HPS vs. MH

[thelastpirate]

I vote t5 for veg, there are 8 lamp 4 foots that put out over 40k lumens, and you can practically sit the light barely above the plants. You can use your own combination of 3000k and 6500k lamps to achieve whatever balance you want. They don't need air cooling. They use less energy than the most comparable size of hid light which is a 400w, and i mean way less, if you compare a mag ballast hid to this fixture. Plus, they are maintenance free, can run forever without having bulbs go bad a lot, bulbs are cheap, the list goes and goes.

As for flowering, you can't beat the old hps bulb and an air cooled hood reflector. Get the biggest and most expensive you can afford to run and keep cool in your space. From what I have seen firsthand and second, once you get good at cultivating crops from indoor grows, the only ways to get better yields is better light and temp control.

My choice from your bulbs would be the hortilux, given that is all of the three I have used before. Great bulbs though.

Floro's are great for seedlings and vegging. Yes, they are good for growing what we are growing, as evinced by the many who use and swear by them. They are capable of producing good bud.
But are they optimal? No. Are they cheaper to operate? No. On your electric bill, you can see that you are paying per kilowatt/Hour (1000 watts per hour) Your average home computer is between 450 and 525 watts. Watts are watts, no matter what is using them. A home computer that uses 450 watts costs about the same to operate as a 400w MH or HPS light. So to say that a 400w flourescent fixture uses less power than a 400w HID is kinda silly. For example: A 400w flourescent produces 40,000 lumens, and a 400w HPS produces 55,000 lumens. Which costs less to operate? Neither. They cost the same per Kw/Hr. With a HPS,however, you're getting 15,000 more lumens. That makes HID lighting more efficient in terms of light output per watt.

1st choice - 400 Watt GE Lucalox PSL/XO HPS $62
Specs: 28,500LH, 56,500 Lumens, CCT 2100K, Base Mogul
2nd choice - 400 Watt Eye Hortilux Enhanced HPS $85
Specs: 24,000LH, 55,000 Lumens, CCT2100K, Base Mogul
3rd choice - 400 Watt Enhanced HPS Light Bulb Osram Plantastar $65
Specs: 32,000LH, 55,000L, CCT2000K, Base Mogul

Lets start with bulb life. A typical MH or HPS bulb has an expected lifespan of 18,000 to 20,000 hours. A CFL has an expected lifespan of between 6000 and 8000 hrs. About HALF that of HIDs.

Now lets compare the 3 choices:
They all have great lifespans for the bulbs, and are all within 1000 lumens of each other and they are within 100 DegK in color temp of each other. I'd say they are really close to each other performance wise. The only appreciable difference that I CAN SEE, is price. Is an additional 1000 lumens worth the $20 extra for the Hortilux?

Light is light across the spectrum on a sliding scale. A given bulb will produce XXX amount of light equally across the range of the spectrum it's designed to reproduce. 2100 degrees kelvin is the same color temperature no matter what the light source. It can be floro, HID or a flashlight for that matter. The only important values here are the light output in lumens, and the spectral range of that light output.
"Conversion" type HIDs have an added element that adds another frequency range to the bulb. However, "most" conversion bulbs have about 10,000 to 15,000 fewer lumens. Is the loss of light output worth the added color range (light frequency)?
Unless a company has come up with a way to produce a light thats more "usable" to plants than other companies, then light is light. The marketing boys are the ones who stick labels like "Advanced Agro" or "enhanced", or the "Your plants will love this light 'cuz it cost more" on thier bulbs. The reality is that the only differences in bulbs is the quality of light they emit. And by quality of light, I mean the characteristics of the light (intensity/color temp). Remember, 2100 degK is the same no matter where it comes from.
In short, while you can certainly grow pot with floros or CFLs, and do a good job, HID lighting is alot more cost effective, and greater in intensity.
I am not saying that Floros or CFLs are not good because they are. I am saying that watt for watt, HIDs far outperform any floros whether they are CFLs, T12, or T8s. To say that floros cost less to operate is nonsense. And given the choice of 2 bulbs with exactly the same characteristics of light, buying the one that says "Enhanced" (or whatever term they use to make you THINK it's better) is just throwing money away.


