'eadStash

This thread is quite a ride....

Originally posted by OzGrowa


Based on the red light to far-red light ratio(R/FR ratio) it can be determined whether plants will have elongated or controlled growth. High R/FR values indicate controlled growth, and low values indicate elongated growth.
The R/FR ratio of the XW type of HPMVL, the MHL and the high color type of HPSL are all associated with growth elongation.

HPSLs, which have a large red light component, induce elongated growth, and are therefore used for cultivating herbage crops in plant factories of the closed system type because of their high efficiency. HPMVLs, and MHLs have a large blue light component, and therefore induce growth suppression. However, MHLs are currently the only high wattage lamps that can be used on their own to induce relatively good quality growth.

To achieve adequate growth in indoor shops, MHL 3,500 K may be recommended because of the high R/B ratio, R/FR ratio and light quality balance. For maintenance growth and esthetic displays, MHL 6,500 K can be recommended because it enhances the green color of leaves of ornamental plants. MHL 4,500 K or 6,500 K can be recommended because their R/B ratios are associated with growth control. If HPSL 2,500 K is used, ornamental plants may become overgrown indoors because both the R/B ratio and R/FR ratio lead to the optimum conditions for growth.


The HPSL 2,500 K lamps provide the highest combination of light quality balance, R/B and R/FR ratios, and lead to superior plant growth characteristics. Since many factors relating to plant growth and light irradiation remain unclear, we hope that this report will be a useful point of reference for the research and development of artificial light sources for horticultural applications.


I find this to be a good representation of the study (for those of you not wanting to read the whole thing. Though I would defer to say that these studies were done on plants other then the mj.

There are many other factors to consider in the MH vs HPS ordeal. One might possibly be the genetics of the plant. Let's say for instance a plant has spent a majority of its lineage in a red heavy light spectrum. That plant might become more responsive to the red end of the spectrum than one that has spent its lineage in a blue light dominant environment.

CC, bless you for even considering an experiment. But there are alot of control factors to consider. The independant and dependant variables might be too tough for one man alone. (If you are serious PM me and I'll list some of the the varibles you need to control for)

One of the main things to consider when reading these articles is the type of plant that they are testing and how they are testing. We are looking for a special kind of biomass. Yes a MH will provide ample biomass, but not the specialized type that we seek. It appears in the life cycle of particular plants that a certain type of growth may be wanted or perhaps a particular shade of leaf or flower desired. From this study we can see that these factors can be manipulated by changing the R/B and the R/FR ratios. I am sure this study can be factored into mj growth, but at what level. From what I have seen in 10 + years around grows I just know from experience that HPS lights create the best specialized biomass (buds). Though this study is not directly correlational, it one that is worth consideration. Thank you Oz for bringing it to our attention. I'm sure there are other controlled studies about the growth patterns of a particular plant with respect to a certain spectrum combo. But if you are looking for light effects on specialized biomass then the place to look is the online grow sites. If you look around there is no denying the larger propensity of "high grade" biomass (buds) grown under HPS. (seriously, look around)

To flip sides MH can and will produce light spectrum to grow and flower a plant. The specialized biomass that we seek is not optimally produced with this type of light. However, it is produced. According to this report, growers who are wanting shorter plants may like the results of a lower R/B ratio. Again genetics may dictate nonetheless.
Just my $.02 (hell, that's almost a nickles worth of my )

OzGrowa

hello 'edStash I am just glad I was able to get to and post the second part and conclusion to the study, no one else seemed to want to post or discuss it as it didn't support their arguements and mistaken position in this debate, fair enough on one level (no one wants to appear wildly incorrect after challenging Oz ) but disingeneous on another, still we have it now so we can hopefully move beyond the simple and naieve idea of a static, unchanging, unadaptive plant. I think a lot of people negelected the idea of a living organism and charged off reading botany books, research papers and other miscallany. Its a plant people, it adapts



That is absolutley correct from my understanding, advantageous adaption of chlorophyl cells (collumns, rows) is indeed what I believe happens, marijuana it is known loves the reds and far reds, the HPS lamp and especially the modified HPS (Phillips SON_T and EYE Hortilux) delivers much more useable reds and far reds than any MH lamp so, as we see in the research, we see in our growrooms, bigger and more healthy flowers on our plants. Its an idea that someone mentioned once, Im not sure if he understood the importance of what he was saying when he mentioned it but it aired it anyhow, he mentioned noticing the changing and thinning of the leaves under the HPS, that indeed is what occurs, the plant adapts to its environment, not as it was suggested as a negative factor, but as a positive factor. Not every phenotypic change is negative, that door swings both ways.Dont forget this plant is a weed....weeds are good at that adaption thing


