Hi! I'm about to try LED. Thinking of 10pcs 9W (1W red luminance:30LM,1W blue:15LM). As for the wave length of blue:min:460--max475; Red:min620--max:640. Does it look ok?

If we assume LEDs are as effective as fluorescent, you need at least 50 and preferable 100 watts PSF - check out Blab's 80 watt PSF CFL grow.

So, assuming 80 watts PSF, your 9 watts are good for 4 inches by 4 inches by 12 inches.

Sorry I ment a total of 90W. but is luminance and wave length ok?

How did you choose your leds what specs should I look for I don´t know a lot about leds can you help?

Ideal plant spectrum is 665 nm for red and 430 nm for blue. High power LED's r Best.

90 watts of led should be ample to grow under in my humble opinion but only from what ive read.
the red and blue spectrums are a debatable point apparently as many people seem to think that plants prefer a broader spectrum but i think its well worth trying especially since there seems to be few cannabis grows using them and i would like to see what can be achieved with these lights.