Lumen output for warm-light fluorescents

[Ben Brewcat]

I'm building a lighted stand for my Nepenthes and my soon-to-land orchid hobby ('cuz I TOTALLY need another hobby). In researching lighting, I've noted that the lumen output for the warmer-spectrum fluorescent bulbs, lower K-values, have significantly diminished lumen output per bulb. For example a 4' T5 in "cool white" has about 5000 lumens. The same bulb in "natural" or "warm white" pushes about 2600! I like to incorporate some warm lamps for visual effect, but my previous setups were regular ole T5 or T8s and my plants then didn't really need the HO lighting.

Now these are bulbs at BLowes and Home Despot. I haven't tried the Trustafarians at the grow store yet... while sometimes they're very well-informed, sometimes they aren't. At the top of their voice. And if you're growing something legal, I find they are even less well-informed .

BUT: is this universal for fluoros, just a trade-off for the change in spectrum? And for the nerd in me, anyone know why if that is the case?

[Gypsi]

I've had problems getting the correct light spectrum for freshwater aquarium lighting in the newer bulbs. Aquarium plants like a lot of red and blue in the spectrum output, yellows/greens promote competitive algae growth.
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I don't know where to get this spectrum in a T-5, but can still get a close bulb in T-8's. (and do not expect Bulbs.com to be able to comprehend plant spectrums. Been there, tried that.)

Gypsi

[johns bees]

hi I used to work for a lighting company. What you are looking for is the full spectrum t5 or t8 they run about 12 bucks each for the t8
they give off 6500 K or lumens they will work well for plants. you can also use a cool white and a warm white t8 lamps in the same fixrure
to get lighting that plants grow in. Good Luck with the orchids.

[Ben Brewcat]

K and lumens are completely different... one is spectrum and the other output right?

[Swobee]

K and lumens are completely different... one is spectrum and the other output right?

Correct, they are completely different - the 3500K or 5000K or whatever is the color 'temperature' or light spectrum while lumens is a measure of light intensity or 'volume' or 'output' to put it another way. More lumens, brighter, less lumens romantic? or at least dimmer. We are using mostly 3500K and a few 5000K spectrum CFL's in our home for example. The light is more natural to my eyes at 3500K. The stypical 2600K soft white was too yellowing a light for my tastes in some of our lamps and fixtures.