Research went into this it was found 18/6 was the best out of all the light cycles. It's not totally natural, but it promotes plant growth most.

The dark period is important as when the plant rests from the sun it seems to grow up/and leaves grow almost twice as fast than in the light. Least thats what I've heard.

Either way, there should be NOTHING wrong with running 24/0 and then moving to 18/6 I did it and the plants seem very happy,

Peace,
Denial