Thinking about using a 150w HPS? Don't bother- Here's why...

Discussion in 'Lighting' started by CFLweasel, Jan 14, 2009.

  1. a wah wee woh +Rep
     
  2. As you know, when you buy a cfl bulb you will be provided with a little information, but not much to work with...

    First off, the bulb will have a name. "cool white" "daylight" "halogen white" "warm white" etc. Then if you're lucky, they will provide a number with a capital "K" at the end of it. Examples: 2700K, 3000K, 6500K etc

    What we want to pay attention to is the number, if provided... Now I'll get into explaining what it means.

    First the K means kelvin, as in degrees kelvin (like celsius or farenheight). This is part of a slightly complicated comparison method that is based on human eyesight. Notice I said human eyesight, and not actual frequencies. It is this important difference that makes this rating system difficult to apply directly to plant growth... More about that later, back to the science...

    So, why would the color of a lightbulb be expressed as a ridiculouasly hot temperature? Here is why. There is something in the scientific world called A "black-body radiator." For simplicity we'll use a block of carbon graphite as an example. If you had a lab and a very intense heat source, and you started to heat that block of carbon graphite up to intense temperatures, you would notice that it will start to glow. Just like you heat metal and it gets cherry red, but different. Everything that absorbs energy will eventually give some of that energy back off. Just like when you get sunburnt your skin feels warm... You absorb light energy and re-radiate it as heat... In this case, the carbon graphite block absorbs heat energy and at some point begins ro re-radiate some of that energy back off as visible light energy...

    As the temperature of the carbon graphite rises, the color of the visible light will change. At about 2700 degrees Kelvin, the block will be giving off an orange light. As the temperature rises, the color of the visible light will shift down the rainbow through shades of violet and as it arrives at 6500 degrees kelvin, the light given off will appear to be a blue color.

    The problem here is that these colors are based on what the human eye sees, not what is actually there. Lets say for example you buy a 2700K "warm white" CFL. What the manufacturer is actually trying to say to you is this: When you turn this light bulb on, the color of the light you see with your human eyes, will appear to your human eyes to be the same color orange-y white that your would perceive with your human eyes if you heated a piece of carbon graphite up to 2700 degrees Kelvin and a lab and stared at the color of light it started giving off at that temperature.

    NEXT: why this figure isn't as helpful to us as we'd like it to be...
     
  3. As I said before, the Kelvin color temperature system isn't as helpful as we'd like it to be for growing purposes.

    Let's stop for a moment and think about what color is in the first place... In art class we learn that it depends- with paint black is the presence of all color and white is the absence of color. With light we learned that it workes the other way around- white is the presence of all color, and black is the absence of all color. Therefore, by transition it is fair to say that unless we are examining some sort of "pure light source", the light and colors we see are actually a mix.

    Sadly The same is true of my precious CFL's. This is why it is so tough to just "pick the right ones". In order to determine the "right light" we need to understand how plants use light in the firsat place...

    Plants could care less about color temperature of your lights. Like we established earlier, plants need to be provided with specific frequencies (not colors) of light in order to correctly use the light for plant growth purposes. Again, like we said, color is a mix, and the color temperature of a CFL only tells us what that particular manufacturers mix ends up looking like to our human eyes in the end. It is important to note that none of these provided statistics will in any way ever give us enough information needed to determine exactly what the mix is... It only gives us clues to head in the right direction...

    Another thing to note is that lumens won't help either... Lumens and lux are different ways of measuring the relative intensity of a light source, and again don't provide us with any useful information to help determine how much of that intense light is useful for plant growth.

    NEXT: Other, more useful ways of measuring and describing light
     
  4. #44 CFLweasel, Nov 12, 2009
    Last edited by a moderator: Nov 12, 2009
    Okay, so in my last post I tried my best to explain why Kelvin color temperature is almost useless because it describes what te human eye can see and not what's really there...

    To be more specific, and a little crude in my word selection the "real" way of measuring light is in nanometers. Light is a wave, so naturally the most sensible way to measure it is by expressing it's "wavelength" (the distance between the two peaks of the waveform). This figure is expressed in nanometers because the meter is the standard of measure for the metric system... See this nasa page for supporting info http://eosweb.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html

    If you look at the diagram I borrowed from their page (my taxes paid them to come up with this data so I hope they don't mind me using it here and giving them credit) You'll see the entire electromagnetic spectrum. The sun produces and gives off a mix of ALL of these frequencies...

