New Grow room Lights

[DrPhoton]

As i stipulated below, there are no advantages i can see over HPS. Perhaps a great replacement for metal halide. But not HPS. Another reason that suggests CMH is inferior, is that most bulb manufacturers claim the luminosity far less than HPS. Luminosity is based on the human eye response which is heavily concentrated in the center of the spectrum. CMH should at least be close if it were more efficient. Especially since more energy is produced in this midband area, producing that white light response. But its not.

If i had the chance to do my lighting system over, i would still choose HPS, even single ended. Hands Down. My next investment will be LED when it starts to become more economically viable.

[DrPhoton]

The photon efficiency is calculated by the photon output, devided by the power (watts) input. So comparing the wattage usage like you did is contradicting the value your represented. In other words.

315w CMH is 491umols ÷ 337w = 1.46 (the extra power consumption comes from heat loss from the ballast)

To take the equivalent photon efficiency from DE Gavita and create a theoreticle comparison we would get something like this.

315w HPS is 575umols ÷ 337w = 1.7 (extra power loss also added)

Thats roughly 30 watt difference. Not huge. But the difference gets to nearly 100 watts when you reach around 1000 watts input.

Digital (square wave) ballasts have been around for years now, nothing new and low frequency is a requirement for the cmh bulb technology. Not a improvement aspect. Older and some current digital ballasts, are still low frequency. The new high frequency ballasts were introduced to combat resonance in HPS bulbs that in some cases caused premature failure. The frequency however has no effect on output efficiency. Any efficiency improvements comes from reduced heat loss from switching circuits in digital ballasts (mere watts). Ultimately the effciency is dictated by the bulb.

As far as heat dissipation, thats another one that i have not tackled yet. The bulb does produce less heat, because of its higher efficiency. But a lot of that light falls outside the PAR range. Which means it goes wasted and turns back into, you guessed it. HEAT!.
Although the heat is not concentrated around the bulb, but spread out some by the environment. So i would bet that there would be very little difference of energy in the form of heat being produced. But im just speculating now.

[Paracelsus]

Thanks DrPhoton, if only they all delivered what they promised. I am thinking that the advantages of MH/HPS would in my application be offset by the need for Air Conditioning to lower ambient temperature in the room below 80's. The figures for Photon efficiency on the 315W CMH were 146 compared to the industry standard 1000w Gravita MH/HPS which was 170 per µmol/s. For the amount of watts used 315 Watts vs over 1000 Watts not a huge effiency difference and very respectable with operating costs for power consumed for light and cooling figured in. I can only postulate these numbers will improve with new data concerning the 630 W Double Ended CMH Low RF technology being marketed now as compared to single ended lamps and higher frequency RF Ballasts of 2014. Quality not quantity aside 3 times 630W DE CMH @ less than $750 vs one Gravita 1000W DE MH/HPS for $425, Ceramic seems the best quality and quantity for the investment and operating costs. I don't really know it just seems that way to me regarding all the different variables.

[DrPhoton]

I could not find any convincing data to suggest the superiority of CMH. Although the price has gone down, it still does not ouperform high pressure sodium. For it to be a economic advantage, it would need to be either cheaper or efficient. So its hard to justify any reason to choose over its counterpart.

All the data i could find that asseses CMH showed no advantage over HPS. Although not entirely scientific, i do respect the data aquired by monster garden. They have the best forward thinking test parameters. They have tested dozens of lights and differing light technologies using methods that are acceptable by my standards. They did not compare HPS directly so the only reliable comparison was with metal halide. But they showed that CMH was only slightly more efficient, with a particular brand of metal halide actually outperforming it. Now its undisputed that HPS is more effective and efficient than MH. So if we take that information as correct, we can assume HPS is more efficient. Another study from utah other than the one i provided also showed HPS as being more efficient. Not by much however. There are even a couple more tests not worth mentioning that showed much the same.

With regards to the light quality, there is actually a disadvantage for the particular type of spectrum that CMH uses. If we go by the mccree curve, which is now out of date and recent studys show to be incomplete. We can see that the higher blue and green percentage is less efficient based on the quantum efficiency provided by mccree. So the upper hand would be given to HPS due to most of its energy being distributed closer to the red part of the spectrum. However as i stated, the mccree curve is not current anymore. This is because of incomplete data. New data shows that at high radiant intensity, the quantum yield begins to be more linear accross the spectrum. Meaning light quality is of less importance compared to light quantity. This is mentioned in the paper i provided.
However light quality does impact plants morphology, with something called photomorpogenesis. The current studys on this have clearly showed the morphological differences between the light bandwidths. However to satisfy each response only requires a small portion of the total capacity. I refer you to my other post #6.5 in this thread on that subject.

