HPS vs. MH vs. Mixed Spectra

Couchlock · 02-18-2002, 03:57 AM

hi couchlock here and im here to ask you to think about having 5 lights in your setup. 1 light above, and 1 light on each side of the plants in your grow area. so much extra light has to be good? atleast thats what im thinking. also theres much more available light from all directions. im under the impression that this hasnt been tried before, but if it has can anyone give me a little more insight?

anyways thanks, couchlock

Delta · 02-18-2002, 04:49 AM

many people use multiple lamps. It is recommended by many experienced growers. Multiple smaller lamps can spread the light out better and has the added advantage of mixing lamps to create a more complete spectrum. It's just a more efficient use of the electricity.

If you're thinking of doing this, I would encourage you to mix your lamps. Alternate MH with HPS every other lamp as this has been proven to enhance the rate growth considerably. Versus all HPS or all MH, that is ... especially if you can move the lights on a mover or rotate the plants once a week.

*OzGrowa* · 02-24-2002, 01:59 AM

Quote:

If you're thinking of doing this, I would encourage you to mix your lamps. Alternate MH with HPS every other lamp as this has been proven to enhance the rate growth considerably. Versus all HPS or all MH, that is ...

Delta9420, I have to pull you up on this quote, I have mountains of evidence to the contrary, the study that best illustrates it can be found from EYE lamps, it demonstates the efficiency and completeness of the HPS lamp in growing and flowering plants. The data from the study applies to all HPS lamps Do a search or email Hortilux, its from 1998 or 1999. Two references exist within it that show the futility of lamp swaping, the HPS on its own provides the necessary spectrum at the most efficient rate. From memory it resides online on a .edu server in Japan, but its in English. Several analyses of true spectrum and output of a majority of lamps are provided, reading it will afford you several benefits.

On another level, switiching lamps periodically, in fact slows growth due to the sudden, disruptive spectrum bias. A plant that is being saturated with reds from say a HPS, then suddenly has hose reds diminished drasticly will respondby attempting tor eestablish homeostais as enzymatic processes within the chloroplasts are de-cycled. Two lamps used together are un-problematic, sudden change is not.

Couchlock: its off topic. Start a new thread if you want to discuss a new topic. ...

Regds,

OzGrowa

Delta · 02-24-2002, 04:27 AM

OG,

I definitely did the search. Found plenty of references to Hortilux and EYE ... Although, it would be helpful if you could link me to the mountain. Recently, I have been re-evaluating the lighting spectrum of many lamps for a current experiment of mine. The data I have collected does not support this hypothesis you mention. If you haven't already, check out the UV thread.

http://www.hempcultivation.com/420/s...threadid=19084

Until I find exactly what you're referring to, I wanted to talk about the spectrum for photosynthesis. Because UV really hasn't been proven yet, I'll omit that from this discussion with a note that MH produce significantly more UVx and blues than HPS.

A couple posts, so please, bear with me.

Now, the absorption spectrum of chlorophylls do not absorb the color of light that we perceive, since these wavelengths are reflected. Chorophyll absorbs heavily in the red and blue regions of the spectrum. "Hortilux" and similar light bulbs have a spectral output specifically designed to be absorbed in these regions. But, upon closer inpsection, do they really put out more blues than MH?

Delta · 02-24-2002, 04:48 AM

FYI, for those that care. In photosynthetic plants the pigments are very important. They absorb light energy and enable it to be converted into chemical energy which is used by the plants to make glucose and oxygen from carbon dioxide and water.

An action spectrum relates the rate of photosynthesis to the wavelength of light being received by a plant. For green plants, including Cannabis, the action spectrum shows that most photosynthetic activity takes place in blue-violet and orange-red lights since these are the colours which are mostly absorbed by the main chlorophylls and the carotenoids. Photosynthetic activity is lowest in green light since green light is hardly absorbed at all. The relative absorption of light of different wavelengths by pigments can be shown in absorption spectra. Action and absorption spectra correspond quite closely. Wavelengths of light which are more readily absorbed by photosynthetic pigments cause higher levels of photosynthesis. Ultimately translating into improved plant vigor...

Plants appear to be different colours because of the dominant pigments they contain. The green chlorophylls absorb light from the blue-violet and the red regions of the visible spectrum and reflect green light. All of these spectrums are found in natural sunlight and complement each other when considering photosynthesis. This is the reason why the Hortilux and other blue-containing HPS's exist in the first place. Because plain old HPS doesn't contain much blue or indigo (or UV

). So, I still feel comfortable saying that a plain old HPS isn't as good as a HPS+MH combo ...

