I might have come on a little strong in my previous post. It was late and I should have been asleep, lol. If so... apologies.
Well, of course some oscillating fans would be fine with some T5's compared to MH's that require ducting,inline fans,etc.
I wasn't stating that a GR containing MHs didn't require a cooling/ventilation setup. Only that for T5 setups, some air blowing across the ends of the tubes was important (for the reasons I specified). As the post I quoted you from was - or at least appeared to be - discussing them in regards to aquarium setups, I thought it worthwhile to mention that. Incidentally, although many aquarium setups have fans/cooling on MH, that's for preventing the heat they produce from interfering with the life in the tanks (which they may or may not do, depending on the setup and ambient temperature); the MH will still perform within spec (for the most part) whether or not they are cooled (unlike the T5s, which do produce enough heat in reflectorized setups & tight spaces to have performance/longevity issues without it). A GR setup is different and, yes, heat-removal from MH setups is often an issue and more frequently than in an aquarium setup. They obviously run hotter than T5s (although T5s
do produce heat).
I wouldn't think that an oscillating fan would be the best way to cool T5s; it only directs the main focus of the moving air across the ends of the tubes (which seems to be the most important part to cool) part of the time, whilst directing air across the larger central region (which one does not wish to over-cool) part of the time as well.
Those Actinic bulbs state their PEAK, I was just giving a range in reference of what the plant needs.
Sorry... I thought you stated
Stoned4daze61 said:
they are spectrum specific like the LED's
and
Stoned4daze61 said:
basically a T5 fixture with the benefits of being wavelength specific just like Expensive LED's
which I found to be somewhat misleading (and still do).
I'm probably wrong, but I don't think the Kelvin ratings have much to do with the issue here.
Actually... I
think I might agree with you in part, lol. HPS color temperature ratings, for example, do not tell their full story, which is that they produce a fair amount of their illumination in wavelengths that aren't especially helpful to the grower - which, incidentally, partially account for their generally high lumen ratings, as many of those wavelengths are ones that the human eye perceives as being strongest (where absolute levels of radiation across the spectrum are equal). Luckily for growers who use them in flower, they produce enough overall illumination that their outputs in the pertinent wavelengths is still reasonably high. (Not
great, I understand that.)
I agree that mixing bulb-types can be beneficial. In the past, I've used various types of fluorescents in combination as supplemental lighting to help "fill-in" the spectrum in what I hoped gave more overall PAR (yes, I've used fluoros for the entire lighting setup before too, although I don't like to admit it
). A long time ago (couple decades) I found running approximately 25% MH / 75% HPS to be beneficial. And I saw that 430-watt C&C ballasts running (if I remember correctly) Planta-Ts with their immediately recognizable (it came up first when the ballast was powered) added blue to have merits for the (relatively) small size - the plants seemed exceedingly healthy and had pleasantly short internodal spacing.
I've recently purchased a small (400-watt) HPS bulb that is supposed to be high in PAR. It is one that I have never used before. Therefore, I intend to run it by itself, at least for flowering; I may instead use an old MH for the vegetative phase, starting it at 250 watts and then running it at 400 watts after the plants have grown a bit (I have not decided). Part of me wishes to run the HPS bulb all the way through so that I may observe its performance - or, possibly, lack of it, lol - in the vegetative phase, how the internodal spacing looks, et cetera. But another part of me wishes to run it only in the flowering phase so that I might have a bit of a baseline (in flower) to later compare its performance after it has "a few" hours on it. Like I stated, I have yet to make up my mind.
I'm going to start the grow within the next few days and may journal it here. I haven't seen much mention of the bulb here - and I feel like I owe the
420Magazine community a journal in any event.
Now, let's say you said, "Well, I found a 5,000k CFL that has a GREAT full-spectrum rating (CRI) of 95+
That would be a remarkably unlikely occurrence, lol. I care little for the color rendering index in regards to growing cannabis. In truth, if I wanted to view the plants in anything approaching their "normal perceived colors," perhaps in order to post a decent picture of them here, I'd be
FAR more likely to just spend a few seconds adjusting the white-balance on my camera (or just flip the HID off for the photo).
well, that just means that the light being emitted is more broadly distributed across the visible light spectrum.
