Hey Everybody I created this thread because mimicking the sun's rays is a complex and vital part of indoor growing especially if you are trying to grow medicine; this post should help anyone trying to learn the basics of lighting especially the two most important factors of light: lux and wavelength. Ok so some quick background info: I am currently expanding my grow into a two part operation (400W HPS for flower which I already have, and I wanted an efficient light source for veg) after some research I entered the market for a fluorescent setup (cfl, or tube). Long story short I chose a 4', 4 bulb High Output T5 ballast. The next question I had was: what is the very best bulb for vegetative/flowering/all around growth? In my search to answer this question I had to take a couple steps back and look at light in general. Heres what I found... First lets take a look at our star, the sun. This is the composition of it's light in wavelengths; we are interested in the visible spectrum at sea level. And this is the relationship between wavelength and photosynthetic activity; we are interested in the peaks. After lux, the second most important factor of light is its wavelength. Assuming sufficient lux, photosynthesis is most active at a wavelength of 440 nm during vegetative growth and 660 nm during the flowering stage as the graph above shows. You can also see that there are is plenty of radiation given off by our sun at these wavelengths; clearly cannabis (all plants for that matter) has evolved to capitalize on the most abundant wavelengths. So when we are trying to recreate the sun we must ensure that our most abundant wavelengths are in check with what we find in nature. To do this we use different color temperature bulbs. it is the color temp that causes the wavelength to change--the cooler the temp is, the longer the wavelength and subsequently the redder the light will be. Higher temp, bluer light; think about a gas burner and a match--which one burns bluer and hotter? So because bulbs are advertised using color temp and not wavelength we must convert from one to the other. However, lets come back to wavelength after we talk a little about lumens and lux. This site has good general light info and will help you determine your lux regardless of whether you use HPS or CFL. ACF Indoor Plant Grow Lights & Information Guide No one can ignore lumen output. Lumens are fundamentally important for growing indoors; if I had the perfect wavelength, but didn't have enough lux (lumen/meter^2) I would not get any photosynthesis; it would be like growing in shade. This is something that everyone should calculate for their grow rooms because even if your space looks illuminated you may still have this problem. Lux - Wikipedia, the free encyclopedia If you dont feel like reading the wiki page at least look at the graph below and know that lux=lum/m^2 Just as we used the composition of our sunlight to find the best wavelengths we must also find the lux that our star puts out and try to mimic it. Should you read the article you can see that if you are using a system that puts out 20,000+-2000 lumens (for example a standard 400W MH or a 234W High Output T5) in an area of 3'x3' you are producing at best 24,000 lux which is only equivalent to the amount of lux generated by indirect sunlight...hmmm...how many people out there veg with only a 400W MH (I do, at least until my T5 arrives)? Not to worry though (as the area the light hits decreases lux increases) so as long as you make sure your space is small enough you can have a great lux with 400W MH. Whats also of interest is the range of the lux of direct sunlight (30,000-130,000 lux). This range is due to different geographic locations across the globe; for example, lux in the sahara desert where temp hits 55 celsius clearly will be much higher than the lux generated in the himalayan foothills. Whats neat about this is that if you are growing an inbred strain and you know where it comes from you can match it's lux perfectly to the lux of it's geographic home range. If its a high altitude strain less lux will work, ect. ect. Calculate your Lux This site has a chart that gives the lumen output of various lights; everything from HPS to CFL and T8. However it doesn't include T5 lights and I am curious to know where they are at. If anyone has a link that would be great. *This site will help you determine the lux in your room* Typical Lamp Data *Remember lux=lumen/meter^2. For example I have 1 400W MH shining on a space of about .5 meters^2. lux=21,000 lumens/.5 meters^2---->my lux=42,000.* To increase lux, increase lumens (basically by increasing wattage) and/or decrease space. OK, phew. Now once we have established that we have enough lux the next thing we must do to optimize our growth is return to the subject of wavelength. For my vegetative purposes I wanted my light at 440 nm, but I also wanted an equal amount of light at 660 nm simply because though this 660 works well for flowering, photosynthesis is highly active at that wavelength as well, this way I will provide nearly the full spectrum of visible light + it will be high in concentration of wavelengths that stimulate peak photosynthesis. After bringing this up with my grow partner, who also happens to be a physics major, he consulted a textbook and found the formula: lmaxT = 2.898x10^-3 m K ...or in other words: Peak Wavelength(m) x Temp(K) = a constant 2.898x10^-3 Which is equal to: Temp(K)=2.898x10^-3 / Peak Wavelength(m) For 440(nm): 440(nm) = 4.4x10^-7(m) Temp(K)=2.898x10^-3 / 4.4x10^-7(m)= 6586 Therefore the temp I need in order to hit 440nm (4.4x10-7m) is 6586 K no surprise there as it is very close to the 6500K bulbs available and advertised for vegging. For 660(nm): 660(nm) = 6.6x10^-7(m) Temp(K)=2.898x10^-3 / 6.6x10^-7(m) =4390K Disregard this^^^ there is an anomaly. You should still use 2700K or 3000K for flowering. So in summary there are two main factors for lighting: lux, and wavelength. Think of them in terms of quantity and quality. You need to provide your plant with both. As a rule of thumb if you can provide 40,000 lux at 440nm and 660nm you are basically as close to the sun as you can get on a semi-tight budget right now. Hope this has helped. PEACE
Luxim Plasma LIFI-STA DIY Plasma light system [ame="http://www.youtube.com/watch?v=oqYl0ksLlho"]Movie[/ame] Everything you need to build the absolutely best light you could possibly find. It basically is a mini sun.
