LED Lights

[Tele fan]

I made a nice wooden fixture to mount the track on.
Ugly is a matter of perspective. As soon as I figure out how to post some photos I will put one on that shows the fixture. My plants are doing well under those lights.

[swords]

Tele Fan I'd LOVE to see pics of your LED setup.
It would gimmie some idea what to do with mine!

[Tele fan]

I take some pictures this week. Still trying to figure out how to post pics.

[swords]

You must have a website, or free online photo hosting service (like Photobucket.com), upload your images to your site/account and then click post reply on the forums. Above the Message box there's a yellow square with a mountain and sun (it will say Insert Image if you let your cursor rest on it). Click this square and type in the URL (website address) where you uploaded your images. hit submit reply and that's it!

edit: I now see that you can add an image in the quick reply at the bottom of the post's page, that's handy! More forums need that feature!

[quiltergal]

Actually you can upload photos directly from your PC. Just above the reply textbox in the tool bar click on the paperclip (next to the smilie). Click browse in the dialog box and go to My Documents or My Pictures or where ever on your PC that you store your pictures. Click on the one you want. Click open and then upload. The picture will be included when you click submit. Wah lah! Piece of cake.

It is a really nice feature isn't it Swords? Thanks Marty!

[Tele fan]

Thanks for the tip. How does one remove photos from the gallery that are not wanted?

[Ocelaris]

This may be beating a dead horse... but LEDs are about the worse source of light for plants you can get.

1) They are NOT efficient, they only manage 40-50 lumens per watt. Florescents and HIDS are in the 80-120 range.

2) LEDs do not put out light in the chlorophyll absorpbtion bands... i.e. the light LEDs put out are very narrow banded and useless to plants. White LEDs are also fairly useless because the blue is too high in the spectrum, and they fade out before reaching the red spectrum chlorophyll requires.

Here we see a graph produced by National Semiconductor guest speaker from Future LEDs, with Philips Lumileds representative, and a nat semi engineer all in concurrence.

The top part is the absorption bands of chlorophyll, black is where the light NEEDs to be to be useful to plants. You can correlate that to the color chart below.
The second section is the emission spectrum of Blue 470nm, green 525nm, and red 630nm LEDs... You can see clearly that all of the light output of LEDs falls TOTALLY outside the range of chlorophyll absorption.
Next section is the color chart, fairly self explanatory.
The bottom section is our color receptors each respectively, Blue, Green, and Red which over lap... LEDs are useful for human vision, but their narrow peaks make them useless for the purpose of growing plants.

If you want to see the entire presentation, please go here (you must register, but don't worry they're good about not giving out addresses):
Analog By Design Show 6



LEDs are wonderful for lots of things... Plants are not one of them.

[Ross]

While I have not always been a supporter of posts regarding LEDs, I wholeheartedly support this post. If you want light, get light! You get what you pay for.

[Ocelaris]

Here's a typical 4000k Metal halide spectrum chart for reference... (CF/T5 etc... are very similar)



And the average Chlorophyll absoption spectra... human vision is the opposite... pic by Ivo Busko

[maldorer]

I have just started with some orchids under LEDs. I have 320 LEDs (8:1 red:blue) that pull 30 watts. I power them with a 12V battery that charges during the day via a 75W solar panel. At ~2.5amps/hour I use about half of my 35 aH battery capacity in 6 or so hours (sunset to sunset + 6hrs.). Then it's lights out until I collect some more sun juice! I'll let you know how I fair.