Just my opinion.......................I COULD be wrong.

 

[thelastpirate]

Buy any 400 hps and just put a 400mh bulb for veging and its all good.

I do that with a 1000 watter. Oh and for a few years now.

Yep!!! It's true. Not recommended by alot of people, but I do it too. HPS fixtures WILL burn MH bulbs. (But not the other way around)

 

[born2killspam]

I've looked at the outputs from standard hps bulbs, and from a Hortilux EN through a spectrometer, and the Hotilux definately has a MUCH more expansive output spectrum..

 

[thelastpirate]

I've looked at the outputs from standard hps bulbs, and from a Hortilux EN through a spectrometer, and the Hotilux definately has a MUCH more expansive output spectrum..

Due to the added quartz or ceramic element in it that produces the extra light (color) range no doubt. But how about the light output in lumens? The "enhanced" bulbs I've checked out all had a broader spectrum of light true enough, but every one that I have personally seen had a significant loss of light intensity as a trade-off. There are some that supposedly do not have a loss of light, but I've never seen one in person. I have bought several different ones in hopes of finding "that magic bullet", but after using each of them for a few days, I went back to the old tried and true MH and HPS, each to thier own use. I am one of those who will try to fix what aint broke, and try to improve what has worked for others for years. I ended up giving away my "enhanced" bulbs because they just weren't as bright as thier counterparts. Not saying a good conversion bulb doesn't exist, just saying I aint seen one.

 

[born2killspam]

Ahh, but remember lumens and PAR watts don't correlate.. The only thing the number of lumens/watt can really tell you regarding horticultural efficiency is roughly how much energy/Watt is wasted as heat > ~800nm..
Enhanced bulbs have energy spikes in parts of the spectrum that 'humans' see as less light per watt (therefore less lumens/watt), but plants on the otherhand see it as more light/watt (More PAR Watts/Watt).. Ironically plants are least sensitive to the range of visible spectrum we are, and vice versa..
And it gets complex when you need different PAR sensitivity curves for different growth stages.. Plants are more sensitive to the red area of the spectrum in flowering than in vegitative growth, and vice versa.. There are integration tables floating around the net for conversions based on plant type and growth stage.. (Yes every plant has its own sensitivity curves).. These are typically based on µEinstions though, which is more of a photon count than Joules/Watt thing..
You'll see alot of variation in plant sensitivity curves for this reason, while all lumens/Watt graphs look pretty much exactly the same.. Through all the variations though, the one common thing is that they never really correlate well to lumens at all..

 

[Seamaiden]

It's that spectrum shift thing that's gonna get me. It seems that the best way to do things really is to split between metal halides and high pressure sodium for vegging and flowering respectively. I have to say that in many regards growing corals is easier.

 

[born2killspam]

That is a good solution, but really it would be best to keep some combo of each through the whole thing.. Laboratory grows often use varying amounts of hps and mh with a light diffuser below that mixes up the spectrums.. It has something to do with auxin regulation.. I read somewhere that redder spectrum early helps the plant adapt its sensitivity to autumn lighting.. (eg: Pure 6500K MH etc early will make the plant utilize pure hps less effectively per watt than if it recieved some red spectrum in early growth), and blue spectrum addition during flowering helps keeping stretching at bay.. Its pretty common knowlege that MH is king if you want stout plants with short internodal length..

 

[thelastpirate]

It's that spectrum shift thing that's gonna get me. It seems that the best way to do things really is to split between metal halides and high pressure sodium for vegging and flowering respectively. I have to say that in many regards growing corals is easier.