been watching those luxim bulbs for a little while. they seem interesting. might give it a try once the price comes down a bit. has anyone tried one for vegging?
I've only recently found out about these lights and as far as I can tell anyone growing MJ with these doesn't also post on the internet. The most I've seen are coral growers, and people with aquarium plants. The Monterey Bay Aquarium used them, or uses them currently in some of their exhibits. The people that do use them in aquariums all tout them as the best lights they've ever used and how much the life in the tanks seem to appreciate the natural light. The only problem I see is that you'd need at least 2 of them for a decent sized room. I would probably use them as 400w replacements, and not 1000w replacements. From what I've learned about light all factors are important and one cannot be sacrificed for another. Having a bulb with a better spectrum may not be better than a bulb that uses a lot of power and produces a high number of lumens. The Eye Hortilux Blue MH probably has the best spectral distribution of any available HID bulbs (comparable only to their 600/400 Super Blue). The Luxim site claims 120 lumens per watt, but I just can't figure out how they come to that conclusion. It's 18,300 lumens for 266 watts, which is like 69 lumens per watt. So it sounds like misleading information already, they're using bad numbers IMO, which makes me question exactly how good they are. It takes 6 of them and 1600w to equal the number of lumens from an average 1000w HID. The 1000w Eye Hortilux Blue (80K), Super Blue (110K) and Super HPS (145K) are probably the best growing bulbs as far as wattage and spectrum combined. I'm buying a 400w Blue next Friday for my new grow.
Whats the rule about posting a link to a another MJ forum? I've been watching 2 journals on these lights. one is a side-by-side test to HPS, the other is strictly plasma. results are real good, but not mind blowing.
I just updated the thread with some new info. I am also wondering what you guys think about 4400K bulbs outperforming 2700K bulbs for flowering questions/comments/info?
k, here they are: this is the one i THOUGHT was the "plasma/hps comparison grow" but its two side by side plasma grow tents https://www.opengrow.com/index.php?showtopic=40312&st=0 now this guy... is either one of the biggest jerkoffs that has ever entered a MJ forum, or there are people out there (other competing marketers??) that are excellent at making him look like one: Solid State Plasma Light Source (PLS)= future! - The Garden's Cure just Google the username he goes by, hes making his journal ALL over the internet. and gettin seriously hated on by alot of cats..
Seriously? Does nobody have anything to say about the 4400K bulbs instead of 2700K? If you use 2700K or 3000K bulbs for flower this aplies to you.
I think the problem is that most people here are folks without much experience. Ultimately all we have to go on is the science. Growers, for decades have been using these HPS bulbs for the flowering process and they do fine. Not great, not like they would under the sun, but good enough. As I understand the basic photosynthetic concept... There is less amount red and blue light in the natural spectrum than there is of green. So, chlorophyll has evolved to be more efficient at absorbing the red and blue than it has to absorb green. Basically put, they need the same amount of energy from all points in the spectrum. Since the distribution of the spectrum is not constant chlorophyll must be better at getting red and blue wavelengths. Bottom line is that by using more red and blue you utilizing the more active parts of the chlorophyll. To supply enough of the green wavelength for photosynthesis you would need much more power, which is costly.
