Lighting an orchid closet - fluorescent or LED? Otherwise?

[DavidCampen]

Originally Posted by Magnus A

I am now testing a LED panel with white light that gives 110 lm/W. As T5 fluorescent with good spectra give about 75-80 lm/W (OSRAM DULUX® L LUMILUX®) the difference is significant.

LED technology moves FAST!

We are talking about lights for plant growth not human vision. Lumens is a fairly useless metric for evaluating lights for plant growth. The lumen metric is strongly weighted to human vision. You could have an LED emitting 200 lumens per watt of 555 nm light and it would be less efficacious for plant growth than an LED giving 20 lumen per watt at 660 nm.

[Magnus A]

Originally Posted by DavidCampen

We are talking about lights for plant growth not human vision. Lumens is a fairly useless metric for evaluating lights for plant growth. The lumen metric is strongly weighted to human vision. You could have an LED emitting 200 lumens per watt of 555 nm light and it would be less efficacious for plant growth than an LED giving 20 lumen per watt at 660 nm.

You are speculating and fabricate false data about the LED panel I have!

And you are wrong as the lumen measurement is NOT weighted! It is a photon count independent from wavelenght of the individual photon.

The wavelenght spectra of the LED panel I have is low at 500 and have maximum at 440 an 600. It IS though lower in blue than red, but strong enough to trigger antocyanin production ( Sophronitis and rupicolous Laelia) for protection from high energy photons (blue light)


LED IS the future for light and the first real system that is useful has come out on the market.

[DavidCampen]

Originally Posted by Magnus A

You are speculating and fabricate false data about the LED panel I have!

Please tell me explicitly what you think it is that I have fabricated. I stand by my statements as accurate and correct.

And you are wrong as the lumen measurement is NOT weighted! It is a photon count independent from wavelenght of the individual photon.

Sorry but you are very wrong. The lumen metric is _not_ a "photon count independent from wavelength" This is very basic, you should know this if you want to comment on plant growth light systems.

[Magnus A]

Originally Posted by DavidCampen

Please tell me explicitly what you think it is that I have fabricated. I stand by my statements as accurate and correct.

You wrote:
"You could have an LED emitting 200 lumens per watt of 555 nm light and it would be less efficacious for plant growth than an LED giving 20 lumen per watt at 660 nm."

As my LED panel is totaly different than that you are fabricating the specification!

Originally Posted by DavidCampen

Sorry but you are very wrong. The lumen metric is _not_ a "photon count independent from wavelength" This is very basic, you should know this if you want to comment on plant growth light systems.

Sorry, I was to fast.

So if lumen is useless HOW should be compare different light source?

[DavidCampen]

Originally Posted by Magnus A

You wrote:
"You could have an LED emitting 200 lumens per watt of 555 nm light and it would be less efficacious for plant growth than an LED giving 20 lumen per watt at 660 nm."

As my LED panel is totaly different than that you are fabricating the specification!

I was discussing a hypothetical, not the specifications of the LED panel that you mentioned.

Sorry, I was to fast.

So if lumen is useless HOW should be compare different light source?

A light meter that measures lux or footcandles is the best that a hobby user can afford and for monochromatic light the lux or fc values can be precisely converted to micromoles/watt-second. To have the best information possible for a polychromatic light you would need micromoles/watt-second measured at a number of wavelengths.

[Paddle_grl]

I don't have a closet, however, I do have a 5' x 4' curio cabinet. The short and squaty kind with a rounded front. I have it set up with 2 17 watt T-8 {the single fixtures with balast and it's own cord} 2, to a shelf. One cool white, and one soft white. I got mine for $10.00 a fixture at a local grocery store. I have 3 shelves. I have neumerous suculents, jade plant, cacti, and a few misc. others. They are on the top shelf, inches away from the light. They do ok, kind of tend to stretch out as they would love lots more light. That's why they are currently enjoying the MI summer outside. I have a few Phal's, and they loved it! Along with an african violet. All together with 6 single fixtures, it uses 120 watts for 12-14 hours a day. Pretty inexpensive. You could do something similar in your closet with a double utility fixture per shelf.
** Oh, and I do not have a fan in the cabinet. With the door closed, it maintains 82 degrees or so. At night, I crack open the door wide enough for a temp change, but not wide enough to let the cats nibble on the leaves.
My requirement were a little different. I wanted natural light as the curio cabinet doubled as a showcase and growing cabinet. LED lights are just still too expensive, and again, I wanted natural light.
If you do a mixed bag of flowers such as high light and low light plants, you could put the high lights on the top, and use the filtered light for the orchids....or put the low's on top and have an extra light for the high lights. Just my 2 cents.