Well said and correct, without Cannabis specific research a large part of whats published is only useful as a guide, a tool to aid further partial understanding, we then need to go and see the real life "....weak ass experience...." as some misinformed troll put it, to see the real picture. Grow sites offer the best reality based appraisal for lamps and a simple look through the VI gallery here or even at other systems readily shows you how successfull marijuana grown with HPS lamps is. Take a look at the 70 watt or 150 watt HPS grows by absolute newbies, they produce fine marijuana using these lamps.

Biomass is exemplified with the HPS, to suggest otherwise based on the thousands of pictures and grows that get posted is plain stupid, sure if you want to play around with lamps, change lamps, hang multiple inefficient and counterproductive sources then go for it but for the small closet grower and person starting out the HPS lamp is a far better and more productive option, for the commercial grower it is too anyone burning 10 , 20 or even 30 thousand watts is better doing so with HPS, its a given in the business and to argue this point is a prime indicator of both the cultivbators level of expertise and indeed the extent of their operations

MH lamps are great for taking pictures as I like to remind people, they also have application for certain inefficient grow techniques as the lacking and necessary ratios of n/fr and will contort and reduce advantageous nodal space, lowering yield but controlling height due to inefficient training techniques and practises. I only see a use for such lamps in commercial operations where a minute percentage of this type of light is required, say in a cluster of 5000K of pure HPS we may use 1 x 400watt MH simply for a bit of extra blue but as a sole light source the MH clearly doesnt cut it when we pair it up to the researched, and published HPS lamp.

Oz

__________________
Click on this thread for marijuana flowering from start to finish. My growroom can be found Here! . Please also take a moment to read The System Rules too. Our online grow-bible can be found Here. Discussions on the politics of Marijuana and the latest news, Medical Marijuana research and updates in the War on Drugs are all at our sister site Marijuana.com. Wondering what Im smoking ? Click Here to find out

GrowWeevil

Personally, I am happy to see the debate continue. I would like to propose the thought that given mj's genetic structure, the plant's response in one strain/phenotype could tend toward more red, more blue or more balanced light being the preference. Wow, I confused myself there. ;-) What I am saying is that I have only sampled different lighting a couple of times and with a fixed number of strains/phenotypes. Is it possible that (and I use this purely for example purposes) a Bubblegum could prefer more blue light in it's lighting diet, a WW more red in it's diet and a NL5 prefer a mix of red and blue to produce denser and more potent buds? This is not a leading question in any way. I have not performed the tests across multiple strains to ascertain the answer. But, I know many of you have a ton of experience so it's quite possible one or more of you have done so to the point of statistical validity.

Anyway, I was just thinking how comical it would be (in hindsight) if we were to determine different strains have different lighting preferences.

GW

P.S. Oz - glad to see you have stayed on board in this converstaion. If everone will take a deep breath and remember we are here to learn and not bash one another then we will advance our position. Me included. :GW steps down from the soapbox: ;-)

__________________
"don't hesitate, don't be greedy, don't look back" - D

OzGrowa

I almost forgot a link to some of my pictures to further backup my arguement, I know some of you think its silly to use a highly functional garden that is growing marijuana to support an arguement but here is mine anyway and an explantion, with pictures to support the reason I speak as strongly as I do about the advantages of the HPS lamps.

You can see I use my HPS lamps for growth, flowering and for breeding purposes without any of the claimed deficits that apparently occur as a result of doing so.


Click Here for my growroom and mother room.

Oz

__________________
Click on this thread for marijuana flowering from start to finish. My growroom can be found Here! . Please also take a moment to read The System Rules too. Our online grow-bible can be found Here. Discussions on the politics of Marijuana and the latest news, Medical Marijuana research and updates in the War on Drugs are all at our sister site Marijuana.com. Wondering what Im smoking ? Click Here to find out

deviant

Are we still debating this?
Because as far as I'm concerned the debate is defunkt.
My yields have never been better since I switched over to purely sodiums.
Just my experience,
dev