I could not find any information suggesting the improved efficiency of the technology of the last two years. Ceramic metal halide is not a new tech. Its been around for 30 years and has merely just been rediscovered for the growing industry.
I tried my best to find anything to suggest CMH as being better, but all i could find was the subjective opinions from people who have them. Which must be taken with a grain of salt, there are so many variables such as genetics, environment, reflectors, height, growing parameters etc. Its just not reliable.

You let me know if you have any information.

[Paracelsus]

DrPhoton thanks for the link update

[Paracelsus]

DrPhoton Hello ! I found all the info you have provided well thought out and fascinating. You wrote it so a layman can understand your logic and reasoning. The link you provided is now dead and I'm contemplating buying 630W DE CMH fixtures. What I thought I understood about them and their light spectrum was basically what you've written relating to MH and HPS but mention CMH lacks. Do you 6 months later feel MH and HPS is superior in the spectrum of light available from the CMH DE 630 W ?

[DrPhoton]

It seems i miss some replies and dont seem to show in my notifications. My applogies for this late reply. I only manage to stumble upon these missed messages when i am back tracking old posts.

Here is a study on greenhouse analysis with supplimental lighting. Wrong interpretation of the material might be misleading or difficult, so if you have any questions feel free to ask. However maybe a PM at this point would suffice.

Study click here

[PigSquishy]

Can you give me some links to the study's (you referenced)... I love reading up on this stuff.. Thanks. The more I know, the better grower I hope to one day be.

[DrPhoton]

I had a quick, however i wont go into to much detail.

They are correct in their understanding on the technology (mostly), but how and what they believe is applicable to plant growth is not correct. I think this happens often with grow light companys. They fail to understand plant biology and incorrectly design grow lights because of such. Even spectrum king uses very inaccurate and poor technical terms for advertising their products technology. Using such terms as "white light is more efficient" is either plain bad understanding or just misleading advertising. White light must be derived from blue LEDS with phosphor coating or from combined assorted LED colors. Although it has higher efficacy (efficacy means the conversion of energy to the desired result) for lumens. It is less efficient because it must be derived from blue or other colors, it cannot be more efficient than the colors from which it is being created from. Meaning although white has higher lumens per watt, its actually less efficient in converting energy to light because lumens is a measure of photometry and is useless for realizing with plant biology.

Now CMH are more efficient and produce less heat compared to MH, however a lot of that light falls outside of a plants photosynthetically active range. Meaning wasted light. Its efficacy for grow lights is about the same but usually less compared to metal halide. Compared to HPS they are not better.

This has been shown with successive studys comparing technologies. Greenhouse studys show LED and other technologies to be less efficient both electrically and cost wise to be used as indoor or supplimental lighting.

[DrPhoton]

Any light other than monochromatic green during the DARK PERIOD will prevent or stop flowering. This is because phytochromes are not exclusive for red light absorption only, they also respond to blue light as well.



Michigan university conducted some pretty interesting studys on the effects of strong blue light on flowering during the LIGHT PERIOD. What they found was that blue slowed down the flowering in short day plants and the opposite for long day plants.
Using red or blue light during the dark phase will cancel any effects from flower initiation. Plants measure the DARK PERIOD from when phytochromes ratio is converted during the light period to when they are reconverted again after the dark period. They do not measure the light period and do not function on a concept of hormone concentration for the initiation process. Once the flower process has started, chain reactions occur which make it diffucult to stop. This is why it takes a while for a plant to convert back to veg.

[PigSquishy]

DrPhoton Since you are good at understanding this lighting stuff better than the rest of us, would you be so kind as to read this and explain it to the rest of us as to how much is fact or fiction, thanks. The article is titled:

CMH or LED Grow Lights? Which is High Performance & Cost Saver? Are You Confused?

https://deals.xpertomatic.com/lesson-page

[PigSquishy]

Okay I did go and do some more reading... according to Ed Rosenthal in his book Marijuana Growers Guide pg 357 under the heading "BLUE LIGHT" he states that during flower the plant is very sensitive to red light, and any interruption in the lighting period with 660 nm returns the Pr back to its inactive state. However Blue Light at 400-450 nm has an inhibitory effect on flowering, and if such a light were to be left on during the DARK PERIOD the plants would continue to grow vegetatively as well. They would produce enough flowers for sexing, but not go into full flowering mode.

