The best ScroG LED lights are the ones you build yourself.
The commercial lamps follow the HID form factor. All that light packed in a smaller area. You want to spread the LEDs out at 1.5 to 2" spacings and use wider angles with lower wattage to keep the light low.
Here is my 1st LED test grow in a PC case I threw together. Notice how I'm using all of the footprint of the room for my light array? This leads to more efficient use of the light.
LED can be done, do your research and don't shoot for the moon your first time. Do not grow like you would with HID either, the plants grow differently under LED, seems they really eat up the Mg.
I have 40 Watts per square foot in this case with a 21 Watt array running. If I get over 21 grams that is over 1 gram per watt. Sounds good to me. I'm still nervous these LEDs won't pack on the weight, but I hope they add enough for me to be pleased with. I intend to go LED in my 3'x2' cab.
These are day 21 of flower. Now they are on day 27 with buds that are doubled in size and looking more resinous as the days pass. Seems like LED is on track with HID so far. Micro grows utilizing LED is the way to go right now. Heat is almost nil and the LED light really does well in small confined spaces like this.
If you want trees, you need 3W-5W emitters with lenses most likely. LEDs are meant for small short plants. The highly efficient 1W emitters are good at short SoG or ScroG setups. Commercial lamps usually use inefficient 3W and 5W emitters which throw off more heat than light, although the light output is a bit more than with the 1W emitters. LED is a technology that needs to be understood before you attempt to make a grow light.
One word of advice from me is stay away from UFO style lights. These are mass produced in China with the same crappy LEDs, just in different LED color configs and new company labels printed on the metal housing. Stick to efficient name brand high power emitters with known efficiency and data sheets.
Edited by TBM, 12 March 2011 - 04:08 PM.