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Cool tube vs. bare bulb test, just for kicks
- Thread starter flat9
- Start date
Okay so I think I've got this figured out. Firstly, PPFD, stated in units of micromoles per square meter per second, can be converted to lux (roughly, since it is wavelength dependent) according to the conversion factor of 82 for HPS lamps, found here:
http://www.apogeeinstruments.com/conversion-ppf-to-lux/
1500 micromoles/(m^2 x s) x 82 = 123,000 lux = 123,000 lumens/m^2
To convert this to watts per sq meter, you must divide by luminous efficiency, which for HPS lamps is 117 lumens/watt. See details here:
http://www.rapidtables.com/calc/light/lumen-to-watt-calculator.htm
That gives you 1051.2820513 watts/m^2. Last step is to convert to watts/ft^2, which is done by dividing by 10.764, the number of square feet in one square meter. This gives you roughly 98 watts per square foot.
Upshot: According to the source, there is little/no growth beyond 98 watts per square foot.
This doesn't tell us how growth slows up to that point, only that there's no point going beyond 100 watts per square foot....
http://www.apogeeinstruments.com/conversion-ppf-to-lux/
1500 micromoles/(m^2 x s) x 82 = 123,000 lux = 123,000 lumens/m^2
To convert this to watts per sq meter, you must divide by luminous efficiency, which for HPS lamps is 117 lumens/watt. See details here:
http://www.rapidtables.com/calc/light/lumen-to-watt-calculator.htm
That gives you 1051.2820513 watts/m^2. Last step is to convert to watts/ft^2, which is done by dividing by 10.764, the number of square feet in one square meter. This gives you roughly 98 watts per square foot.
Upshot: According to the source, there is little/no growth beyond 98 watts per square foot.
This doesn't tell us how growth slows up to that point, only that there's no point going beyond 100 watts per square foot....
Get a light meter, they're really cheap and important. (just to test used bulb output alone is worth it) Vert or horizontal, at 100w/sq ft most of your foliage is going to be nowhere near 120k lux. A year ago I spent time looking for the same data sources you found and ended up with the conclusion that there is a lot of wiggle room beyond 50w/sq ft. (It started when I noticed one cola a year ago in my tree room that was atypically close to a light, getting about 80k lux instead of 40k lux and the buds were twice as big. )
And keep in mind that in an indoor grow room light doesnt necessary hit the leaf at a direct angle. If you have 50k lux hitting a cola from one side and 50k lux hitting the same cola from another side, that's a lot more efficient than it being directly hit 100k lux from the top. With a light meter you could get a misleading reading because you're aiming the sensor at one angle and the light is hitting from a different angle.
And also I have no clue if it's true but a umol meter might not be as accurate as a lux meter, because of the way they convert the lux reading to umol depending or not depending on the light spectrum. Though someone else please chime in if you know because the opposite may be true.
And keep in mind that in an indoor grow room light doesnt necessary hit the leaf at a direct angle. If you have 50k lux hitting a cola from one side and 50k lux hitting the same cola from another side, that's a lot more efficient than it being directly hit 100k lux from the top. With a light meter you could get a misleading reading because you're aiming the sensor at one angle and the light is hitting from a different angle.
And also I have no clue if it's true but a umol meter might not be as accurate as a lux meter, because of the way they convert the lux reading to umol depending or not depending on the light spectrum. Though someone else please chime in if you know because the opposite may be true.
D
DHF
Farm , You know I appreciate your input and that you add solid reference from book sources and studies , but for you to state that a cola from 1 of your plants in an isolated incident that was closer to the light source with 100 watts per sq ft and "double" the size of the other nugs on the same plant or even plants next to it , is as flawed and biased a statement as I`ve ever read on a weedsite that MANY new members read and rely on , so please....
Let`s keep advanced and intermediate experimental attempts at growin dope to a minimum cuz MOST folks don`t ever get close to 50 watts per sq ft until they pass the "hobby grower" status.....IOW....
