my $nice = { foo => 'bar', baz => 'qux' };
my $mice = "three blind";
my %hitsdb = (
   nice => "$nice",  # this is the problem
   mice => "$mice",  # this is a bad habit
);

print Dumper \%hitsdb;

__END__
$VAR1 = {
          'nice' => 'HASH(0x80f8a20)',
          'mice' => 'three blind'
        };