Lumen Equality?

Yes and no. Lumens actually is a rating of the bulb's light output at a fixed distance, so in an "all other things being equal" test 50k lumens is 50k lumens. But, if you have two different bulbs of the same lumens but one is closer to the plant than the other, then the closer one will be delivering more true light intensity. Lumens also doesn't account for which spectrum of light is being delivered.

 

You would have to. While they add up to the same total lumens, each bulb can only achieve the penetration of its stand-alone lower lumen output. So with CFLs, lots of them surrounding the plant very close will work quite well. But there also comes a point where you would have been better off with a single HID rather than a forest of CFLs.

 

All lights are not the same when it comes to PAR. We require new thinking about the way we measure light for use by plants. The typical rating most growers are familiar with is the “lumen.” The definition of the lumen is the total light produced within the range of the human visual response. It tells us nothing about the distribution of that light energy over the spectrum, and most importantly, it doesn’t tell us how much is useful for plants.
The problem with lumens is especially pronounced when measuring light at the far ends of the human visual response curve. Consider three lamps—red, green and blue—each emitting the same number of watts of optical energy. The red and blue lamps would have much lower lumen ratings compared to the green lamp, simply because the human visual response is very low at red and blue, and highest at green. That’s why a high lumen rating does not necessarily make a lamp better suited to growing plants.

 

This is true (except that lights don't emit "watts of optical energy", a watt is a unit of electrical consumption, but point taken). A bulb with a bazillion lumens but all in a part of the frequency that the plants can't use is no good to them. That's why growers first should look to the spectrum. But much of that has already been narrowed down, growers know which kinds of bulbs to look at and which ones not to in the first place.

 

Great information!!!! I could read stuff like this for hours. I am also a professional photographer so I value light as my most priced asset. Been researching lumes for a while now and I have to say I agree with the fact that plants really don't give a shit. If your other variables are correct, that will increase your production, i.e. soil, proper water and watering tecniques, constant correctly spectrummed light and light tempature, heat index.... not lumens. Almost an invaluable refference IMO. Mine are 1400 lumens, 100w, 5500k and I don't see a problem with using and recommending them. Again Great Information!!! Please inform me privately if you have any additional info you might want to share.

....now sir please excuse me while I climb under my desk. I am sure my boldness will stir up a shit storms the likes of no other.

 

If those are the lumens then the bulbs you have are marketed as 100 "equivalent" watts, but they aren't 100 actual watts they are more like 23-27 actual watts. CFLs are sold as replacements for household incandescent bulbs, and since those had been the standard for decades people came to understand a bulb of a certain wattage equaling a certain amount of light. So to market CFLs, which use much less energy than incandescents to produce the same amount of light, they say that the bulb has "equivalent" watts. It's really a shorthand way for them to say "this CFL bulb, which consumes 23 actual watts, has roughly the same lumens as a 100w incandescent bulb." Those "equivalent" watts make some sense when marketing as household replacement bulbs, but the "equivalent" means absolutely nothing when it comes to growing MJ, look only at actual watts.

 

Yes that is correct. On the box is says 23=100 watts.