New Grow room Lights

[oldjarhead100]

some of you know I will be building a new grow room . I plan on enough room so I can work around the plants and was going to use a light mover to move my 1000w hps back and forth with Leds to fill in the full spectrum has anyone used a light mover before. Or would it be better to use more lights.(not what I want to do .my electric was 500 last month) any Ideas would be appreciated Thanks

[DrPhoton]

If you are wanting to increase yeild, you will have to invest in a light system that outputs more light flux energy.
Iv seen all sorts of setups that try to make more efficient use of a particular light source, but ultimately the only thing thats improved is the efficent use of space. One example is verticle grow setups. They yeild about the same or less as typical setups, but they make much more efficient use of the available space.
I have also seen really well done rotation grow systems that rotate plants around a verticle light source.

https://forum.grasscity.com/threads/rotating-plants-method.1161985/

The problem is that the light source is the limiting factor, no matter if you increase the surface area exposed, the amount of energy leaving the source will be the same that reaches the plant. You really only distribute the energy in a more even fashion, however i can see some negative qualitys to this also.

If you want to try increase your yeild with the same power demands, you will want to look into plant training. Utilizing the available light as efficiently as possible by controlling your canopy and plant structure. The most efficient system there is, is likely sea of green. The more plants you have, the shorter your veg time.

[Sammy]

Hey oldJarhead watch grow boss videos on light Movers very informative and the guys is a riot. You can effectively double your yield with a light mover and that 1000 watt HPS for just a few dollars more per month I think you will like it.

[DrPhoton]

I have seen no evidence or theory that suggests increased yeild. Take a 10x10 SOG canopy, with a 600w light covering 1/4 at any one time. No matter the speed or duration of the coverage, the amount of light received by each of the plants, would be the same if the light covered the entire canopy at once. Its the conservation of energy. Its always the same.

I have read of so many that have taken the plunge, only to regret it.

https://www.thcfarmer.com/community/threads/1-year-with-light-mover-what-a-waste-of.13204/

[Tryitagainsam]

I like my two 600 hps lights as they cover a larger space and elec isn't bad. Lec's look great if your in it for the long run. 2 sents

[PigSquishy]

Well if you like to Ed Rosenthal, a widely respected scientific type of person, Ph.D, etc... on cannabis he says two 600-HPS lights will yield more than a 1000-watt HPS in the Grower's Handbook. While I do agree your light source is your limiting factor I bought a top LED and so did a friend of mine... in fact his is suppose to be more powerful than mine, but side by side they appear equal for the amounts of intense lighting they put out. I went out and bought Orca for the walls, he put up Mylar... I had better temp control and I had better yields and not one single issue with hot spots on the leaves or anything else. Overall I still look back and would invest in it because it more than paid for itself in a single grow.

[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.

[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]

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.

[DrPhoton]

LED manufacturers use incorrect testing parameters and incorrect advertising. They are severely inconsistent compared to eachother and a lot of products offer no efficiency benefits over traditional HPS.
They advertise the spectrum, comparing it to the incorrect chlorophyll disolved in solvent charts. Completely ignoring the Mcree curve. Whats highly amusing is with a video by kind LED in which they detail the mccree curve but then completely contradict it with a chrolophyll solvent chart.

Mccree Curve

Chlorophyll Solvent Chart

LED efficiency is not stagnant, their efficiency has been developing over the years, this is called the haitz's law. Its only of the last decade that LED technology has really seen its place as the dominent light source due to lower cost and efficiency.


Green LED's have had poor efficiency compared to RED/BLUE. The reason behind not using green in LED grow lights is not because of plant absorption sensitivity, but because its less productive using a lower efficient spectrum LED.
Recently green LED's have now caught up, allowing its use in grow lights. Spectrum king is one of the first to adopt this and has full spectrum LED products. Knowing full well about the plants spectrum sensitivity, providing highly efficient and field tested yeild per watt.

[oldjarhead100]

Thanks so much all for the information. My intention was to have room to work on the plants where they are and not have to drag them out to trim or tie up or down ect. so the room would be about 8 to 10 feet long and about 6 wide . I know that 2 600 w hps lights are better than 1 1000 w light .I didn't know that when I started. and to incorporate some co2 into the grow .

[DrPhoton]

Thats a decent size, i do have to add that if total light coverage is limited because of hang height, a rail system will improve yeilds from increasing plant count. If the ceiling is high enough for the light to cover the intended area, that would be just as effective, less complex.

Good luck

[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

[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.

[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.

[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 ?

[Paracelsus]

DrPhoton thanks for the link update

[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]

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]

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.