what if you give the plant the perfect spectrum and less lumens will it do the same or better or worse it just seems that the spectrum means so much to the plant when vegging and flowering.
They are both very important, think of kelvin as time of year and watts as the power in which its translated. So in answer to your question they are different and need to be understood as so.
The way which growers measure the 'power' of grow lights is called PAR watts (photosynthetically active radiation). This is a measure of the watts of power that can actually be used by the plant to grow. Lumens dont really give a true reflection of how much light the plant can use, since it is actually a measure of the human eye's sensitivity. The amount of light used from a 600w HPS is approx 220-250 PAR watts. Wheras the amount of light from a 200w CFL is 200 PAR watts So naturally the thing to do for max PAR watts would be to use 3 x 200w CFL's
Kelvin is important, but lumens just mean your plant will take longer to grow and will have more problems the lower the lumens