Err... Not exactly, lol, but I agree that CRI has no place in determining the viability of a light-source in regards to growing cannabis. (For that matter, it has some pretty pertinent issues in regards to what it's
supposed to be for, lol).
Colored LED's emit light at a specific wavelength, so that's why you don't often see Kelvin ratings
Yes. Incidentally, I will allow that many fluorescents are somewhat "spiky" in their spectral charts - just not in the same way that individual LEDs are.
And that's why this thread was started.
Actually, now that I stop to think about it...
AcesFull said:
Now to the questions:
Does MH at the same wattage outperform HPS in that I'll get more clones per month by switching?
Would jumping down to 600w MH slow my current growth rate?
And (again) my apologies to
AcesFull for wandering so far afield. I'd like to think I wouldn't have done so had he not already received enough information/opinions to have some ideas.
It doesn't appear that much research has been done on which EXACT wavelengths are most absorbed by cannabis. You can consult the GENERIC photosynthetic response graphs, that show the peak areas of light absorption . . . but the graph isn't specific to cannabis.
Agreed. A lot of research has been done on PAR and its affects on plants in general, and there have been experiments on specific plant-types - but not, to my knowledge, on cannabis. I have no doubt that some LED manufacturers/sellers have done
some testing - but I take that with a grain of salt because I tend to suspect any purported research done about a product-type by the person who is trying to sell me a product of that type and because I strongly suspect that if any of them ever make any exciting discoveries... that they'll keep the actual specifics of their findings to themselves as long as possible for obvious capitalist reasons.
So for the most part, we are limited to the findings of growers. Many - but not all - of whom aren't known for their experimental method, for properly keeping a "control group," for only testing one change at a time (and then later, if the results seem to warrant it, trying different changes in combination), et cetera. For one, it is difficult to not wish to see all of our plants produce the best that they can (in all aspects). Additionally, many of us still make the occasional "dumbsh!t stoner mistake"
- and it is difficult at that point to immediately scrap the "experiment" and start fresh simply because it was contaminated and any results would be suspect at best, unusable at worst.
So the question still stands: when will we finally have studies specific to cannabis regarding which EXACT light wavelengths are best.
Hmm.
I suspect eventually we'll find that it varies by strains, depending on factors such as leaf color.
Agreed, there will likely be some variance. Whether
small changes in traits will prove to be enough to show significant difference in response curves... IDK. But I don't consider it unlikely that there will be measurable differences between, say, a pure sativa and a pure indica (if any
pure strains can be found for testing by the time researchers have determined the general cannabis PAR characteristics to "a few decimal places" (so to speak) and get around to wondering about specific strains.
And we'll eventually find that certain spectrums (such as 280nm UV light) might have benefits that we are only guessing at now. For example, the 280nm range might spark a "tanning"-type stress response from the plants, causing more resin production for protection from that light.
That is nothing new (although I cannot remember the exact wavelengths ATM as I haven't had my herb yet, lol - I'm having trouble just trying to spell properly). Many have found anecdotal evidence of such, especially with strains who have strains that were naturalized under high-altitude conditions in their genetic makeup. I am not sure about empirical evidence, mind you (see my comments about some cannabis growers' - including my own, more times than I'd care to admit - approach to the experimental method, above). But there has been enough that I believe it and would like to see some specific results for specific strains under properly-controlled experimental conditions.
and since LED are becoming more efficient (I think they double their efficiency every three years), it'll soon be a no-brainer.
Yes, LED development seems to be following Moore's Law (in power/efficiency, if not in price) to some extent. Although "soon" is a relative term and depends on several factors (the continuing legalization of cannabis for medicinal reasons opening up a larger and larger "legitimate" customer base, for one. The feds relaxing their persecution (and occasional prosecution) on cannabis researchers who enter the research phase with an open mind instead of with intent to prove some form of harmfulness of cannabis use would be another... if/when that ever happens).
