Triggering a Capacitance switch -- Touch switch with Arduino?

I'm working on a project to use a humidifier with a humidity sensor and Arduino for a gardening project.

The issue is that the power switch for the humidifier is a single wire Capacitance switch and I'm having a bear of a time triggering it. I've tried shorting it to ground and +5v with no luck so far.

Apart from bypassing the switch IC, any tips?

Try connecting it to ground through a capacitor. A value of 1nF should do.