When using grow lights it is very important to use a timer.
There are 2 types of timers
Mechanical timers have plastic tabs that are set for the time you want to have the grow light off and on. Please not between brands as tabs down can mean lights off on one brand and on on another. After setting plug in light(switch on if applicable) and spin timer dial to ensure correct settings.
Digital timers you set the time you want the lights to off and on digitally using buttons and a screen.
If using grow lights without the help of the sun it is recommended to have the lights on for 18 hrs and off for 6 hrs in vegetative plant stage. In flower stage 12 hrs on and 12 hrs off. You can also grow light to make up this time difference if growing by a window.
Note some types of plants do not like their “OFF” time interrupted by light.