Investing in new lights LED or HID?

[asde²]

Once again, that is measured at the SOURCE (the lamp), PPF = umol/s, NOT umol/m^2/s, i.e., PPFD at the canopy. So once again: there is NO way to accuratly convert from PPF to PPFD! And besides, you didn't mention the level of PPF, how did you find the PPF? (don't tell me you used KNNA's spreadsheet beucase I already debunked that).

Who cares that it might equal the 600w plantastar? (the datum I assume you got from KNNA's spreadsheet) As I have shown time, after time, after time, after time: we want at least over 1,000 PPFD!

if the led puts out the same ppf, the amount of photons reaching the canopy is higher for led light means the ppfd is higher - higher ppf means higher ppfd if the spread is the same and led is winning this because there is no loss (which is impossible for hids) before canopy is reached


to correct myself: i ment the greenpower 600w not the plantastar, ppf value for it is 1.92/W - the led reach 1.91/W
if you dont believe my numbers -> the datasheets are available all over the web and free for all, do it on your own is the best i think.. maybe it can help you to face the reality again

are you in support of LEDs or HID?

Thanks.

made my day.

 

[secondtry]

No it does not! PPFD is greatly affected by distance to canopy, and it matters not if it's red or blue or green. THERE IS NO WAY TO ACCRUELTY CONVERT FROM PPF TO PPFD!

and PPF IS NOT by watts, it's umol/s!

God damit, the next idiot who posts what ever comes out their ass is going to give me an aneurism!

 

[MerryPrankstr]

Fact:
At one time in the world. it was a well established fact that the world was flat.
Fact:
At one time in the world. it was a well established fact that heavier than air machines can't fly.

In fact, all scientific facts are actually temporary statements until better and more complete understand of underlying principles involved are known.

The facts you refer to are always open to further examination and understanding. To treat them any other way is to turn them into dogma, hence my precise use of the word.

In fact, although I am certain that they are capable of exceeding HID's capabilities. If you doubt my word take a look at the work Weezard did at Cannabis.com did in his experiment of high powered LED's vs Tropical Sunlight.

No amount of math or "logic spin" can negate documented experimentation of this type.
I suggest that your time might be better spent recreating his experiment to verify or refute his work, rather than argue with everyone who doesn't agree with you.

And for the record, I worked for over 40 years at a top level Medical Research University and understand the usefulness of research. I lived through the Newtonian, Einstein and and Quantum explanations for the laws of physics.

Biology is no different. What we think we know now is not the end of the journey.

And it takes an open mind to actually recognize new principles, hence the need to have an open mind when one works in the scientific field.

BTW for the record, although high output LED's work right right now I usually suggest to anyone who asks that unless there is a compelling reason to use them now, it is financially prohibitive.

That will change as manufacture ramps up and production prices drop. A fact of the laws of economics.

 

[supermanlives]

wow this thread has got technical. lets just say led can grow dope. i am still waiting for a watt per watt thread where about the same wattages are actually compared. i aint mortaging my house to setup an led grow just yet. if i wanted lower yields with less penetration i would use floros.

 

[MerryPrankstr]

Supermanlives, 15 watt + per emitter are needed. Right now a 85 watt device of this type cost around $600.00 in parts. Labor, etc. not included. HID is still king in the practical world for a while yet. Guestimations are that around 2114 enough will have been made to make them as cheap per watt as HID's. Who knows in this economy, though (LOL) !

 

[secondtry]

Fact:
At one time in the world. it was a well established fact that the world was flat.
Fact:
At one time in the world. it was a well established fact that heavier than air machines can't fly.

In fact, all scientific facts are actually temporary statements until better and more complete understand of underlying principles involved are known.

There is NO SUCH THING AS FACT in the world of scientific experiments, there is only "proven scientific thoery", the very reason is like you cite, new science can come along and disprove old science, but that ain't gonna happen with LEDs unless they start offering green photons and very high irradiance...wait...that would make them the same as an HID!!! So just use an HID and save yourself decades of waiting for know-nothing LED makers to make a LED arrays which matches the Quantum Yield curve of higher plants like HID already match!!!

In fact, although I am certain that they are capable of exceeding HID's capabilities.

Care to prove that with analytical scientific data like I have proven the opposite near over a thousand times?

If you doubt my word take a look at the work Weezard did at Cannabis.com did in his experiment of high powered LED's vs Tropical Sunlight.

Yea, and that is a totally dumb comparison on part of Weezard!

