An adjustable LED lighting system includes a plurality of LEDs, at least one driver, and a programmable signal generator to control a drive frequency. The signal generator includes a clock, an input module to receive commands for driving the LEDs, and a frequency adjustment module to drive the frequency of the one or more LEDs. The LEDS are driven at a target or specified frequency for a time period that is specified with a start time and/or an end time. The LED lighting system allows for a variable frequency of outputs during different time periods and/or in response to specific use commands. The LED lighting system includes one or more target frequencies for one or more target time periods. The LED lighting system stores the target frequencies and target time periods and make the frequency modifications at the user-specified times.