lib/PublicInbox/WatchMaildir.pm | 4 +++-

diff --git a/lib/PublicInbox/WatchMaildir.pm b/lib/PublicInbox/WatchMaildir.pm
index 4be0b397217d55334fa6575cbe58b77a6cbdbf51..e49fb6c78d91d71edc59b25462f39974525ed019 100644
--- a/lib/PublicInbox/WatchMaildir.pm
+++ b/lib/PublicInbox/WatchMaildir.pm
@@ -24,7 +24,9 @@ 	# "publicinboxlearn" is legacy but may be supported
 	# indefinitely...
 	foreach my $pfx (qw(publicinboxwatch publicinboxlearn)) {
 		my $k = "$pfx.watchspam";
-		if (my $dir = $config->{$k}) {
+		defined(my $dirs = $config->{$k}) or next;
+		$dirs = [ $dirs ] if !ref($dirs);
+		for my $dir (@$dirs) {
 			if (is_maildir($dir)) {
 				# skip "new", no MUA has seen it, yet.
 				my $cur = "$dir/cur";