How to make a solid black bar fade out?

[R3XXY]

HI everyone, I'm trying to make a solid black bar at the bottom of a layer to use as a backgrond for text. I'd like the black bar to fade out vertically, but I can't find a way to make a nice smooth fade. I've tried using the Graident tool but the fade out is much too sudden, not a nice gradual fade.

I want to then save that as a project so I can just add in new images and text.

Can anyone help?

TIA