    The human eye can only see the visible light spectrum, which is at the center of the chart... These frequencies of light are between about 400nm and 700nm (nanometers). What this means is that when the distance between the peaks of the electromagnetic wave are about 400 nanometers apart, the wave will begin to become visible to the human eye as a violet colored light. Waves that are close to 400nm but not quite, are basically "more violet than violet", or in otherwords still really close to violet but not visible to humans. This is where the term "ultraviolet" comes from.

    The same is true for the other side of the spectrum... As the peak-to-peak distance between the waves increases, the color of the light goes up the rainbow toward red. at 700nm, we experience the end of the visible light spectrum. Light that slightly exceeds this range is sometimes called "redder than red" because it's still close but we can't see it... That's why it is called infrared light...

    I'll post more soon, but I'm starting to fall asleep at the wheel here...
     

    Attached Files:

  5. Like we said before... the light we see from a lamp, regardless of the type, is a mix. Lights that are intended for home use are sold based on a kelvin temperature equivalent system. This is fine for home use because the kelvin standard is based on what the human eye sees, and typically CFL lights are used for human eyesight related purposes, so this works fine.

    The reason this doesn't work fine for plant growing purposes is because plants are picky about exact frequencies, not colors... Just like when you take a paint sample to have it matched at homedepot or something, the paints look the same, but technically aren't. The same is true of lights, just because two diffferent lights are rated at 2700K only means that they both look the same to your eyes. In the realm of science, the composition of each light is likely different.

    Light used for any sort of scientific purpose needs to be more precise. Scientists don't care about what their human eyes perceive, they care about what is actually there. They care about measurable, quantifiable, replicatable results. For that reason, scientists measure light in nanometers... Take lasers for example- measured in nanometers...

    So the next step is "examining the mix." To do this we will need a document called a spectral outtput chart/graph/plot/whateveryouwannacallit... I borrowed one from here What Wavelength Goes With a Color?and attatched it below.

    First of all, please note that this is a sample chart from a high pressure sodium bulb. Every light will be a little different. You should assume that this graph below is for demonstrational purposes only, and as such only really exactly matches one bulb out there somewhere, although the plotted curve is probably very similar to other HPS bulbs...

    Anyway here's the broken down version of what's going on with the chart below... Somewhere in a lab, someone put a light bulb into a very expensive machine that measures light. At some point the computerized machine spit out this chart. It looks tougher than it is... Here is what it is trying to tell us:

    Hi. I'm a graph of the spectral composition of your light. You know light is a mixture of lots of different frequencies, so I came up with this cool graph to try to explain to you how much of each frequency you've got in there that's making the color you see.

    As you look at the chart, the horizontal axis represents the frequencies of light, while the peaks represent the intensities of those specific frequencies which are mixing together to make the color you see.

    NEXT: now that we know how to quantify how much of each frequency our bulb emits, how do we apply that information to our growing advantage?
     

    Attached Files:

  6. look you guys are putting way too much thinking into efficency. i primarly use cfl's mostly 105 watt with6000 lumens output they cost me about 60 dollars shipped for 2. now they will produce 12000 lumens at 210watts usage. but consider this these bulbs dont come with reflector so you already are loosing precious lumens. now i recently bought a 150watt hps set up from htg for 69.99 plus 14 shipping. read the manual uses 150watts true. external ballast. this unit puts out 16000 lumens. except it comes with reflector to focus all your lumens on plants. cfl's do not emit there light from tips. therefore any side not facing plants is a loss of lumens. now you are using many small cfl's think about how many lumens you lost if only one side is exposed for plants you lost almost 50% of your usable lumen output. like i said i still use cfl's mostly so i am not knocking them. it's just that you guys are doing so much work on this and my point has not been taken into account. hope this helps
     
  7. I like the fact that a 150 hps has one plug and is self contained...You have to pretty much make a fixture for the cfls to work. I guess in my opinion, it all comes down to how easy it is to grow plants....With 150 hps you hang it and plug it into a timer. Hell of alot more time consuming with 10 little cfls

    Also everybody is talking about the price of cfls/watt..But I did not see anybody add the cost of the splitters, light fixtures etc....

    Once again I just think the hps is just easier!!!
     
  8. I finally got around to including a halfway decent looking chart of the color temperature concept I've tried to explain... Remember: this chart was made by a lighting company to confuse your decision about buying bulbs. Although the chart has a rainbow splashed on it, and some fancy diagrams telling you where a handful of different lights weigh in, without a spectral chart the color temperature alone isn't necessarily very helpful.