Ahh, thanks for your input, that is interesting I did not know that that was why there were peaks at 440 and 660, but your logic makes sense, i still have a lot to learn... I do not understand exactly what you mean in the first part about the HPS light being good enough, but times are changing; it is already legal (with doctors prescription) where I live based solely on cannabis' medicinal attributes. With cannabis being used as a medicine more and more there is a growing (no pun intended hehe) emphasis on perfecting all aspects of the plant. For indoor growers that means going back to the drawing board and changing up the game plan for a different type of market. My belief is that you dont need expensive systems to bring the sun inside. The ball of gas we call our sun is far far away so it in itself has absolutely no affect on plant growth. Of course everyone knows this, I am just trying to emphasize that it is the light and the light only that our beloved plants have adapted to. If we meticulously analyze the spectrum of light (the full spectrum not just the visible--infrared and UV to start) and the lux found outdoors we can use this knowledge, coupled with our knowledge of lighting to recreate the suns light to near perfection--at least this is what I believe right now. You do not need a plasma bulb to create perfect light (of course if you can afford one by all means go for it, it will simplify your setup; the trade off is $).
This is an interesting thread. You see this image tossed around forums alot: The problem is that converting these Kelvin numbers above to nanometers of wavelength, the peaks on the right don't jive with widely regarded published chlorophyll absorption spectra graphs like below (and like clos3tgrow3r posted). The top chart shows the "red" peak at around 2200K which is equivalent to about 1320nm (using the MUCH easier formula of WL=2900000/K). The chart below and many others from botany texts show the chlorophyll red peak at 660nm which equates to ~4400K per clos3tgrow3r's calculations. Maybe the problem comes from the fact that the top chart which everyone seems to go by was created by an online hydro shop which might be more interested in selling bulbs than publishing good science. Who knows. I think clos3tgrow3r is on to something.
Very interesting 2 posts john thank you for that. As far as the first one is concerned I too thought that it might be possible the lighting industry is selling the 2700K bulbs just because the indoor growing industry is not big enough for manufacturers to supply special bulbs especially for us--and hydro stores are just punting out the common 2700K bulbs. But its hard to imagine that the truth wouldn't have already come out if that was the case. Anyways thank you also for the photosynthesis one, it was very informative and im sure that will come in handy one day. Unfortunately for now, After some more research I haven't found anything conclusive about the 4400 and 2700 problem and although I know my calculations are right I think there might be an anomaly of some sort that makes 2700K bulbs produce red light and 4400K bulbs bright white light. I was surfing the web trying to find info on 4400K bulbs and what I discovered was that the most common source of these bulbs is in the car headlights industry, all advertised as super white... This is very confusing and means I have to go back to the drawing board on this one--the conclusion I came to is that apart from color temp there is at least one other factor that affects the wavelength. Perhaps source of electrons (sodium, mercury vapor, halogen, ect...)? Right now I feel like I am trying to prove an already existing formula but what the hell.
Hi Closetgrower... I like your thread It's interesting what your friend came up[ with in the way of a formula to convert from kelvin temperature but i'd be skeptical unless it was somehow specific to a certain vendor... I too have been doing loads of reading lately also. A great place to look is ge lighting's webpage. There's a section called "learn about light" that's fabulous... Anyway, from what I understand, Kelvin color temperature is a number tailored to human vision... The reason degrees kelvin are used is because if you heat a "black body radiator" (such as a nugget of carbon graphite) up to 6500 degrees kelvin (HOT!) it will give off a light that appears blue to your human eyes... If you only heat it up to 2700 degrees kelvin (still really HOT), it will glow a orange/red color, and so on... When a light bulb has a color rating of 6500K, what the manufacturer iss trying to say is that to your eyes, the bulb will put off the same approximate color blue as a black body radiator heated to 6500 dgrees kelvin... The color given off by any kind of fluorescent tube is the product of it's "phosphor coating..." This is a powdery chemical mix of stuff... What happens is that the mercury (or amalgam) vapor arc inside the fluorescent tube gives off some sort of energy other than light energy (some sort of radiation I guess, I'm no exper either), but it is the phosphor that absorbs that energy and re-converts it to the light energy that is given off by the bulb... The problem is that fluorescent bulbs are sort of like paint... You can get eggshell white from 3 different manufacturers, and they will all look the same to your eyes even though they are each completely different. The same is true of phosphor coatings... Since the light we see given off is a mix, it is possible for multiple manufactureres to produce multiple bulbs that produce the "same" color light with different formulas. I'm willing to admit that there probably is a formula you can use to suggest where most of the spectral output of a bulb lie, I doubt it is scientifically possible to determine a bulbs spectral composition from it's kelvin temperature alone... If you look to the link in my signature, you can scoll around and see I make the same argument- GE 6500K "daylight cfl bulbs have more usefull light in blue and red than the 2700K bulbs. I even go so far as to suggest cfl growers use only the 6500k bulbs offered by GE for exactly this reason... If you look here: Learn About Light: Spectral Power Distribution Curves: GE Commercial Lighting Products GE lists the spectral outputs for all of their major lines of bulbs... Technically the "cool white deluxe" phosphor puts out the best spectral mix... In fact, I believe Todd McCormick mentioned something along these lines in his "how to grow medical marijuana" book from 1999... He said something abou how he had tried the "special bulbs" and the light looked nicer but grew worse... I suspec that the reason these bulbs are no longer in use is that, although the spectral output is more ideal, the lumens/watt ratio is notably less efficient... Also, the bulbs containing these phosphors are typically 4 feet long, and in some rarer cases 3 feet, so tighter spaces become more difficult... CHEERS!
