I also used some of the rich black compost to build up around some of my ginger plants.
I read somewhere that you should remove the flowers and pods so that the plant will form bigger tubers. It is probably a good idea to do that anyway as the flowers and pods are poisonous.
Now I have an empty wheelie bin. When I go to collect my free mulch in a couple of weeks time I will fill it up with mulch. That will be handy to have on hand. I think it works better as a mulch container than a compost bin.