There are things which happen to plants outside called "midday depression", "multi-peak photosynthesis", "photoinhibition", "photorespiration", high "vapor pressure deficient", etc, etc, which can account for the results. There is no way one can compare a grow inside to a grow outside, especially in the tropics where it gets hot and the sun emits high irradiance! That experiment is silly and obliviously Weezard has no grasp of 'photo-botany'...

No amount of math or "logic spin" can negate documented experimentation of this type.

I agree no "logic spin" can negate that, only the FACTS about how plants grow outside can. Geeze! I think it should be mandatory for all cannabis growers to take botany classes!

I suggest that your time might be better spent recreating his experiment to verify or refute his work, rather than argue with everyone who doesn't agree with you.

Hehe, yea right, see my previous comments about that idiotocray [sic]; like I have written a thousand times, the best way to compare lamps is by PPFD because we KNOW what PPFD offers most rate of photosynthesis in cannabis and highest net rate of photosynthesis; and we also KNOW that the higher the rate of photosynthesis the potentially higher the yield.

And for the record, I worked for over 40 years at a top level Medical Research University and understand the usefulness of research. I lived through the Newtonian, Einstein and and Quantum explanations for the laws of physics.

Maybe you need to brush up, hmmm? Or just read what I have posted, I have definitely posted a whole semester (or two) worth of info here, and so few people appreciate it, nor jump at the chance to learn REAL info about plants, photosynthesis, light quatnum physics and photosystems I and II of said plants.

And it takes an open mind to actually recognize new principles, hence the need to have an open mind when one works in the scientific field.

I have a very open mind, I just know the science behind it, so I can make a judgment, you on the other hand obviously do not, and thus can not...

 

[MerryPrankstr]

SecondTry:

I've read your posts on other threads and have no wish to waste my time arguing nonsense with you. You are now on <IGNORE>.

Have fun, big fella!

 

[FreezerBoy]

This thread has run it's course. Closed due to impending flame war.

............................................................................................

Let's try again.

 

[dizzlekush]

Bump for the awesome info. Cant believe this thread sat around for 2 years...

One of the best single posts of all time:
http://www.icmag.com/ic/showpost.php?p=3242078&postcount=30

 

[setaemies]

Wow! What an informational and entertaining thread! A true clash of different mentalities and personalities. Thanks for digging this one up, I think it is reasonable to think that we are not kicking a dead horse here if we continue. Loads of scientific papers, real world experiences and opinions have been presented, but for me at least, theres a long way further to this path.

There's just never a one way for things to be, as most of things seem to be dependent from a given set of circumstances. As an example, world seems very different from the point of view of a bird or an earthworm ..same goes for stealth closet grower and someone who has tens of kilowatts and a warehouse to play with. Both grow dank buds of different quality and quantity, with very different goals and circumstances.

Kudos to all the participants, too bad that secondtry isn't around anymore.

 

[dizzlekush]

Wow! What an informational and entertaining thread! A true clash of different mentalities and personalities. Thanks for digging this one up, I think it is reasonable to think that we are not kicking a dead horse here if we continue. Loads of scientific papers, real world experiences and opinions have been presented, but for me at least, theres a long way further to this path.

There's just never a one way for things to be, as most of things seem to be dependent from a given set of circumstances. As an example, world seems very different from the point of view of a bird or an earthworm ..same goes for stealth closet grower and someone who has tens of kilowatts and a warehouse to play with. Both grow dank buds of different quality and quantity, with very different goals and circumstances.

Kudos to all the participants, too bad that secondtry isn't around anymore.

Haha Gojo/Ganja din/secondtry/Spurr (all same person) would be pulling his hair out right now. let me do a super quick review over the facts here:

Plants do not grow at or near full potential under any known mixture of monochromatic lighting. Its a fact that for cannabis to grow properly you want to supply spectra of red, blue, far-red, UV-A&B and yes, even Green, as well as the orangish area (whatever you wanna call around 600nm) and probably even more spectra. All that ish about "optimized spectra" of lighting is really BS, it is true that L.E.D.'s will activate more pure chlorophyll in a tube (in vitro experimentation to quantify "optimized spectra") per watt, but when it comes to growing big PLANTS (with chloroplasts, ancillary photosynthetic pigments, and an ability to change spectra of absorption) with lots of desirable PHYTOCHEMICALS to be produced , its a whole different story. Also cannabis Pn (photosynthesis) improves as PPFD increases, all the way up to 1500PPFD, so you want to get as close to that as you can. L.E.D.s have issues reaching ANY the above parameters at anywhere near the cost or m^3 coverage as H.I.D's.