A sligt correction to my earlier post: The cool chite deluxe phosphor from GE is available on many types of bulbs... but mostly appliance bulbs- small, inefficient etc... The largest bulbs they make which use it ate t12 bi-pin, which from my understanding were considered to have been superceeded by t5ho, even though the spectrum is less ideal... The reason? I'd like to pitch yet another photosynthetic response curve graph here: http://forum.grasscity.com/attachme...heres-why-correct-spectral-response-curve.gif The photosynthetic response curve most people show with only one line is the averaged wave from the components shown in the graph above, most imnportantly cloryphyll A and B... If you look, cloryphyll A responds to the low 400nm range and the deep-red (6760nm) range, while cloryphyll B responds more around the 470nm blue range and the early red (630nm) range... From what I can tell, early grow lights, both fluorescent and LED alike were sim[ply reworked technologies from earlier lighting designs. Lighting designs which were not originally conceived with plant growth in mind... AS a result the spectrums they produced were useable but less than ideal... For example, the first generation led ufo from prosource contained blues in the 470nm range and reds in the 630nm range... Why? both colors were already available from other commercial applications... Unfortunately the result was a spectrum which stimulated cloryphyll-B production (peaks at 470nm and 630nm) but produced little useable light to stimulate cloryphyll-a production... The results? inferior growth... The same seems to be true of cfl and other fluorescent lighting. From what I see, many of these bulbs still produce most of their red light in the 630nm spectrum, which means in order to properly accomodate the production of cloryphyll-a production, more output around the 450nm blue range would be needed, which sadly most of these bulbs also seem to lack... I don't think it would be hard to engineer a new fluorescent phosphor which peaked at 450nm and 660nm but I suspect they don't want to spend the money to develop such a product because they don't realize the profit potential... Think of it this way: the only reasn LED is gaining a foothold in the industry as of right now is because people like me believe that the led's are the best source of light because their outputs can be tailored to very specific frequencies, therefore relative luminous output is less (not completely) significant. Imagine if a pluorescennt phosphor could be developed to produce a similarly tailored light output? Well, then we'd get the best of both worlds- matched frequencies with maximum lumens/watt- a near ideal plant-ready-PAR light source! There may be a reason this hasn't been done... Maybe the chemmicals required to produce a phosphor of those specifications would be toxic or hazardous... Maybe it would be impossible because the bulb would end up putting out additional dangerous ultravioled frequencies due to chemical impossibilities... Then again, if you look here: Learn About Light: Spectral Power Distribution Curves: GE Commercial Lighting Products and click on the plant and aquatium phposphor, you'll see the output is even better! (read the y axis and you'll see the scale is magnitudes larger)... Yet nobody seems to use these bulbs. Why? perhaps they are only or mostly offered in incandescent, and therefore their optimized spectral output is basically worthless because there's little lumens/watt like you mentioned yourself earlier... It's all about balancing those two factors... Not to sound crazy but maybe the government/corporate world allows the cannabis growing community to think that 2700K bulbs are better for flowering. Maybe it saves big companies big money on re tooling. Maybe corporate amarica feels it is their moral obligation to mislead us and allow us to grow under less-than-ideal lighting conditions because it better suits their own moral standards to do the right thing, and to most companies, cannabis cultivation is a reprehensible and a-moral high crime... Another interesting point of note- KNOW YOUR MANUFACTURER... Like I said, since kelvin temperature is relative to human vision, spectral outputs will chage from manufacturer to manufacturer... Don't believe me? Go here: http://ecom.mysylvania.com/miniapps/FileNet2/PIBs/CF026.pdf and read about sylvania's "dulux el" line of household cfl bulbs... While the useable output in the blue range is debatable, none of their bulbs produce any light worth mentioning after 600nanometers! That means, no matter which temperature bulb you select, if you buy it from sylvania; it will suck for flowering.... I haven't quite gotten the answer yet, but there's definitely something lighting companies aren't telling us... Check my thred from time to time- I'm working on an .xls spreadsheet to make comparisons way easier. I'll share when done... CHEERS!
