Light intensity?

Does equal wattage of flouros give as much light intensity as a MH or HPS?

For instance, is a 100w flouro equal to a 100w MH in the vegging stage?

Could you replace one with the other without affecting crops?

nope, you should at least look at the lumens output for a basic idea of intensity.

HPS and MH make around twice the amount of light that floros' can..

Theres a bunch of good info on that stuff in the FAQs.

One thing is light output intensity and another light flux density.

Puntual bulbs, as HPS and MH give very far more intensity the fluoros, wich produces a more evenly light distribution. Intensity refers to how far the light reaches with efficacy. HPS and MH allows to grow taller plants.

The flux density depends of how the light are distributed and the bulbs efficiency. Currently, 4ft fluoros with electronic ballast (wich are cheap and reliable, dont as electronic ballast for HID) have similar efficiency than 400w HPS (and better than MH), and produce a enenly light distribution, wich do them very appropiate for SCROG grow. But 600w and higher HPS are more efficients than fluoros.

Its easy to confuse ad hype with facts, expecially with all the snake oil flying around in the hydroponics market.

Anyone else watch the Penn and Teller Bullshit! episode on showtime last week about numbers?? You have to be careful on this stuff and realize that just about everyone with a buisness permit wants to make you buy their products and they can cook up numbers likewise.

Flouro pushers like to compair "over the life of the bulb" and "mean lumens" to compair ever so wrongly thier products to HID. Its no secret that HID bulbs only last an effective 5000-8000 hrs or so before they should be replaced. Florecent bulbs continue to put out decent light for almost 20k hours. See the graph posted below.

Here is the manufacturers actual data comparison:

-Metal Hallide:
Mean Lumens: 23,500
Relative Mean Light Output: 100%
Mean lm/W : 51

-4 Lamp T5 HO setup
Mean Lumens: 28,400
Relative Mean Light Output: 121%
Mean lm/W : 77

WOW! What great numbers for flouros??? I thought it couldnt be possible!! NOT...

The trick is to look at the way they spin this. They calculate averages over 20k hours for all bulbs, even though HPS and MH would NEVER be used that long. Take a look at the graph and see what you would rather spend $.10 per kw/hr generating for the next 8000 hours or so.

Flourecent lights have come a LONG way in the last decade but not that far.. nor will they probably ever. If you want an alternate lighting solution try LED's. They are pricy right now but the cost in electricity savings and their 50k hr lifespan will bring them down in price in the next couple of years. They also only generate specific light colors and can be set directly to the cloroplast reactive spectrums with little to no light outside of which. I am using a 7,500k 60 LED bulb in an experiment to feminize plants. We will see what happens.

Thanks guys for the reply to my question.

Yeah Aaron385 I studied your graph and undertsand how it is "spun" and a pretty good spin at that.

Also, your point is valid in that it is ALL about the lumens!

My buddies are just cramped for space and need supplemental lighting in addition to the 400 & 600 MH & HPSs they are currently running.

You know... flouros hung in the corner of a closet over small mothers or clones.

When i said that 4ft fluoros (triphosphor T8 with electronic ballast) are of similar efficiency than a 400w HPS, i refer to initial output.

I put the output of Phillips SON T-Green Power (one of the best HPS in the market) and of the Phillips fluoros 830. You can see that the photosyntetic efficiency (PUR) per watt are very similar, as well as system efficiency.

And yes, leds are the future, but currently, its efficiency is below HPS. But using only reds and blue, it can be compensated by its better spectum to promote photosyntesis. Use white led dont make sense. You lost the spectrum advantage, have very poor efficiency and last less than 10000h (in fact, if you dont run them properly, they burn out in 3-6000h).

I cant really analize these charts for a couple of reasons, one I am unfamilliar with the method used to determine "photosyntetic efficiency (PUR)" or what sampling criteria was used to determine this. Two: it is hard for me to analize this because I have no idea where the numbers came from. I have worked in the engineering field for 7 years now and I see weird charts like this all the time and if I cant get the sampling criteria and test methods defined readily I have found results to be inconclusive.