L.E.D.s do have use if growing for personal needs only (growing small amounts, and small colas) and living in an area where electricity is costly, making the savings in electricity worth the extra initial $. They also are useful in areas where heat is a real issue, but a 400w hps in a cool tube is pretty dang cool and much cheaper and better when it comes to growth. The one area where i think L.E.D.s have real benefit in the future is for SUPPLEMENTAL lighting (for HPS and CFLs especially), however to my knowledge there is no high efficiency blue or UV l.e.d.s of any sort that get close to similar PPF/w as H.I.D. lighting made currently.

When it comes to lighting, for >95% of all growing applications you want to grow with H.I.D, for those that live in areas where its hot as hell and electricity is a MoFo, then maybe you might want to look at a L.E.D. & C.F.L. combination. So far, as lighting technology stands r.e. horticultural applications, its still H.I.D. FTW, however L.E.D. technology is progressing much faster than H.I.D. lighting AFAIK, so in 5 years it may be a different story.

 

[setaemies]

Thanks for the overview, that pretty much is consistent with my current knowledge of growing cannabis with artificial lights. I understand the use of HID lighting for cash cropping very well, as I own few kilowatts worth of them myself I'm definately not a fan of commercial LED growlights, rather I'm just amazed that how well they work given their efficiency and lack of full spectrum. Whats also amazing that how much bullshit the marketing departments of these LED companies are able to spew out. The R&D side have a lot of catching up to do, if they want to fulfill promises made by sales brochures My interest and point of view on LED lighting is pretty much in possibilities of DIY setups and using them to explore manipulating growth habits etc.

I think that what we can agree on, is that indoor growers want to accomplish maximizing yields with the equipment they have. One of key points would be using hard earned photons converted from electron flow as efficiently as possible, among many other things. That leads me to wonder the following about statements made earlier in this thread and your last post.

What really puzzles me, is why spurr/secondtry preaches about ppfd of 1500. Pn seems to be the maximum amount of photosynthetic reaction a given area or leaf mass can produce, ie saturation point of irradiance, right? So it doesn't describe the most efficient use of irradiance for plant growth. I don't see many people using that much light either. If 600w HPS has output of 1050 PPF, using rule of thumb 50w/sqft for many commercial grows, we have less than 1000 PPFD not even excluding reflector losses. I've seen people getting rock hard buds and awesome yields with even less light. Too bad that this paper isn't publicly available http://www.springerlink.com/content/a3527u6018823x43/

Wouldn't for example this differential quantum yield / ppfd curve describe the efficacy of photosynthesis better?

http://pcp.oxfordjournals.org/content/50/4/684/F10.large.jpg

I guess I have a lot of other questions too, but I'm not really good at expressing myself in english, so maybe later..

 

[dizzlekush]

What really puzzles me, is why spurr/secondtry preaches about ppfd of 1500. Pn seems to be the maximum amount of photosynthetic reaction a given area or leaf mass can produce, ie saturation point of irradiance, right? So it doesn't describe the most efficient use of irradiance for plant growth. I don't see many people using that much light either. If 600w HPS has output of 1050 PPF, using rule of thumb 50w/sqft for many commercial grows, we have less than 1000 PPFD not even excluding reflector losses. I've seen people getting rock hard buds and awesome yields with even less light. Too bad that this paper isn't publicly available http://www.springerlink.com/content/a3527u6018823x43/

where did you get the output of 1050PPF from a 600w HPS? like spurr has already mentioned, there is no accurate way to convert PPF into PPFD, a quantum meter is needed for such measurements. I have the paper you've mentioned (as does Spurr). Let me qoute their conclusion r.e. PPFD (bold emphasis added)

Our data also represent highest mesophyll efficiency (i.e. lowest Ci/gs ratio) around 30 oC and 1500 μmol m-2s-1 PPFD. Values of Ci/ gs ratio increased with temperature higher than 30 oC, which further confirms that a combination of 30 oC temperature and 1500 μmol m-2s-1 PPFD may be best suitable for the indoor cultivation of C. sativa... In view of our results, it is concluded that C. sativa can utilize a fairly high level of PPFD and temperature for its gas and water exchange processes, and can perform much better if grown at ~ 1500 μmol m-2 s-1 PPFD and around 25 to 30 oC temperature conditions. Furthermore, higher PN, WUE and nearly constant Ci/Ca ratio under elevated CO2 concentration, reflects its potential for improved growth and productivity in drier and CO2 rich environment.