I would look back to see when I added the light, what my lighting schedule was, etc... but I no longer have that... but believe me I will take your theories and I am keeping track of them to evaluate this more in the future... One way or another I hope to solve the riddle of why it worked that way.

[DrPhoton]

I have a theory and i am pretty confident on it. If you were indeed using 14/10 as the light cycle, as i had said. For most strains this would be ok, but some still require more darkness to flower. 14/10 is really the crossover point between a plant deciding to veg and or flower. With a particular strain, the plant may decide to flower but then get confused and start vegging again. I believe this is what happend with you. This was possibly exacerbated with the blue light. Blue light has been shown to slow down the the conversion of Pfr to Pr, however less so compared to red light.

[DrPhoton]

Yes it was a typo, it was ment to be 14/10. Just like in the article i referenced it with, discussing about the light protocol (I realised that i had provided the wrong link Correct Link Here).
Outdoor plants traditionally flower at around 14/10, as mine usually do when i do outdoor (I do both in and out). Sometimes the odd one will flower later with 13/11. The whole idea of 12/12 is to allow enough room for this variability. Although you could get away with 14/10 with most strains, it always pays to be safe.
The far red light technique, allows you to send a message to the plant, to tell it to shift its circaridan clock straight away. Typically it takes a couple of hours for this process to occur naturally. This allows the plant to shift its physiological balance to "sleep" phase. Gaining you two additional hours. As you have worked out by yourself, there is no real gain in increasing the light schedule. As the flowering time is increased, countering any benefits. But applying this technique, allows you to take advantage of the added hours and does not take any longer to ripen.

I quite enjoyed your description on your experience with growing and the issue at hand, i did not doubt your experience. However when you are dealing with a phenomenon that cannot be explained by "current" understanding. One must rule out variables before making conclusions, thats the whole idea on releasing papers to the public. To allow people to asses the experiments and protocols used and rule out errors that may have been blindly made (not that inexperience has anything to do with that, we are human, we make mistakes).
But i do look forward to anything further you come up with, but i still feel there has to be some variable that cause this phenomenon. Or something i have missed in my research. But i really feel this cannot be. Plants fall under a category of Short day, Long day or neutral day plants. Its obvious what the SDP and LDP require to flower, but neutral day plants can vary on their ability to flower. Temperature, age, humidity etc. Can all be triggers to enable flowering in these plants. However with SDP or LDP, they cannot flower without the phytochrome balance. I have seen no study under these day dependent plants that show flowering triggered by another variable. It makes it even harder to believe when there has been so many studys on photoperiodism, experimenting all different types of variables to show any exploits or phenomenons that would void this rule.

I wonder were you using 14/10 light schedule ? And i also wonder if there was some sort of disease or deformity that disfigured the plants natural processes from running normally. Anycase its been interesting. Its these types of discussions that test my knowledge and pushes me to study more to have a more rigid understanding.

[PigSquishy]

Note: Google had to correct me to find the book:

Plant Biology by Stern, Bidlack, Jansky (You misspelled the last person's name)

Correct me here if I am wrong, but I couldn't find this book per say, but I did find it online in PDF (64-pages long):
Light Measurement Handbook by Alex Ryder:

http://www.cs.ucsb.edu/~mturk/imaging/Misc/ILT-Light-Measurement-Handbook.pdf

Okay I want to double check on a possible typo you may have said:
"So much infact that, using a light flash technique, you can increase a plants light cycle to 14/12 and still keep a plant in flower"

I am familiar with the Red and Far Red light being used on plants going back over the years, and I am also familiar with Ed Rosenthal's work where he point blank pointed out plants really don't need 12/12 lighting during flower, because if that was actually the case Northern Climate species of plants would not flower until December, but all the crops have to be out by late October because they get snow by then and freezing temps. He even went on to explain how in his early work along with another stated 12/12 lighting which people more or less set into stone as the "standard" from that point forward.

Based off from that knowledge I have always used longer lighting periods of 14/10 during flower, and I do know for a fact that the 60-day flowering cycle has been increased because of it, yes I have noticed increased bud production and growth for the longer period of lighting, but I equally noticed that unless I decrease down to 12/12 or even 10/14 lighting to push for the harvest to finish it can take around 90-days, not the standard 60-days we expect from those same strains. On that note I have been asked if someone could push a longer than 24-hour lighting period such as you suggested as 14/12... or even something longer... but that is where I honestly didn't have any information to answer that question, thus I am very interested if that was a typo or if you really meant to say a 26-hour plant day, instead of a 24-hour day.