I still see lm/w is much higher on HPS

Anyone with expierence growing under both?? I always see floros with good numbers but anyone that uses them switches back to HID (thats just what I keep running into). Is there anyone out there who E-bayed their HID's when they got a hold of some triphosphor T8s with electronic ballasts?

Its probably somewhat accurate, you sound like a smart guy and all. In fact, what do you think of digital ballasts compaired to normal ones for HPS and is their a hands down winner out there as far as brand names go or are they all pretty close like the non-digital ballasts?

If you get a chance, please check out my thread in this section about CO2 if you could.

To clarify on the LEDs, I read on a gardening site a study that concluded that that spectrum of light was barely present in natural light but when certain plants were exposed to it they became mostly female. I figured what can it hurt? The 2 watts the bulb uses isnt going to even show up on my bill.. haha

Glad to meet someone who can understand what i want to mean. The data are computed by me, from the specs of reputable and reliable manufacturers.

A made a sheet table wich compute emission in micromols of phothons given the SPD (spectral power distribution) and lm output. This is the PPF (or PAR) data wich some agro bulbs manufactures provides, and the error margin are often below 5%.

Then, correct it by cannabis quantum yield (capacity of produce O2 from light imput). To build it, i use the photosyntetic action curve from Inada (1972), very similar to the McCree curve, and obtained like an average of 26 plants herb species. Its proved that differences with other species are little. And correct it for the cannabis spectrum absorbance (obtained from Us gov archives about MJ fields in Colombia: strain Colombian Sativa at Jul25). From that data, i obtained the PUR data. You can see details and dowload it here .

About HPS digital ballast, there are too much marketing claims. They dont increase output, but reduce power lamp mataining aprox the same ouptup and the ballast itselves lose less watts the magnetic ones. The best about HID digital ballast is they made the HPS bulbs last longer (and from that, with acrobatic maths, manufactures obtain their fantastic claims). Their problem, price, although is dropping fast, and reliability at high wattages (600w and higher).

In the other hand, fluoros digital ballast are cheap and reliable. Actually, any informed person who want to use fluoros might use them.

Im very interested on led growing, there are a thread open in http://boards.cannabis.com/showthrea...t=34819&page=7. I think its the right thread to continue talking about

Oh, i see you grow all type of vegetables hidroponically. I want to perform so LEds experiments with differents plants species (so im developing leds luminaries targeting compete with HID lamps in comercial vegetables grow). I think we can colaborate in the future.

You could say I am using innocent hardware store plants to test my theories and gain the skill I will need when I move on to bigger and better things.

So I can see from your other posts that you have figured out the limits of the knoledge base of this hobby/sport/buisness as well. I looked over all of your data and I believe I can really now endorse some of your findings in the ability of some of these new fluorescents to hit the right light spectrum with more energy proportionally than HID. I have questioned the broad spectrum of the HID lights before. Now I am really curious about single spectrum LEDâ??s. I checked out the LED topic and posted there too.

Ok so roughly LEDâ??s are up to incandescent output levels in lumens per size bulb but I am curious what kind of rating in your system they would receive if they used the proper semi-conductor to generate only photons in the peak photosynthetic spectrums. Ultimately, what amount of light would be required and if LEDs could really be as good as they say? I can tell that the â??grow LEDsâ?� that are on eBay now are just something put together from stock LEDs that are somewhere close to the right spectrum but not ever initially engineered for this use. There could be a big future there.

Thanks for the info on electric ballasts. I caught their crafty math already on them for sure and my industrial experience with their big brothers generally involved them catching on fire quite often. Not the roaring blaze type of fire, just the melting white smoke of electronics burning followed by a big BOOM and then circuit breakers tripping. I am sure the technology will be there soon but I think I am going to take advantage of the $50 core and coil ballast kits they have all but made â??obsoleteâ?� in the market hype that IS hydroponics.

I am planning on fluorescent light augmentation on my grow room. I will check out the digital ballasts for them.

I am more than willing to collaborate on anything in this field. I have seen many different arenas that good science and engineering could affect but none as prime as this field. The entire range of hydroponics could benefit from careful application of some new emerging technologies like LED grow lights and the increasingly prevalent augmentations to standard fluorescent bulb inner coatings.