    These types of charts are basically trying to spoon feed you their take on why to buy the bulbs. The sales pitch is simple and probably sounds like this:

    "Plants like blue light for vegging and red light for flowering. Look at our cute chart... See how red our flowering lights are rated at? See how blue our vegging lights rank on our chart? Can we have your money now?"

    Anyway, the chart is a good example of the scale anyway...
     

    Attached Files:

  9. So if you're still paying any attention at all, I've probably made your head spin with my whining about how I've realized the kelvin temperature system for measuring CFL's (and many other light types) is nearly useless for growing purposes...

    Anyway, this led me to this new rant about which light frequencies plants require to grow with the greatest vigor... Let me start by saying that this question I am still trying to find a convincing answer to myself... I don't claim to be an expert but I'm here to share what I've learned and read about along the way...

    So from what I've gathered, the answer to this question is still largely in debate. I'm guessing both in the forums and in the commercial world, people are still trying to find the answer to this question as near as I can tell... I think that lighting companies, both HID and LED and FLUORO alike are all somewhat bullsh*tting you on the specs and performance of their gear... As for the LED growers of this current time period- we are truly pioneers in an area of growing that had been largely undocumented and un-experimented with...

    As I remember it- during the days of the "original led ufo" (remember the one on the cover of hightimes mag where they were growing a strain called "LA confidential"?) from prosource... Anyways, at that time ProSource said that they felt the best color red for plant growth was 630 Nanometers... The LED UFO's they made to these specifications performed well during vegetation, but did not perform well during flowering periods. They now market a so-called "second generation" UFO light which uses 660 Nanometer LED's for the red spectrum... Supposedly these models perform better for flowering.

    Some companies have implied that companies like prosource and their competitors knew that the lights they were selling weren't well suited for plant growth, but the wrong frequencies were used for first generation models because they used cheaper, off the shelf LEDs intended for traffic lights and weren't out of frequency too far.

    I'm not here to slander any company, and for the record rumpleforeskin is currently doing a review for prosource, so we'll see how that goes.... But- this is a good example of how the LED scene is evolving before us... People are arguing about frequencies and such and people are pointing the liar finger at each other, but in the end the industry is moving forward, and without competition, that wouldn't happen...
     
  10. Here's another chart of colors and nanometers that I found somewhere... I'm not sure if it 's accurate but if in doubt, I'd trust the one provided by NASA of course...
     

    Attached Files:

  11. Enclosed is a chart I borrowed from another thread off site... For citation purposes the link is here: http://icmag.com/ic/showthread..php?t=105515

    I'll Explain the chart more in detail in the following post. Just the chart for now...
     

    Attached Files:

  12. As you can see, the chart I posted is actually two charts...

    The first chart shows how the plant needs to satisfy two different sets of light requirements for the production of chlorophyll-A and chlorophyll-B... If you look, the chart is trying to tell you that the chlorophyll-A receptors in the plant absorb red and dark bluish light, and chlorophyll-B receptors in the plant absorb orangish and light bluish light.

    The "carotenoids" are alsso listed on the first chart. From what I have read, the "carotenoids" are kind of like sunblock for the plant... If you look at the curve for their absorption rates, they only respond to the blue side of the spectrum... I read that plants can get burned from getting too much light in this spectrum, so the carotenoids absorb some of this extra light almost like a sunblock... My research also suggests that although the "carotenoids" are not involved in chlorophyll production, it is still important to stimulate them for vigorous plant growth...


    Now the second chart- the second chart, near as I can tell, is basically the best average of the three waves in the first graph. The basic implication here is that if you can get a light source with a spectral chart that closely matches this wave, then the closer the matvch, the better...
     
  13. Appreciate the info and research but i agree that youre overthinking this. These bulbs will lose 40% of their output inside 6 months. Square pinset, linear pinset, screw-in, all of them. Ive ran the CFL bulbs in aquarium applications since they came on the market and effeciency dollar wise (the only reason we try to be effeceint) there is no comparison to HID. You will be buying CFL bulbs sooner than HID or your results will suffer compared to the original HID. While HID loses output as well, its not nearly as dramatic as CFL.

    Couple that with the fact that the vast majority of CFL users are using screw-in and not pinset bulbs, (pinset bulbs generally run paralell to eachother as opposed to spiraling, which traps light), and theyre usually reflectorless meaning even more lost light, and the CFL effeciency myth is busted. Youre only shooting yourself in the foot.

    Do note these are my experiances personally and these are my results. Not manufactuer claims or what some website says.