Why on God`s green earth didn`t you expose ALL your plants the VERY next following run to the EXACT same light so THEY would all be "double the size" of all your previous plant setups....I`m just sayin.....
Let`s keep it real and "tested" , not speculative....and I applaud and respect ALL ya`ll efforts to do better , grow bigger and better , and dial your own lil world`s setup , but again.....1 more time....
No matter what you read in university studies , and what other scientists have claimed to have produced , they don`t grow the shit for production OR to smoke the shit , so ALL should be taken with a grain of salt and repeated to see IF anything of the sort is possible in YOUR setup/environment/geographical location on earth....
No offense intended in any way , shape , form , or fashion , but from what I`ve witnessed first hand over waaaay too many yrs ta think about , the shit just don`t work like that without guaranteed heat/light/environmental stress to overcome , and ....
STILL yields will NOT increase , only density and quality of nuggage , and that`s from many many many experienced growers from back in the day that read ALL or close to the same studies ya`ll been seein....anyways....
2 exact same plants side by side exposed to the same 100 watts per sq ft with 1 "atypically" closer to the light source WITHOUT bleaching or scorching out and frying , and the other as said above further away ending up HALF the size of the closer plant just will not happen....just don`t work that way Farm.....
This is my last post in this thread , cuz ya`ll are after something that`s not there , but as stated earlier far be it from me to squash the quest for knowledge and practical application OF said knowledge , but guys.....I`m from Missouri and yas gotta "show me"......talk`s cheap...
Peace....DHF.....
......
Let`s keep advanced and intermediate experimental attempts at growin dope to a minimum cuz MOST folks don`t ever get close to 50 watts per sq ft until they pass the "hobby grower" status.....IOW....
Why on God`s green earth didn`t you expose ALL your plants the VERY next following run to the EXACT same light so THEY would all be "double the size" of all your previous plant setups....I`m just sayin.....
Let`s keep it real and "tested" , not speculative....and I applaud and respect ALL ya`ll efforts to do better , grow bigger and better , and dial your own lil world`s setup , but again.....1 more time....
No matter what you read in university studies , and what other scientists have claimed to have produced , they don`t grow the shit for production OR to smoke the shit , so ALL should be taken with a grain of salt and repeated to see IF anything of the sort is possible in YOUR setup/environment/geographical location on earth....
No offense intended in any way , shape , form , or fashion , but from what I`ve witnessed first hand over waaaay too many yrs ta think about , the shit just don`t work like that without guaranteed heat/light/environmental stress to overcome , and ....
STILL yields will NOT increase , only density and quality of nuggage , and that`s from many many many experienced growers from back in the day that read ALL or close to the same studies ya`ll been seein....anyways....
2 exact same plants side by side exposed to the same 100 watts per sq ft with 1 "atypically" closer to the light source WITHOUT bleaching or scorching out and frying , and the other as said above further away ending up HALF the size of the closer plant just will not happen....just don`t work that way Farm.....
This is my last post in this thread , cuz ya`ll are after something that`s not there , but as stated earlier far be it from me to squash the quest for knowledge and practical application OF said knowledge , but guys.....I`m from Missouri and yas gotta "show me"......talk`s cheap...
Peace....DHF.....
......
Only density and quality will increase. Please expand on this dhf.
If by quality you mean a higher bud to leaf ratio, then the trimmed yield would be increased. Are we talking increased potency? You get a better price.
I'm only using 45wpsqft and I got a 25% lab score. I'm happy with that. I might bump it up to 50-55wpsqft.
If by quality you mean a higher bud to leaf ratio, then the trimmed yield would be increased. Are we talking increased potency? You get a better price.
I'm only using 45wpsqft and I got a 25% lab score. I'm happy with that. I might bump it up to 50-55wpsqft.
D
DHF
BH......This is about increasing yields with 100 watts per sq ft according to the above posts , or did you miss that cuz you`re in attack mode.....