On the topic of "revegging... believe me when I say point blank clearly... I would happy show you again if I had the extra plants to spare at the moment to do it because I would love for you and others to try to explain it because I certainly can't. I understand 100% clearly what it is like to deal with newbie growers who think they saw something clearly and honestly just don't have a clue, even when you sit and repeatedly try to explain it to them to understand. I can only assure you I am not a moron, I do have a clue, and I without a doubt know what beautiful very plump buds look like as cola's which I was manicuring and taking very good care of. I also know what it means to see cola's completely disappear, not dry up and die, not fall off, get eaten or some other explainable reasoning, but to literally watch in horror as those lower cola's reverted and disappeared to the point of looking like I turned back the clock. Even when I went to show some others, I had to show the time stamps to prove I didn't just screw up the order of the photos saved at the time of the issues because it was 100% new to me, I'd never seen anything like it before. Like a plump tomato the size of a softball one day, turning around and reversing itself to the point it gets smaller and smaller down to a marble and then a peas size and then doesn't even exist all in a single week's time and no explanation behind how or what the happened... I've been gardening for 40+ years now, and in all my time, experience and knowledge, I can only tell you what I saw and know to be 100% true.

At a future point when I can get back on track again, I will repeat this and I will give you a crack at trying to explain it as you will get to sit and see what I see day by day, a couple of times a day I'll even take photos of it... because I don't have any answers to it, nobody else did at the time and I'd love the chance to maybe end up being the person who turned on some scientific person's interest like Ed Rosenthal into doing further studies to try to explain what happened and why it happens. So yeah I'm looking forward to repeating this for you and will keep a grow journal of it. I'd love to do it right now, but since my brain injury I pretty much lost everything I had growing and am now just trying to get things started all over again. But if you'd like to repeat the experiment for yourself. Here is the light's information:

Made by:
Smart Electrician

Sold by:
Menards.com

Rated for 15-Watts, it has 5-LED's... and it doesn't tell me much else other than it was made 11 / 2012... I did try to find a model number on it, but none of the labels seemed to help me find its model number, its lumen, etc... I did go to Menards.com and try to look it up by comparing what my light looks like to help you, but again they have clearly changed the LED design, if you want I will take a photo of mine off as well as on to try to put whatever into perspective... I've even been thinking in the future I should get a meter or borrow one if possible to do a spectral analysis and also see how many PAR it puts out. All the same it won't really matter because as we both know... at the end of the day "Seeing is believing".

When it comes to the dark cycle I again go with 100% darkness... not the LED light of the clock time, not the red light of a powerstrip glowing in the darkness... NO LIGHT AT ALL!!! How does a person correctly establish its 100% darkness... sit in there for 10-15 minutes with your eyes closed and wait... then open your eyes in the darkness and scan every corner, every bit of everything with the lights all on outside of it and carefully looking to make sure there wasn't even a pinhole of light getting inside of the enclosure. The walls and everything were solid, not like a grow tent someone forgot to zip up all the way one day, when the door gets closed it gets secured and locked for the CO2 enrichment. If the lights are off, I won't go inside even with a green light for any length of time... whatever it is can wait until the lights come back on or unless I'm waiting for the lights to go off to spray and leave within a few minutes after.

Some people see pests as a part of growing, and even allow for leaves and debri to be left on the floors of their growing area... I again take everything 100% seriously, I grow from seed to harvest 100% pesticide and fungicide free, IF the floor gets water on it from the hydro system, I clean it up... if the walls get dirty I wash it off right away... I do not tolerate pests, any outside air which would ever need to be exchanged for the air inside is filtered through a carbon HEPA filter. So I know it wasn't some fungus or mold like Bud Rot that dissolved and ate the buds, it wasn't some pest I was allowing to survive in there, and it wasn't caused by a light leak, or anything else which could explain and account for it. I also know it only took 1-week's time to happen, and at the end of 7days I pulled the lighting in hopes of stopping the process, but it was too late, the plant's lower half revegged... and I know this to be a fact despite knowing what you are saying about revegging taking much longer to be 100% true. Thus why I thought I was actually onto something to help me shorten the revegging time, and when I tried it i killed 1/2 of the plants.