Excellent analogy with the coral. Just last week I was thinking about how Bud formation and coral growth are basically the same, each a colony of independent polyps(calyxses).
born2killspam is right about having a mix of HPS and MH (From everything I have read). MH is good, HPS is good, a combination is best. Like I said, I am definitely one of those who will try and fix what aint broke, and the tried and true method of using MH for veg, HPS for flowering is not broken, so I just had to remind myself that it didn't need fixing. I have tried several "Combo" bulbs, but every one I have tried had less light, and the light loss did not offset the benefits IMHO.
Par really is the way to judge the light when dealing with photosynthesis, but the light emitted by the bulb still doesn't change. Using lumens per watt is something most folks can get thier minds around, PAR isn't so easily understood. A given bulb will emit light in a given range, both visible and not visible. The amount and color temperature of light that a plant needs for each stage of develpoment is widely known, having been established by those who grew before us. What this discussion relates to here is us trying to reinvent the wheel. And thats a good thing because if there was no experimentation, there would be no progress or improvements.
But, and this is MY opinion only, conversion bulbs would only be ideal IF they had the same output intensity as thier single MH or HPS counterparts. The loss of light, (and the expense of them) to me do not justify switching. I have spent well over $200 trying to improve on whats always been accepted practice. It just didn't work for me.

 

[thelastpirate]

Ahh, but remember lumens and PAR watts don't correlate.. The only thing the number of lumens/watt can really tell you regarding horticultural efficiency is roughly how much energy/Watt is wasted as heat > ~800nm..
Enhanced bulbs have energy spikes in parts of the spectrum that 'humans' see as less light per watt (therefore less lumens/watt),

I agree to a point. There are spikes in the frequency range of light a bulb emits, but that bulb emits the light it's designed to reproduce equally. A 40,000 lumen bulb will not emit as much light across the board, visible or not, as a 55,000 lumen bulb. So in that respect lumens are a good measuring stick for comparative purposes.

 

[-=4:20=-Guy]

Why is this a Question still?

Veg is best with MH, Flower is best with 30%MH 60%HPS (The same Ratio of all the HPS Agro bulbs)

Now if you can only afford one bulb get an Agro bulb and the 30% "enhanced" spectrum (the spectrum of a MH) will make plants veg great but with 30% efficiency of an equally powered MH.

 

[born2killspam]

I agree to a point. There are spikes in the frequency range of light a bulb emits, but that bulb emits the light it's designed to reproduce equally. A 40,000 lumen bulb will not emit as much light across the board, visible or not, as a 55,000 lumen bulb. So in that respect lumens are a good measuring stick for comparative purposes.

I'm not sure if you understand what I mean by sensitivity.. Imagine 2 monochromatic light sources like LEDs, one is 10W @ 450nm (blue), and the other is 1W @ 560nm (yellow).. Which do you think outputs more lumens (appears brighter to us)? The answer is the 1W yellow one by a tad because we see 560nm light just over 10x as efficiently as 450nm.. Which one yields more PAR watts (appears brighter to plants)? Well since the average plants see 450 & 560nm with roughly equal sensitivities, and we have 10x as many blue watts, there is roughly 10x the PAR watts in the blue light..
'Across the board' goes without saying.. All bulbs' spectrums are analyzed across the board.. They integrate the number of watts output at each wavelength across the entire spectrum of wavelengths, then superimpose that onto whatever sensitivity coefficient curve they wish to correlate to, and multiply..
The difference is analogous to Arnold & the Predator.. Predator was sensitive to infrared, not visible light.. The shift may not be as drastic with plants , but the concept is the same..

 

[Seamaiden]

Lastpirate and born2kill, et alia, are there any known issues, such as loss of lumen or efficiency, with those ballasts that are supposed to run both bulbs?

 

[born2killspam]

Ballasts come in different types, and the types vary in efficiency, but that isn't bulb oriented..
Switchable ballasts come in varying degrees of complexity, and depending on the innerds of that, you can get rapid lumen loss, shorter life etc if you're using the bulb type it wasn't really intended for..
A full-out switchable ballast should have separate taps off the secondary for MH and HPS because they run at different ideal voltages, but these are within tolerance..
Many cheaper switchables are just hps ballasts with a switch on the ignitor though.. This means that your hps would work fine, but because hps uses a larger capacitor you're going to be overpowering your MH (by about 25W/mF iirc).. Not a big deal since hps have bigger cores they can handle that without risk, and MH bulbs can be gotten cheap.. Other switchables basically split the difference in capacitor size.. This I don't like.. The best ones obviously have multiple capacitors, multiple lamp outputs and a switchable ignitor for the hps..

