Configuring phpPgAdmin and pg_ctl reload

I'm setting up phpPgAdmin and I finally get to the point where you
reconfigure pg_hba.conf  One of the lines says to reload the values,
type the command pg_ctl reload.  I try it as super user, no go, I su
into postgres, it complains:

pg_ctl reload
pg_ctl: no database directory specified and environment variable PGDATA
unset
Try "pg_ctl --help" for more information.


Keeping in mind that I typed just what pga_hba.conf said, was there a
step I was missing (I ended up restarting the server and that worked).