It is not accurate to say that using HPS and a MH in conjunction with one another doesn't provide benefits over all (pure) HPS or MH. Also, I could debate other factors that are present in the halid that are not present in the sodium lamps. A pumped up (agro) HPS is still not a MH when considering the blue levels, as well as the indigo and UV.

So, for comparison, check out this spectral analysis of the EYE Hortilux Super HPS lamp. As you can clearly see, the P.O.R.E. of wavelengths in the 400-500nm range is very low. Also, the amount of green light produced is staggering. What a waste ... !@(#&*! marketing.

Delta · 02-24-2002, 04:56 AM

let's look at a pumped up halide compared to the pumped up sodium lamp. Both are Hortilux EYEs and you can clearly see the spectral distribution is much more efficient for photosynthesis in this halide lamp. Considerably less greens and more usable yellow and blue.

Now, I realize we should be talking about pure lamps. Not the high performance ones. But, this was right next to the other pic.

Delta · 02-24-2002, 05:08 AM

with this. The evidence is right there.

HPS+MH provide a more complete spectrum of USABLE light for photosynthesis than just plain HPS or MH used alone. That's all I'm saying. It will benefit the plants and under a controlled experiment perform significantly better than the HPS Only group and/or the MH Only group. I've already done these experiments for myself.

Although, I really didn't need to because the spectral analysis of the lamps is all the data we really need to prove this. Just overlap the first graph I provided with any lamp spectrum to see how efficient the lamp you are choosing will be for photosynthesis.

But, the real test is in practice. It has been years since I first noticed tremendous benefits by mixing standard HPS and MH together like I recommend. The proof is in the pudding. I've been doing it for years. Don't believe the hype, try it.

Oh, and raw HPS and MH bulbs are WAY cheaper than Hordebux lamps ...

Phread O'Hinton · 02-24-2002, 11:19 AM

Interesting stuff, Delta. I've looked into this stuff a while back, and I came to the conclusion you cannot trust any of the "EYE Hortilux" charts- look at the plant absorption curve they provide. I've never* seen any other study, chart, or manufacturer claim huge absorption in the green range.

Anyway, I'm very* skeptical of Hortilux's claims. Not saying that the bulb's bad, or that the enhanced spectrum doesn't help; just that that particular chart is bunk.

My $.02!

*OzGrowa* · 02-25-2002, 12:57 AM

Delta, amongst the growers I know, the current research is beyond consensus that HPS is the sole source necessary for both growth and flowering, further that the use of both is inefficient and counter productive to a good crop. MH lamps are inefficient and are rarely used amongst serious cultivators during flowering. To suggest otherwise is plain silly.

The reference came out a couple of years ago, it was widely circulated on other systems, I was involved in the debate heavily and initially argued your point, only after considerable time spent with this paper was I convinced , check Uncle Bens link-o-rama on another system as he updates it there, it has the experiment link in it (CW,OG). HPS lamps, and I state this again, are all that is needed and supply optimal response across the spctrum. People doing a couple of plants at home can afford to play around with two types of light source and yes they will get an effect, usually as they have added more lumens.

UV has been proven, check Tom Flowwers updated book for references and research, its beneficial and occurs in sufficent amounts in HPS lamps due to the rare earth elements, Hortilux or otherwise. Im not adovcating a particular kind of lamp brand, either should say, that would miss my point of directing you towards the research for a better understanding of plant reponse and the action in this case of the green spectrum of light, it has been proven to keep internode space shorter, it produces the effect that the MH does in this regard but in the more efficient HPS fixture.

Im not sure where you obtained the information from your posts, it reads as if it was trasncribed.

Lastly, I have a simple explanation for this quote.

Quote:

It has been years since I first noticed tremendous benefits by mixing standard HPS and MH together like I recommend

this I suggest, simply results from adding more lumens. Money that would have been much better spent on the adddition of a second HPS lamp.My responses on this issue are closed pending your reading of the paper, Ill email Uncle Ben and ask him also for it so this thread doesnt slide. Misinformation is what I aim to correct on this system.

Regds,
OzGrowa

smokinrav · 02-25-2002, 05:47 AM

Im reading with fascination.

Only thing Ill add is I know growers on this site that yield a pound on a regular basis from a very limited space (10sqf?)with a 1000 MH alone. I know, it says nothing about efficiency, but a pound of pot is a pound of pot, right?

later

Smokin

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