Oh yea, btw when a MH bulb is slightly overpowered (by larger capacitance) it will produce more red spectrum light.. Unfortunately along with reducing bulb life, its going to make alot more noise.. The bigger the core, the less noise you should get..

 

[thelastpirate]

I'm not sure if you understand what I mean by sensitivity.. Imagine 2 monochromatic light sources like LEDs, one is 10W @ 450nm (blue), and the other is 1W @ 560nm (yellow).. Which do you think outputs more lumens (appears brighter to us)? The answer is the 1W yellow one by a tad because we see 560nm light just over 10x as efficiently as 450nm.. Which one yields more PAR watts (appears brighter to plants)? Well since the average plants see 450 & 560nm with roughly equal sensitivities, and we have 10x as many blue watts, there is roughly 10x the PAR watts in the blue light..
'Across the board' goes without saying.. All bulbs' spectrums are analyzed across the board.. They integrate the number of watts output at each wavelength across the entire spectrum of wavelengths, then superimpose that onto whatever sensitivity coefficient curve they wish to correlate to, and multiply..
The difference is analogous to Arnold & the Predator.. Predator was sensitive to infrared, not visible light.. The shift may not be as drastic with plants , but the concept is the same..

Plus Rep to ya!
Oh I understand you well enough, and agree with you on most parts. This is an interesting discourse. I don't get many opportunities like this. This is fun as well as educational.
I see your point about the sensitivity of plants to certain wavelengths over others. I agree. But the point I am trying to make is that bulbs are not capable of "selectively" reproducing light in different intensities. Taking your LED example a bit further, lets say we have a bulb that has an element designed to produce a spectrum of yellow/orange (570nm - 600nm) at 400w for flowering purposes. But we want to add an element to this bulb that will reproduce and add blue (450nm - 495nm) to the final light output. Our bulb now is producing light in 2 portions of the VISIBLE SPECTRUM with the same intensity, 400w. With nothing in between, above or below those wavelengths.
In nature, plants are subjected to all electromagnetic energy, both above and below the visible spectrum. So, yes, they get light beneficial for them that we cannot see. However, In an indoor environment, that plant gets only the light we give it with our bulb. Our bulb is emitting ONLY those frequencies it was designed to produce. There are no "invisible" portions for all intents, as there would be in natural sunlight.
Indoor grown plants are given light much like nutes. We give HPS (570-600nm) for flowering, and we give MH (450-475nm) for veg. If I understand you correctly, a conversion bulb is emitting light in both of these frequency ranges, PLUS light invisible to the eye, which to my knowledge is impossible. Our bulb can reproduce light ONLY in the ranges it's designed (and has elements) for. The light we see is the light the plants get. No more, no less. Even tho plants are more sensitive to certain light than others, we are still giving them light from the visible portion of the spectrum. Follow me?
What we need to establish is the frequency of non-visibile light plants are most able to make use of, and produce a bulb accordingly. But until then, they get what we give them. PAR doesn't come into the equation except to tell us which portions of the light WE GIVE THEM benefits them. Plants may well "see" the light we give them differently, but they are still seeing only the light we give them.
I know I took the round about way of explaining my theory, Sue me, I'm stoned!!!!

