A grow light system for growing plants. The grow light system can have a carrier board assembly containing a plurality of apertures and a plurality of LED modules removably engaged with the carrier board in the apertures and forming a gap between LED module and the carrier board. The grow light system can be configured to draw air through the gap over the LEDs and along the heat sink fin to reduce the temperature of the LED module. A plurality of the LED modules can be connected in series and the carrier board can include a dedicated receptacle for a single LED module that is not connected in series with the remaining LED modules.