    Buck up and burn the extra 49 watts. Your results will thank you for it as well as your wallet.

    Sorry for my shitty spelling but you get my drift.
     
  14. I like a lot of the info in this post.

    I've been vegging with CFLs for a while now and I love it. Not only do CFLs generally do a good job at vegging, but they do a great job at keeping a plant short. Even Sativa's that want to grow tall, will stay moderately short under CFLs.

    I've never suggested to anyone to use a MH light for vegging, simply because it just seemed like a waste. The CFLs run cheaper, cooler, and because of that stop the stretching.

    You gotta figure it like this. For vegging you need about 5,000 lumens at your canopy. To achieve 5000 lumens, you don't really need a lot of light. Keep 5,000 lumens over the top of your plant in veg, and notice daily booms of growth.

    Once I am done vegging, if I don't have any other plants vegging, I'll even use CFLs for the first week of flower. Once they start to stop the 12/12 stretch, and start to put on lady parts, it's time to stick them under the 400 watt HPS and let the girls put on their sexy lady parts ;).
     
  15. So why do HID lights work for growing. If you look at the first picture, you'll see the spectral distribution for a HPS bulb I picked off google images somewhere... It's a curve, and it's trying to show you what ammounts of what colors are being given off by the lamp... You'll see that most of the lights' output is concentrated toward the MIDDLE of the spectral range, in the 500-600 nanometers region... This is mostly GREEN light. We know just from common sense that plants do not need green light at all. We can tell that because when we look at a plant and it appears green to our human eyes, what we are actually seeing is the green light reflected back to our eyes from the plant because the plant isn't absorbing the green light that is hitting it.


    The reason HPS lights make so much green light is because HPS lights primary function was to help people see in darkness, not to help people grow plants indoors... Most of the human eyes sensitivity to light lies withinthis same range of mostly green light.

    If we look to the far blue and far red sides of the chart we are most interested in, the plant more or less wants to be getting:

    Red wavelength: around 660 nm
    Blue wavelength: around 455 nm


    As you can see with the HPS example I've provided. When we compare the graph of "what the plant wants" to the graph of what the HPS provides side by side; there is very little output from the lamp that is useable to the plant. The solution? If the lamp puts out very little light useable to plants, then it makes sense to buy the biggest lamp you can right? And that's what people do... Hence the use of a 1,000 watt light that could otherwise light a small parking lot to grow just a few plants.
    The plant gets the frequencies it needs, and there is a LOT of wasted light and heat. Many HID growers don't mind this. That's fine. LOTS of cannabis is grown that way, and nothing I say is going to change that...

    The "secret?" Plants don't need LOTS of light.... They simply need ENOUGH light that's in the correct specific frequencies. Enter The LED...
     

    Attached Files:

  16. Before I go into the theory behind LED growing as an indoor technique, I just want to acknowledge that it's a science that admittedly isn't quite all the way there yet... Please don't flame or complain because I'm admitting right now it's an inexact and developing science. What I am about to present here is not at all being represented as absolute fact. This is simply my best repetition of what I have read and what I have been led to believe...

    Alright... So the concept is pretty simple. LED's could be a better choice for plant lighting for a couple of reasons. Firsst off, they emit light that is pretty narrow in frequency range... That is to say, you could buy a red LED and chances are it would have it's frequencies listed somewhere on the package in nanometers, in a similar way to how a light bulk lists a kelvin temperature...

    Let's say you buy a 630 Nanometer Red LED... I've included a slightly touched up example I borrowed from TheLEDLight.com is everything LED. Find loose LEDs, LED Flexible Ribbon, LED Modules, LED light bars,LED controls, LED fixtures, LED light bulbs, LED strips, UV LED flashlights . You can see by the diagram that most of the light output for the LED peaks narrowly at 630NM...

    For some reason 630NM or 625NM are common LED frequencies for the red range. Early models of led grow lights used these particular frequencies with unsatisfactory results... I'm pretty sure it's because the LEDs being used at the time had been designed far before growing with LEDs was ever thought possible... That's science for ya- always making mistakes to move forward...
     

    Attached Files:

    • red.gif
      red.gif
      File size:
      4.6 KB
      Views:
      35
  17. So now here we are a few years after the LED ufo first kicked off way back, and LED ufo's are much cheaper on ebay now...

    What you'll pretty much see is that few people still offer 630nanometer Red LED based products anymore. Testing and feedback indicated that this was not the most ideal frequency to use for the red spectrum. Most LED products on the market use 660 Nanometers or a mix of red with mostly 660 nanometers.

