I was recently thinking, could LED's be useful for growing? They can be extremly birght and are very very light on power use... Grow lights of the future? But there must be a reason they are not used because otherwise im sure somone would have thought of it by now.
There are some pretty extensive threads on this topic recently, try searching and see if you find them. The short answer is yes they can be used and there are some LED grow lighting set-ups becoming available.
They aren't used much right now, because the cost to set up an efficient grow with them would be very high, but in about 5 years the prices will be much lower and they could be very effective..