No enclosing instance of (class here) is accessible

I have a class called GreenhouseControls that has a bunch of

classes built into it such as:

public class ThermostatNight extends Event {
    public ThermostatNight(long delayTime) {
      super(delayTime);
    }
    public void action() {
      // hardware control code here.
      thermostat = "Night";
    }
    public String toString() {
      return "Thermostat on night setting";
    }
  }

I pull values from a text file to get event names such as "ThermostatNight" and time values such as "2000". To instantiate a new object with those values I built a EventFactory that accepts the values as arguments.

This is the class I have built to create new event objects from text file values:

    public class EventFactory{

        public static Event createSpecificEvent(String eventName, long delayTime) {

            Event event = null;

            switch(eventName) {
            case "ThermostatNight": 
                event = new ThermostatNight(delayTime); // Compiler error
                break;
            case "ThermostatDay": 
                event = new ThermostatDay(delayTime);
                break;
            case "LightOn": 
                event = new LightOn(delayTime);
                break;
            case "LightOff": 
                event = new LightOff(delayTime);
                break;
                ...
        }
}

Everything was working well when I ran the program until I pulled the EventFactory class out of GreenhouseControls and into it's own independent class. Now I am getting a compile time error that says:

"No enclosing instance of type GreenhouseControls is accessible. Must qualify the allocation with an enclosing instance of type GreenhouseControls (e.g. x.new A() where x is an instance of GreenhouseControls)."

See in-line comment in EventFactory class to see where the error occurs at "new ThermostatNight(delayTime)"