Sorry to keep posting in here, not trying to hijack the thread but I wanted to rant some more about color temperature... Like I said before, Kelvin color temperature is a measurement relavent to human eyesight. Just because two bulbs have the same color temperature doess not mean they have the same spectral output at all. Remember the example with the sylvania cfl bulbs? They managed to make a 2700K "red" bulb with almost no red light component. Kelvin temperature is useful for selecting light for your home. It is almost useless without the spectral output chart... Unfortunately, most light bulbs are sold without this information because, inversely, it is almost useless information for someone selecting lighting to use in the home.
Overall I thank you for your input although it was a little lengthy and confusing. I get the feeling like you didn't really read my thread but just my responses...idk... My responses to some parts of your post are in bold.
This is what confuses me. It just doesn't make sense. How can you make a 2700K bulb have peak wavelengths at 660nm. For example even if the lighting industry is just using, say the light produced by a blackbody radiator at 2700K as a standard for the color of light the bulb they produce will put out. Wouldn't they still have put out the same wavelength because isn't color determined solely by wavelength and thus wouldn't color temp and wavelength be rigidly tied together are there other ways to change lights color? If they are trying to advertise a bulb with its peak light in the red spectrum they would need use a wavelength between 620–750 nm which means (I used the conversion formula for this) a color temp of between 4674-3864 K, neither of which are recommended for flowering. The only explanation I can think of is that the 2700K and 3000K bulbs still produce a decent amount of red light just that it is not the most abundant wavelength...I am going to try to find a formula for spectral distribution to get to the bottom of this.kjkdbfkebfk
Whoa whoa whoa! What's with all the hostility man? I'm not trying to start a pissing contest but what I will say is this: I am sorry my reponnse was really confusing and all over the place. I was high... Yes yes, I understand the formula is a real formula from real scientists etc. When I said "the formula your friend came up with" I obviously meant the one he came up with from a reference book or something- DUH! I'm just giving him credit for bringing it forward to you... Although the formula may be "indisputable", the data it gives us is only part of the answer... As I demonstrated in the photosynthesis response curve earlier, plants do respond to a diverse group of supplemental frequencies. While I'll definitely agree that it's absolutely great to know the peak frequencies as a starting point. There may be some bulbs with different peaks but wider ranges that could actually perform better. For making an objective decision- nothing beats an actual spectral output curve. If selecting a grow bulb was as easy as applying a formula to a color temperature, people would have posted that in sticky's everywhere ages ago. nothing beats an actual spectral output curve. "Why does a 4400K bulb produce super white light then? 4400K should produce light in the red spectrum at 660nm." dude seriously? why on earth do you think I am disputing why a 4400K rated bulb is mostly white? When you heat a "black body radiator" material to 4400 degrees Kelvin, it glows the same ralative color white as the 4400K bulb. That's why the bulb has a color temperature of 4400k. What's so hard to understand about that? Here's a chart: http://forum.grasscity.com/attachme...hps-dont-bother-heres-why-kelvintempchart.jpg See? That data I'm already representing agrees with what you are saying... The 4400K bulb may very well contain a fair ammount of 660nm light, but for whatever reason, it doesn't look that way to our eyes. If you google "human eye color response" eventually you'll find a chart with the curve of human eye response to different frequencies... At 660nm the human eye response is very low. Human eyes respond best to light at the center of the spectrum in the 500-600 nm range... I'm sure that's a part of it... I'm trying to agree with you here bro... All I'm saying is this- if you're going to start a thread and address the relation between light measured in nanometers and kelvin color temperature; don't do so if you don't first understannd the fundamentaals of how the kelvin color temperature system works in the first place. While you and your physicist friend have a nifty liuttle formula for extracting a peak wavelength from an otherwise (almost) useless piece of information, you never once in your thread attempt to either 1) explain how the kelvin color temperature works or 2) admit that the best you can do with a kelvin color temperature rating is extract a peak value because kelvin temperaature ratings were not intended to express light in nanometers. If they were your scientist buddy would have a formula to extract the whole thing. I think it's great for providing clues but I also think you're largely discounting me without cause or provocation... sorry about all the typos- I'm on a netbook and just don't carre -Weasel