Results CFL vs T5 vs HPS in ScroG

After doing a bit of research, it seems that with HPS wattages below 250hps the difference in yield between CFL/T5 is not all that much different.

*Note...this is for Scrog Only where the penetration depth isn't as big of an issue when compared to untrained or Sog style grows*

It seems to be more of a difference in compactness but not total yield. This is NOT from my experiment, but comes from researching and comparing Scrog yields between 250(cool tube & air cooled) watt hps and cfl setups with [6 - 8]42watt cfls and 2ft 8 bulb HO systems.

Keep in mind I have an HPS/T5/ and CFL and have no particular bias towards any.

From those aforementioned systems after normalizing, the average yield in scrog came to about 4.5-5 oz.

• Number of plants averaged 2. The addition of an extra plant had no significant effect on yield.
• Veg time was approx. 4 weeks
• Flower time approx 54 days give or take a few
• Screen Size 1ftX3ft and some were 2ftX2ft
• Lumen comparison 250 hps = approx 28,500; Lumen T5 8 bulb = approx 16,000;Lumen 6-8 42watt cfl = 16,200 - 21,600;

I was surprised because at this particular wattage, there was no clear winner. (The point of light was always above the canopy. No side lighting)

The total system wattage used was about even. With the 250hps system you need a bit more elegant venting with inline fans(cool tube). So extra fan watts go to that. However, this seems to even out in that you need more CFL's/T5 wattage to equal an HPS lumen output.

Growers reported no difference in bud potency. Perhaps compact buds look better...but appears to be no difference in the bowl. Most used hydro, typically DWC. A few soil grows were in there, and the yield was slightly less.


Other Observations:

Use of Approx. half of the wattage yielded roughly half of the results. One scrogger used a 2ft 4 bulb T5 and yielded approx 2.2 ounces. When increasing the wattage, the HPS scales far better.

Conclusion:

In a Scrog, the yields between those lighting systems were roughly the same.

Yields in a free grow (ie no training) the HPS performed significantly better.

Grows over 250watts the HPS performed significantly better Scrog or otherwise. A 600watt hps Scrog could yield close to a pound.


While I can provide links to all the grows there is no point. I will say that there is website with a forum dedicated specifically to 250watt hps grows. Take what you find is useful...or try it out for yourself

Mods feel free to move this post to whichever sub-forum you see fit.

I hope this info is useful to some out there.

nice thread man.
cant believe no one posted on it.
thanks for the info. but in your info i wasnt clear on how many 42 watt CFL's= 1 250w HPS.
so what is it?

pce

BTW lumens don't add, so you take whatever cfl has the highest lumen output and that's the highest that's being put out. If they're all say 2,700 lumens then the plant is recieving in theory 2,700 lumen more spread over the plant intensely.

ghengiskhan said:

BTW lumens don't add, so you take whatever cfl has the highest lumen output and that's the highest that's being put out. If they're all say 2,700 lumens then the plant is recieving in theory 2,700 lumen more spread over the plant intensely.

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That means that an 8 bulb h.o. t5 only puts out 5000 lumens spread over 8 bulbs. Right? because each bulb by itself only produces 5000 lumens so placing 8 together doesnt make the lumen output 40,000 just 5000 spread pver 8 bulbs?

I saw pics on here in someones grow journal of a light meter next to one cfl and then another pic with the meter next to 2 cfl's, the difference was only 1 lumen with the extra bulb.

Ive been curious about T5s for a scrog, im about to start a 400 hps scrog, but the idea of the low heat of T5s is so appealing to me. I was wondering about a 4ft 8bulb Ts, it puts out 40k lumens, my hps puts out 55k but that dramatically decreases from the distance you have to keep it. I dont think the watts are much more either. Anybody got any input on this?

4. What does this mean when using multiple light sources?

So we've established that lux are the number of photons striking a unit area per unit time, weighted by a luminosity function.

We've also established that photons from the same light source are indistinguishable, as long as they have the same energy/wavelength/color.

What this means is that if you put two lights the same distance from a point, and each light provides N photons per unit area at the point, with two lights you will have 2N photons per unit area at the point. Because intensity is a measure of the number of photons per unit area, the light is twice as intense, whatever unit you choose to use. Twice the lumens, twice the lux, twice the footcandles.

An obvious practical caveat to this point comes when using multiple low-intensity light sources. Notice how I stated that the lights were at the same distance? A practical problem with CFLs, for example, is that while you can get 27000 lumens from 10 x 42W CFLs, it's difficult to get them close enough to make them useful. If you have them in a line, for example, as I've shown below, each successive light is further from the meter, and the effective increase will be reduced. They still add, but according to the 1/d^2 rule, so having a bulb 2cm farther away will yield diminishing returns. On the other hand, this can be an effective way of distributing light, whereas with HID you need to distribute the plants around your single point light source.

5. Seriously? Prove it.

Here is a simple experiment that demonstrates this point. Below are some 42W bulbs that are a part of a flowering cabinet. I have suspended it from some pots for the sake of this experiment. You can see there is also a 150W HPS in there; I'll do some HID vs. CFL comparisons at some point as well.

The point is simple. Lights that are equidistant from a point contribute additively.

Ambient light = 0



1 x 42W = 6500 ftc ~ 65000 lux



2 x 42W = 13100 ftc ~ 131000 lux



Any questions?

More examples and experiments to come.

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Forgive me if i'm wrong... but why does the sticky at the top say that LUMENS DO add?

Just don't get it.

Also why does everyone advertise lumens in the thousands when only using a (fort example) 8bulb T5 fixture. They advertise that it's a 40,000 lumen fixture.. when in realality it's only a 5,000 lumen fixture with better spread...?

This just is'nt adding up, please explain a little more..

Thk.

hmm thats cool.. so more lights = more lumens?

almost i year old nice.

ah.. new to me

MediMary said:

ah.. new to me

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its cool man , yes more lights = more lumens(or lux actually)

MediMary said:

ah.. new to me

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nice job doing your research! i would much rather see a 1year old post come up than a 100 of the same question come up! Rep + for researching


Peace

thanks sir, I try and search for the info I need before posting up in the threads, Sometimes a little confusing when you find lots of different people with lots of different views, for the longest time I had been under the assumption that more lights, dont add more lux...

MediMary said:

thanks sir, I try and search for the info I need before posting up in the threads, Sometimes a little confusing when you find lots of different people with lots of different views, for the longest time I had been under the assumption that more lights, dont add more lux...

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the biggest debates are the hardest to understand. Just take it all in and apply some common sense and should be good to go. my head spins out of control when this debate comes up...BUT i am lazy and dont like to read on what is actually true as it bores me! lol


Peace

I don't care if this is old it deserves to be read

Up you go!