When I upped my watts per sq ft to 50 , my plants looked completely different from the PRONOUNCED trichome production increase , bud density , and overall "quality" compared to the EXACT same plant I ran almost a decade @ 34 watts per sq ft......
Go back and read instead of scanning over shit.....but...I said my last post was the last , so I`ll stay outta this 1 as stated earlier and maybe since you know NOTHING of 100 watts per sq ft , maybe YOU can chime in with some of YOUR experience ...oh...I forgot....
You have none in this respect , now do you.....
Sheesh....
When I upped my watts per sq ft to 50 , my plants looked completely different from the PRONOUNCED trichome production increase , bud density , and overall "quality" compared to the EXACT same plant I ran almost a decade @ 34 watts per sq ft......
Go back and read instead of scanning over shit.....but...I said my last post was the last , so I`ll stay outta this 1 as stated earlier and maybe since you know NOTHING of 100 watts per sq ft , maybe YOU can chime in with some of YOUR experience ...oh...I forgot....
You have none in this respect , now do you.....
Sheesh....
I have no idea what you're talking about. You might have misunderstood what I said. I was simply giving an anecdote as to why I became interested in exploring higher light levels back when I was growing 30-70w /sq ft. (tried a number of setups) I'm not implying that such a tiny example is proof of anything. What is relevant is that there are many real world growers who use high light intensity for very high yields per sq ft and get a decent to excellent gpw.
Here are some others examples to add:
https://www.icmag.com/ic/showpost.php?p=1566357&postcount=63
Valuable info in other posts by Texas Kid in that thread as well...
If you can't increase yield beyond 50w/sqft, this would mean overgrow00 would have been getting 1.6gpw if using a 400 instead of a 1000 for their grows:
https://www.icmag.com/ic/showthread.php?t=45767
Other sites have many more examples. (not allowed to link) And again after a year of 30-70w/sqft I halved the space using the same watts and got similar yields for a year, double the yield per square foot. I did this with medicore skill and effort (at best) so I'm sure others could do a lot better. I didn't mean to post so much in this thread, I just wanted to express the opinion to everyone that high watts per square foot is worth considering. If you try then please post about it so we can all learn more
DHF -- just so we are clear, in posting this information that I found I am by no way trying to show you up or anything of that sort. Trust me, almost everything I've read that you've written on these forums has been absolutely INVALUABLE, and I am very thankful for that. It's more about just trying to understand as much as I can, you know what I mean? If I could teleport you to my grow op and have you run it for me, no doubt you'd best me by miles! But I can't, so I gotta learn as much as possible. Learning as much as possible for me doesn't mean I want to take everything you say as truth if I have seen reports to the contrary, though no doubt you know WAY more than I ever will about growing. It's all about learning, right? Anyway, I just hope you know I'm not trying to show anyone up, and I really appreciate your input and that you help guys like us out. It's honestly an awesome thing you do man.
Speaking of which, I think you made a really great point about the presence and/or absence of glass, which is what started this thread for me in the first place. I don't have access to that paper yet, but it could be that they were using hoods and maybe 98 watts/sq-ft equates to something more like 75 watts/sq-ft for bare bulbs. Furthermore, what we still don't know is precisely HOW the growth slows to a stop at their result of 98 watts/sq-ft. In other words, the break-even point in terms of profitability may have been reached much before that point (maybe at 55 or 60 in terms of bare bulbs?) and there are just very tiny incremental gains up to their reported max which aren't worth it in terms of $.
Farmari -- actually PPFD is the more accurate reading in terms of what plants care about, and those conversion factors are based on the typical light spectrum for an HPS bulb. Your particular bulb will make a difference, though most HPS bulbs exhibit extremely similar spectrums (or at least they're advertised a such). Anyway, PPFD is basically the integral (area under the curve) of the light emitted from a source at all spectrums in the photosynthetically-relevant region. Lux, however, refers to the portion of light to which our eyes respond (not so relevant for plants).
