I'm going to go against everthning you may have heard about
lights. I ran a test this summer with tomatoes out side and inside with full sun no shade. my inside plants grew twice as big fruited first the out side in natural light.
my
bulbs are the cheap $1 at lowes f32 4ft bulbs and my lumens meter reads about 1200 in the center of my light fixture. plants grow fine
to compare i have a system that grows just as well with 1200 watts
hps on light rail movers. just cost me more money.
I now believe its the closeness to the light that makes it less money to run. hps put out lots of light but you have to keep it so far away. in florecent the plant can grow right on it.
To much energy being used on heat rather than light out put. and to be fair my 1200 wat hps is in a position of where i run 768 watts of florecents so its a savings of a third. but no light movers, no a/c just fans. its as good and cheaper in the long run.
I now believe and am building a new light fixture for my out door green house that is as simple as one 8 foot florecent bulb mounted right down the center on my grow pot going vertical to the roof and i will be letting the plant envelope the bulb during growth. this way i figure i currently get only part of the bulb shining on the plant so i have to add additional bulbs around it to surround it. now i will have 360 degrees of bulb from one bulb and i belive this will be the same as four bulbs.
with this theory i will go from hps 1200 watts to my current 768 watts to 288 watts. why shine on the plant from the outside when you can go to the center of the plant and shine out all the way around.