Definition - What does lighting schedule mean?
A lighting schedule is the cycle of light and dark that is used with the cannabis plant in different phases of their growth. The recommended lighting schedules can vary, and for many it is determined by experience as well as available resources.
MaximumYield explains lighting schedule
In the vegetative state, which is the first period of growth, plants can be kept under lights for 18 hours or more. This is then balanced with 6 hours of darkness. The light helps give the plants energy to grow, while the plant produces sugars in the dark phase. Some growers will have their plants under lights for 24 hours in the initial phase to help them get as big as possible. The plants won't begin to flower unless they receive about 12 hours a day of darkness
In the flowering phase, the lighting schedule is switched to a 12/12 cycle.