And as for whether you can get a meter, well you can, but so-called PAR meters (which measure PPFD) are about three hundo which is too rich for my blood. I did, however, see a cool little kit somewhere for a spectrometer that you can hook up to a laptop which was about 100 bucks. That may be worth the investment...
Speaking of which, I think you made a really great point about the presence and/or absence of glass, which is what started this thread for me in the first place. I don't have access to that paper yet, but it could be that they were using hoods and maybe 98 watts/sq-ft equates to something more like 75 watts/sq-ft for bare bulbs. Furthermore, what we still don't know is precisely HOW the growth slows to a stop at their result of 98 watts/sq-ft. In other words, the break-even point in terms of profitability may have been reached much before that point (maybe at 55 or 60 in terms of bare bulbs?) and there are just very tiny incremental gains up to their reported max which aren't worth it in terms of $.
Farmari -- actually PPFD is the more accurate reading in terms of what plants care about, and those conversion factors are based on the typical light spectrum for an HPS bulb. Your particular bulb will make a difference, though most HPS bulbs exhibit extremely similar spectrums (or at least they're advertised a such). Anyway, PPFD is basically the integral (area under the curve) of the light emitted from a source at all spectrums in the photosynthetically-relevant region. Lux, however, refers to the portion of light to which our eyes respond (not so relevant for plants).
And as for whether you can get a meter, well you can, but so-called PAR meters (which measure PPFD) are about three hundo which is too rich for my blood. I did, however, see a cool little kit somewhere for a spectrometer that you can hook up to a laptop which was about 100 bucks. That may be worth the investment...
Yes HPS tends to have very similar spectrum ( Ulbricht sphere PAR test (PPF) of several popular 1000W lamps ) so for comparative purposes it's nice and simple when growers post measurements with lux/fc.
Does all equipment measure PPFD in the same exact way, to where two different brands will give the same output ratio between a HPS and CFL for example? That's what I'm wondering... if I recall right, I've seen significantly varying graphs online by equipment manufacturers of how they interpret PPFD through the visible light spectrum. If that is the case then maybe one PPFD meter when reading 50k lux of HPS will say 500umol while another meter might say 700umol, you know?
But then, maybe cheap luxometers tend to be much less accurate. If anybody knows please chime in here! But you can get a luxometer for 20usd or so on Amazon or other places.
Does all equipment measure PPFD in the same exact way, to where two different brands will give the same output ratio between a HPS and CFL for example? That's what I'm wondering... if I recall right, I've seen significantly varying graphs online by equipment manufacturers of how they interpret PPFD through the visible light spectrum. If that is the case then maybe one PPFD meter when reading 50k lux of HPS will say 500umol while another meter might say 700umol, you know?
But then, maybe cheap luxometers tend to be much less accurate. If anybody knows please chime in here! But you can get a luxometer for 20usd or so on Amazon or other places.
PPFD literally means photosynthetic photon flux density. So it's the total number of photons emitted in the photosynthetically active wavelengths per unit time per some unit area of the sphere. Had it just been photon flux density, same thing but all wavelengths, not just from 400 to 700 nm.
If you want to get all mathematical about it, actually necessarily any two meters will measure different things because the detection of photons is a Poisson process (Wiki it!). This means there necessarily is some variance in the measurements using the same meter, or any two different brands of meters, though this variance is probably quite small (95% of measurements probably lie within +/- 2% or something). The more expensive brands will probably have more sensitive meters that will reduce this variance. But in general, I'd expect these sensors to be unbiased -- they tend to neither overestimate or underestimate the light. You probably will get much better readings by taking an average of like 10 measurements rather than just one.
The same is true of lux meters (which also are detecting photons but just in wavelengths relevant to human's eyes rather than to plants). Necessarily will have variance in the measurements.
