Mount cfl horrizontly

It can be effective either way, just try to get a reflector in each case if room provides. Any way you can stick em in close to the plants will work, whether vertical, horizontal or skewed any which way. Whatever is best for your grow room.

 

This isn't actually correct. CFLs don't emit light in the same way as other types of bulbs. The highest output of light comes from the sides. Ideally you absolutely want to mount CFLs horizontally.

 

Not to down your post or anything, I've seen plenty of others post too, but this kind of sounds like an urban myth thing.

Out of personal experience, I have no problems running them vertically. Also, the CFL is made from a round tube. It'd be similar to saying that a florescent tube light only emits light from one side.

You know what I'm saying?

 

This is not actually an urban myth. I'm not saying that you can't get great results mounting vertically with a reflector. However, the lumen output on the sides will be greater than the top. In an incandescent bulb, the filament is heated and produces the greatest amount of lumens out of the top. However, in CFLs, argon/mercury is heated to produce the light. The argon/mercury at the top of the CFL will be the coolest as it is the farthest from the heat source, which is at the base. Besides this, the sides will have a greater surface area, thus producing more lumens.

 

This is a valid point.

I still have a feeling that any stress you put yourself through to mount CFLs sideways wouldn't be worth it.

I personally don't exactly see a difference between looking at the front of the bulb or the side. I don't see that in incandescent bulbs either to be honest. The incandescent bulb heats a filament, which would put off light in all directions.

Fluorescents don't work by heat though. The reason the ends are hotter is due to the fact that the electrodes are located in the end caps. These are what transfer the power to the intert gas inside the tube.

I did a short search on Google, and came up with no credible results on where a florescent is the brightest. The only one I came up with, which has ZERO credibility, actually says florescent tubes are brightest in the center. If this were true, which I highly doubt, that'd make the end the brightest. Unfortunately, it has zero reliability, so we shall disregard that.

This is where I stand. If the sides were brighter, we could easily tell by positioning a light in front of our eyes and seeing the brightness difference. You can go try it, but I highly doubt you'll notice a difference. Even if there WAS a difference, that you couldn't notice, the effects on your plant would more than likely be negligible. When I look into a t5 bulb, or similar, I can't exactly tell where it's the brightest. It's pretty even visually.

My conclusion? Mount them however you can. Short of mounting them with the tube pointing away from your plants, you should be fine mounting them any way you can! I'll dig for some information, but I doubt there will be any.

I don't want to be hostile, I would just enjoy some educational conversations!

 

No, no, not taking it hostile at all. I like the dialogue!

I don't think that you can take the approach of looking at the bulb to measure the intensity though (for growing purposes that is). My argument would be, if you put your eyes 1/4 inch from the CFL it would be bright, if you move back 4 inches away, probably looks just as bright. But in reality, luminous intensity would be far greater 1/4 inch away than 4 inches away. So while it looks just as bright, it's not actually when measuring in scientific units. Not only this, but our eyes don't pick up all wavelengths emitted, so you don't see some of that intensity. You really need a light meter that measures luminance to be able to determine the difference from the top to the sides.

In the end though, whatever works for you.

 

Well... your eye can tell differences between intensuty of light. Grab a 13 watt and a 27 watt and put them side by side.

We need someone that has a way to measure luminosity!

 

True, only visible wavelengths though. You can get lux meters pretty cheap online, someone should get one!