    What I think I am seeing now in the LED market nowadays is less argument over frequencies and more argument about other factors. Should manufacturers use 1watt 3watt of 7watt LEDs? Many say 1watt is now the least efficient, and so on... Also the angle of the lenses... The top of an LED is basically a plastic epoxy cap that focuses the light to certain specs- this is why LED's don't require reflectors.

    Companies are also experimenting with dimming options, and some of the products like the supernova do wicked cool tricks- LEDS mounted on different circuit boards at different weird crooked angles and stuff. The LED market is trying all sorts of cool tricks to maximize light footprint and intensity and so on...
     
  18. #58 CFLweasel, Nov 29, 2009
    Last edited by a moderator: Nov 29, 2009
    So after much deliberation, and a couple years of waiting, I settled on the G3 90watt LED ufo from HTGsuppply.com If you go to their website they have a nifty sales pitch with graphs and stuff. Note: the graphs for the 120W model are the same as for the 90W model although not displayed that way on the website.

    This is where the whole argument about LED gets tricky. Most people originally doubted LED capabilities because a 90W led unit only puts out something like 3,300 lumens (I'll have to look it up). People would look at the lumens compared to the output of their HID lights and sneer. The important message for people to remember is that although a HID has more lumens, only about 10% of those lumens or maybe even less is usable to the plant because the light is mostly the wrong color...

    So I'm going to bring back two charts- the photosynthesis chart from earlier, and the blended wave spectral output for my UFO I borrowed from the HTG website... I'll put them side by side, my light first.

    You'll notice two things:

    1) The spectral output for the G3 ufo has a decent coverage area in assorted areas of the spectrum. It is not simply two peaks in red and blue because they have included a third LED in their mix: a wide spectrum LED, which looks white to the eye because it is providing supplemental light across the entire visible spectrum. This makes for a nice chunky plot.

    2) The spectral output has a curve that peaks and overlaps the graph of photosynthesis requirements almost exactly ;)

    So it's fair to imply that although the LED light doesn't produce HUGE quantities of light, it supposedly produces light that is almost 100% usable by plants for growth...

    Sorry to double post the image but I REALLY needed them side by side to illustrate my point.... I don't have an image editor or I'd settle for an image of the requirements curve superimposed over the spectral output plot of my lamp... I don't have the software to do that :(
     

    Attached Files:

  19. So that's pretty much it... I did as much research as I could toward making a good informed decision, and I went with HTG...

    The rest is trust. I'm trusting that the spectral requirements of the plant really are as described in the above chart (not taken from someone trying to sell me something) that someone else "said" they got out of an encyclopedia and posted elsewhere... I'm trusting that the spectral output of the LED lamp I purchased really does look like the chart they provide. After all; the equipment that produces that graph (I think it's called a radiometer) costs like $20,000 so there's no chance I'm going to "check it out for myself..."

    The truth is, no matter where you go, you are undoubtedly getting a sales pitch to one extent or another... I simply read as much as I could, and went with companies I felt had the best reputation for both performance, and truth-in-advertising, good ethical background etc, and yes I tried to be cheap too :p I guess for the rest I'll have to wait and see.

    What I basically wanted to say in a nutshell is this:


    Kelvin are/can be misleading because they point us in the right direction but don't give us as much info as you'd hope/think they do,

    lumens are fairly important, but in order to really mean something to us a spectral distribution chart is extremely useful because we need to know specifically what frequencies of light (in nanometers) the light source mostly produces,

    and LED lights are trying to address some of these concerns by providing a narrow range of ideal light through a delivery mechanism that is also very electrically and thermally efficient...

    Like I said, I know it's an inexact science and it's not quite there yet, but I'm giving it a try and I'll see how it goes :)
     
  20. So if you've been reading in the LED portion of the thread, you've probably noticed that I've been going on quite a bit about the importance of light being measured in nanometers and so on.

    I've always recommended GE brand CFL bulbs from the start and after reading about them some more, it turns out they invented the CFL bulb, so I guess I wasn't too far off... Anyway, the nice thing about General Electric is that, if you look hard enough, you can dig up charts displaying the spectral power distribution curves for their CFL bulbs.

    Up until a little while ago, I didn't think this information was available from any major manufacturer of consumer CFLs but GE does, and I'm pretty sure they're the only ones...

    The link below is where I got the charts, and I'll illustrate further with the next couple posts...

    Learn About Light: Spectral Power Distribution Curves: GE Commercial Lighting Products
     

Share This Page