no because you set the times your self! as in turn the lights on for 18 hours and off for 6 while you grow the plant to the size you want, then turn the lights to 12 on 12 off to start the flowering.
Well depending on the climate you live in it could be better to grow in the winter if you live in a warm climate so you are not fighting heat issues in your closet and if you live up North the opposite is true. Good Luck.
the most popular is 18/6 for veg and always 12/12 for flower, but some people do 20/4 veg or 24/0 veg but 18/6 is fine and saves you the 6 hours of electric.