 

[born2killspam]

Oh, I get the confusion.. I think you're under the impression that mixed gas discharge spectra resemble a black body more than they really do.. Bulb spectrum graphs are kind of misleading this way because they integrate the output under a best fit line accurate to some mediocre resolution.. Infact the light in discharge lamps consists of bunches of very precise & unique wavelengths.. The spectral lines in the light depend on the arrangement of electrons in the element and the amounts of energy they need to jump between energy levels (and emit light of a particular frequency when they drop down a level).. In reality a bulb spectrum should look more like those terpine spectra that Greenhouse Seeds shows for their strains..
Bulb manufacturers just engineer the gas mixtures to have as many highly probable transitions within the desired spectrum range as well.. There are probably transitions outside the spectrum range that are unlisted but I don't know.. Also, the heated element enclosure would act as a true blackbody according to its 'true' temperature, but thats pretty negligable..
BTW, the sun isn't even a true black body, but its damn close.. Many atomic transitions occur.. There is quite a spike beyond the black body best fit curve in the blue region.. Also, there are cooler elements in the outer atmosphere that absorb certain wavelengths of radiation so there are dark lines in the spectrum as well.. It has the appearance of a blackbody at 5780K though, which is the same way bulbs are rated.. They don't have 'true' temperatures of their Kelvin ratings..
My point is, a localized spike or two can add up to a considerable amount of power because the entire output of the bulb is comprised of localized spikes.. The more spikes there are, the broader the spectrum, but a single spike can actually facilitate enough transitions to equal broad spectrum output in monochromatic light..

 

[Seamaiden]

No shit. I think I get that and, no shit! Really? So, what you're saying is that if the spike is big enough, it'll make up for (at least some) deficiencies?

 

[Seamaiden]

Oh, and a question regarding metal halides, at least as I've had experience with them... they're known to burn corals and other photosynthetic aquatics (miniature reef) that haven't been properly acclimated or just taken from under natural sunlight. If I recollect, metal halide (again, as I've experienced them) does emit UV radiation, which is one of the invisible wavelengths of light, is it not?

 

[born2killspam]

I know basically nothing about coral, but yes MH bulbs do emit quite a bit of UV light (Invisible light).. The bulb enclosure filters alot though, and more could be filtered further.. Standard glass filters the nasty UV-C and some UV-B pretty well by itself, but if nearer to visible wavelegths pose a problem then you could look into a special filter.. They make them for MH enclosures too since UV is harmful to ppl as well.. You might be able to get one at an electrical contracting outfitter in your town..

 

[Seamaiden]

I know basically nothing about coral, but yes MH bulbs do emit quite a bit of UV light (Invisible light).. The bulb enclosure filters alot though, and more could be filtered further.. Standard glass filters the nasty UV-C and some UV-B pretty well by itself, but if nearer to visible wavelegths pose a problem then you could look into a special filter.. They make them for MH enclosures too since UV is harmful to ppl as well.. You might be able to get one at an electrical contracting outfitter in your town..

My years growing corals and giant clams are long over. And yes, you are 100% correct about being able to filter through glass, this is commonly done in the miniature reefkeeping world.

But, I asked this because of lastpirate's statements regarding the MH bulbs and non-visible light. I thought to myself, "Surely, they produce UV light and that's a non-visible spectrum, right?" And the other reason why I asked is because I know that there are those who say that this exposure to UV radiation seems to be good for the plants as well.

Now, my previous question about your previous post and the spectral spikes, did I understand you correctly? That if there is/are (a) large enough spike(s) in certain parts of the spectrum that it makes up for lack of peak in other spectra?

Oh, do HPS produce any non-visible wavelengths? Guess I could Google, huh?

 

[born2killspam]

I think it would be better to say that large enough spikes at specific wavelengths will suffice to make up for the lack of adjacent wavelengths (eg if we have transitions resulting in say 472.1nm output, then we don't need anything else in the gas mixture that produces radiation at 470-475nm, without deviating too much from an ideal spectrum.. Thats really as good as we can do with HID, we obviously can't create a mixture with as many possible transitions that occur in the sun..
On the otherhand though, plants do drow under LED, which is monochromatic (one infinitesimally narrow spike), and decent results can be gotten using enough watts of MH in flowering, but most ppl would agree that its best to use a spectrum that most mimicks the sun at any given time in the season.. I imagine we'll start to learn more about the complexities involved here now that its becoming more feasible to experiment with large wattages of LED, and other specialized spectrums..