Anyway, if we are to believe that paper I quoted the abstract of, you're overdoing it with 110 watts/sq-ft. :-D And why no bare bulbs?
If you want to get all mathematical about it, actually necessarily any two meters will measure different things because the detection of photons is a Poisson process (Wiki it!). This means there necessarily is some variance in the measurements using the same meter, or any two different brands of meters, though this variance is probably quite small (95% of measurements probably lie within +/- 2% or something). The more expensive brands will probably have more sensitive meters that will reduce this variance. But in general, I'd expect these sensors to be unbiased -- they tend to neither overestimate or underestimate the light. You probably will get much better readings by taking an average of like 10 measurements rather than just one.
The same is true of lux meters (which also are detecting photons but just in wavelengths relevant to human's eyes rather than to plants). Necessarily will have variance in the measurements.
Anyway, if we are to believe that paper I quoted the abstract of, you're overdoing it with 110 watts/sq-ft. :-D And why no bare bulbs?
It wasn't an attack, I want to know what the difference is in quality between 50 and 100wpsqft. I've seen the difference between 35 and 50wpsqft. The increase in quality could be beneficial enough to justify the extra light, or not. Personally I'm satisfied with my lab scores, but there's always room for improvement.
speaking about experience... it doesn't sound like you've ever gone over 50wpsqft yourself. So you are speaking in theory? Secondhand experience?
my post doesn't require response if you're on the attack. I can always do the work myself to find out the answer.
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D
DHF
As stated earlier since once again you "scan" over the thread , but "hone in" on my posts poised to jump in and start an argument , your assumption that I`ve only run at 50 watts per is again , an assumption....and....
What I`ve seen online over the yrs , compared to the numerous times I`ve been to medville and helped with settin up and tweakin many old head bro`s areas "including" the rooms they set up to test watts per sq ft back in the day , cuz ......
They ALL did to find the optimum light without compromising environment "happy medium" , and my "second hand opinion" per your snide remarks has been JUST as hands on as it has from observation with documentation online......that said...
You slingin around statements such as producing so called "25%" THC products with 45 watts per sq ft , which is MOSTLY genetics and NOT grower expertise although some knowledge helps , just proves MY point even further that by jumpin into the realm of 100 watts per sq ft , the only thing increased "for the most part" is your power bill , with diminished returns RIGHT behind it without TOTAL environmental control....and then....
As I also said earlier since you most likely didn`t read it either , was that your "poke" at me saying overall quality as in " bud density and trichome formation WILL improve , and why ?.....
Because WHEN the plants are exposed to even MORE abnormal light penetration/intensity , their DEFENSE mechanism AND survival mode FORCES em to produce more resin during "lights on" , and tighten up calyxes/bud denseness to preserve seed production/viability during "lights off" like they do outside for mother nature "in the wild" is GUARANTEED.....if they don`t fry from too much bein too much.....so lastly....
The only thing left for me ta say to you BH is if you HAVE no experience with 100 watts per sq ft as duly noted by yourself , how about BEFORE you come in a thread about it , have something constructive with a leg to stand on before spouting "possibilities" instead of saying with a comeback that.....
"You can find out for yourself" as Farmari`s been attempting to do so , instead of just "throwin 2 cents worth" in to ATTEMPT to sling shit my way , how bout reading further that my last post was about staying out of the thread for Farm and Flat to further discuss and ponder all the possibilities of increased wattage....now....
Is there ANYTHING else you wanna sling this way ?....if so do it in PM cuz I`m outie on this thread AND subject....
Peace...DHF....
....Hey bobblehead I've read conflicting opinions and I personally cannot say one way or the other. No comparative lab tests, and by ingesting I cannot tell the difference, from the same strain grown 35w/sqft, 70w/sqft, and 130w/sq ft.
Density will increase significantly, which some medical patients love, (I don't know why, honestly) but in terms of potency or taste I personally cannot say there has been a significant difference, and only have read others say density increase but not really potency. I could be wrong!
