Lighting an orchid closet - fluorescent or LED? Otherwise?

[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.

[fishmommy]

The Jungle Dawn 13w LED bulb I measured today gave 1500 fc at 1 foot distance straight under the bulb.
A foot to either side gave much less, more like 500.
FYI .
I am using it to light a 10inch x 10inch x 20inch tall terrarium for low light plants.

[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.

[Ray]

Originally Posted by fishmommy

The Jungle Dawn 13w LED bulb I measured today gave 1500 fc at 1 foot distance straight under the bulb.
A foot to either side gave much less, more like 500.
FYI .
I am using it to light a 10inch x 10inch x 20inch tall terrarium for low light plants.

May I ask about your measuring device?

I tested mine with a Hydrofarm light meter, and saw about 800-900 fc 12 " below and ~400 a foot to the side.

[fishmommy]

Originally Posted by Ray

May I ask about your measuring device?

I tested mine with a Hydrofarm light meter, and saw about 800-900 fc 12 " below and ~400 a foot to the side.

It's just a regular old Hydrofarm light meter. I used a ruler and everything Could my reflector make the difference?
Also, this bulb is not available yet separately. It is 12W (I thought it was the 13 but nope) I bought these for my terrariums, which are 10g tanks stood on end:
Exo Terra Compact Top Nano 8" WITH LED Light Included

[Ray]

Certainly. From what I can see, the Jungle Dawn horizontal light has no lenses on the LEDs, so light can spread pretty widely.

[littlefrog]

The jungle dawns are designed to light up a terrarium (fish tank) style area, which is reasonably narrow but deep. I've been recommending one for a 12x12x18 or similar size. Two for a 24x18x18 tank. All I can say is that nobody goes back to CFLs once they've tried them (unless they need heat, and some people do). People are reporting good color on bromeliads, and great plant growth. A few people say they've sunburned plants with them, I have a bit of doubt on that, but they are bright...

They are rated at 13W, which is a little deceptive. The chips total 13W, but the actual power draw is on the order of 10W using my meter. This is typical for this style of light, something to do with the way the internal ballasts work.

I'm not a lighting engineer or a physicist (my PhD is in molecular biology). So I'm not going to debate photons and lux and the like. All I know is that in real life they work fine. I wouldn't have spent a gazillion dollars converting my growing area to LEDs if it didn't work, believe me. I sell plants for (part of) a living, I'm not going to invest in something just for giggles. I encourage you to try one if you are sceptical, that is the only way to see. If they don't work for you, then you know for sure. I haven't had any complaints. It does bother me somewhat that there are people who insist they don't work because of (... fill in the blank...). They are the same people that said fluorescents didn't work, I think. You won't know unless you try. I'll be happy to take back any of mine that you are unhappy with.

Right now I have a few discontinued white LEDs (12W) that I'm selling at a pretty good discount just to make space. They don't have quite the same color light as the new ones, but it is a good way to play with LEDs for a bit less, they are a high quality light, just an old model. They are $23.99. 'Regular' 13W lights are $36.99 (or 3/$100). There are also 'spotlight' styles available in 24 or 36W, and even some with added red and blue chips to enhance the plant spectrum. If you want UV, I can do that too (but not all those things in one bulb, yet).

I also have some wickedly awesome LED 'striplights' - they look kind of like a t-5 tube but not quite. Same dimensions. I'd say somewhere between a t-8 and a t-5 in real light output. A whole lotta chips in a linear configuration, the whole thing encased in acrylic so it is effectively waterproof. I like to whack them on a table when demonstrating them, try that with a fluorescent! I haven't had time to list them, but if you are interested, drop me a line. I have those in red, white, and blue, very patriotic.

PM me and I'll answer any questions you have (that I can answer).

Rob