the people who sell LED grow lights lie so much about there potential that it makes it difficult to have sensible discussion about LED's. We all know that 90w LED does not equal 400w HPS, and in fact 400w HPS is better than 400w LED.
Yeah for sure. The thing with lighting is that it almost needs to be framed in two conversations. Vegging and flowering. This is because the results vary so dramatically. An example of this is LED lighting during vegatative growth. A 150 watt LED lamp that is an array of LEDs layed out of 800mm x 600mm area emitting 4000 lumens per square foot, will veg plants as good as a 400w metal halide will....up to a certain height.
After plants have passed the best potential height which is just over a foot under LEDs, then the metal halides will excell and the LEDs will drop back lack in penetrative light.
But in saying that, most growers will veg to a foot anyways before switching, so in those circumstances it is true to say that the LED array as I explained would match the metal halide even though you are only spending 150 watts of LED lighting.
However once you switch to flowering the demands from the plant to propgate big bud surpass what any LED lamp on the market can deliver.
Not only do the plants need 10,000 lumens per square foot of light to produce enough photosynthesis to build big bud, they also need the intensity as a means of generating resistance against the light intensity. The resistance is of course resin which the plants produce to protect them against the intensity of lumens.
So to me it is just being too simplistic when people say LEDs are better or worse than some other form of lighting.
The results say everything to me. I have vegged nice bushy tightly noded 1 foot plants under LEDs, floros and HIDs. But only flowered real big bud under HIDs, although when I flowered with floros the one time I did get 2.75 oz per plant.