That paper and ALL other experiments (at least 3 others) r.e. optimal PPFD for cannabis cultivation, all place the optimal PPFD for cannabis within 1300PPFD-1600PPFD with 1500PPFD being the only PPFD that is constantly within the suggested levels of irradiance. I.e. all known studies where they quantify optimall PPFD for cannabis (which have been completely independent from each other) always end up with results at ~1500PPFD, which is why Spurr insists on 1500PPFD being ideal for cannabis.

 

[asde²]

where did you get the output of 1050PPF from a 600w HPS? like spurr has already mentioned, there is no accurate way to convert PPF into PPFD, a quantum meter is needed for such measurements.

just take it as it is, your grow space is 2m² - your light source output is 1000ppf - there you go, 500 is your ppfd no matter the distance (except for the tiny loss by dust.. lol);
obviously its not accurate because not everything in your room reflects light at 100% but for a good setup room the difference should be less than 25% which is decent enough to start with imo.

anyways, as said before - practically; using 1000w of phlips hps per m² instead of 500w per m² wont double your yield, only your costs...

 

[dizzlekush]

just take it as it is, your grow space is 2m² - your light source output is 1000ppf - there you go, 500 is your ppfd no matter the distance (except for the tiny loss by dust.. lol);
obviously its not accurate because not everything in your room reflects light at 100% but for a good setup room the difference should be less than 25% which is decent enough to start with imo.

anyways, as said before - practically; using 1000w of phlips hps per m² instead of 500w per m² wont double your yield, only your costs...

Nothing you said is even the slightest bit true. not trying to be offensive or start an arguement. just pointing that out for those who are trying to learn here.

 

[asde²]

dont know what you mean, all what i said is correct.

 

[Dave Coulier]

Asde, Im with DizzleKush. Your post has me scratching my head in dismay. These are the times I wish Spurr was still here. He could tell you that you are wrong, and belittle you whilst doing so.

 

[setaemies]

http://www.gavita.nl/v2/nl/nl/GE_lampen.shtml

I have seen multiple sources citing 1050 PPF as a typical output of a 600W HPS grow bulb. If we have a single source with an output of 1050 PPF, then at least we can't assume it will produce more than 1050 PPFD for whole canopy area if used on an area of one squaremeter?

Please bear with my noobish questions, I'm just learning about the basics of photosynthesis and plant physiology. I'd just love to have a deeper understanding of why things work as they do

Would it be possible for you to attach the pdf to your post to be shared?

Another thing that puzzles me, is using Pn net photosynthesis (ratio between total photosynthesis and total respiration) or mesophyll efficiency (ratio between intercellular co2 and photorespiration?) for determining optimal growth. Does it really convert to maximum biomass for a given amount of photons? I'd really appreciate if you could explain this in more of laymans terms.

I'm kind of suspecting, that there is a point of diminishing returns in terms of using HID light, and it might be a lot before 1500 PPFD irradiance is attained? That is, because HID lights produce a lot of photons in the infrared ie, "radiant heat" range. If you could lessen the impact of radiant heat from the light source, maybe then 1500 PPFD for optimal growth would be used more regularly in real world indoor growing? What light source they used in the paper you quoted in your earlier post?

Wikipedia quote:

However, reduction in photorespiration may not result in increasing growth rates for plants.

I hope I made some sense, very frustrating if I didn't

edit: https://www.icmag.com/ic/showthread.php?t=223074

After reading that thread, 800-1000uE/m^2/s makes a lot more sense, I guess spurr changed his mind?

 

[VerdantGreen]

wow- blast from the past

a year on and quite a few more plants grown, the latest LED lamp im trying HGL 126X2 pro
is supposed to be more than 4x brighter than the equivalent light from a year ago.

having actually grown many plants under HPS, CMH and LED i am now even more certain that LED's produce the best quality buds, and the yield per watt was already higher than HPS a year ago, should be even better now.


VG

 

[setaemies]

Thanks VG for dropping by! Your latest grow log looks promising, can't wait to see the end results.

Dizzlekush, could you post links or papers that you mentioned regarding cannabis and different irradiance levels? This was the one you quoted?

https://docs.google.com/viewer?a=v&...MGJiMC00ZTRiLWE4YzctMThjYmE0ZGRhYWE2&hl=en_GB

If I understood right, they used http://http://www.licor.com/env/products/photosynthesis/specs.html for light source and testing? I guess it doesn't produce much radiant heat nor complete spectrum?