be using induction lighting but dialled in specifically to my needs. I.e. heavy on blue for veg and red for flowering. Both rooms will have LED at horizontal canpoy level and supplental spot lighting. After smoking my first ever bud tonight i am convinced the extra light spectrums adds serious strength to the finished product. For an example the bottom bud i trimmed three days ago, jsut the one, dryed in a draw sort of ghetto style and smoked tonight. I am more stoned than i have been all year and its safe to say this year i have been surrounded by bud. It shouldnt have even been cropped. Its got 3-5 weeks left on the bottom, maybe more and still is a noticeably tripply, different kind of smoke very remanicent of very good coffee shop bud. Dont get me wrong I know my smoke and am surrounded by grade Blueberry. To say I am excited is an understatement, Photos will be up tomorrow for judging and help and advice.

My next flowering room will be 8ft by 8ft and will use 2 x 300watt induction lamps and about 2000watt of led lighting dotted around. I am using the 120watt rectangular units with more high red than blue. The ufos i use in veg as they are so obviously more blue, i also use them above mothers, They absolutely love it. To date I have not see one bad leaf on all of my plants. Everything looks more healthy than I see all day every day in these forums. I would be glad to hear from anybody playing with other lighting, with no traditional methods involved. Results, smoke, pictures?

More importantly my rooms will not show up from above and will be a considerable amount cooler therefore easier to control the climate. the copters are a constant pain in England, they hate us! Funny thing is that they cant actually see the lights, they see the heat and where the heat builds and exhausts. ADS sheeting helps but without renting or buying a thermal camera who knows and they are a touch pricey!

I'll be more than glad to see an induction light come on stream here. We've seen a lot of talk about them and I've read some disappointing reviews elsewhere but nothing based on implementation. They certainly are of interest. And of course, we all hope that the plasma concept lives up to the hype and makes it into production. I can not run HPS or MH due to my closed basement setup which lacks exterior ventilation which is why I have traveled down this road. That and I don't think I could leave my house with those incendiary devices running full tilt... an accident waiting to happen as far as I'm concerned. I look forward to the piccies!

"My next flowering room will be 8ft by 8ft and will use 2 x 300watt induction lamps and about 2000watt of led lighting dotted around."

That's well overkill for a room that size - you'd do just as well running 3 600w MH lamps and be done with it, IMHO.

"I'll be more than glad to see an induction light come on stream here."

Give me a short amount of time, I have my new prototype finished, it'll be on the way with my next sea freight shipment.

At the moment in my 4x 4 flowering room I have 5 600watt HPS. It probably is overkill but the plants love it. Real light saturation. My yields will be up, the strength will be up and the plants love it.

Once plants reach the stage where they can absorb so more light their cells evolve to ones that can. All plants do this apparently so perhaps the same can be applied to the magic green?

And what is overkill anyway?
Surely more light equals ore bud and more healthy plants. My temp is high, true but only in the mid eighties and the humidity is really low arond 20-30%. I have no mites, insects, mould, fungus or any bad leaves.

I have a pile of thirty HPS just sat here so it seems a shame to not use them. Ok I am now hampered by how much electricity I can atually put through the circuits in my house. With those 5 x 600 watt HPS i also have another 6 HPS 600watt downstairs with 1500 LED power at horizontal level. 100+ lowryders love it!

I use 100 watts of HPS a square foot. I am getting another light for the center but nothing over 150, that will make it around 137 watts a square foot.
187 is a bunch. How hot does it get in your grow room?

i am running my grow room at 85 with a humidity of 20-30. i was concerned with the heat but have good air circulation and lots of fresh air coming in. I have watched them intensely and added fans when the plants looked liked they needed them. I am not so dialled in on my lighting per ft/mtr yet, this being my first grow and having a big pile of HPS to play with I went for overkill, as many as i could get without messing with the climate too much. What i was taught is that you cant have too much light? It just changes the grow a little, watering, nutes etc. What I have allowed for is a lot of root space with my plants being potted in 20ltr compost bags, the roots look like tree roots and still they have not reached the bottom, jsut filling out the bag. As they grow though they pull more mosture from the soil, changing my watering. Plants like heat though. Especially Indicas where their genetics comes from hot, dry climates. As long as I am below ninety and can control fresh air I feel confident but with induction and LEd i will have more of a problem keeping the heat in I think.