diff --git a/src/lib/Hydra/Controller/Jobset.pm b/src/lib/Hydra/Controller/Jobset.pm
index 4947f982..1d1cce63 100644
--- a/src/lib/Hydra/Controller/Jobset.pm
+++ b/src/lib/Hydra/Controller/Jobset.pm
@@ -220,6 +220,9 @@ sub updateJobset {
     my $enabled = int($c->stash->{params}->{enabled});
     die if $enabled < 0 || $enabled > 2;
 
+    my $shares = int($c->stash->{params}->{schedulingshares} // 1);
+    error($c, "The number of scheduling shares must be positive.") if $shares <= 0;
+
     $jobset->update(
         { name => $jobsetName
         , description => trim($c->stash->{params}->{"description"})
@@ -232,7 +235,7 @@ sub updateJobset {
         , keepnr => int(trim($c->stash->{params}->{keepnr}))
         , checkinterval => int(trim($c->stash->{params}->{checkinterval}))
         , triggertime => $enabled ? $jobset->triggertime // time() : undef
-        , schedulingshares => int($c->stash->{params}->{schedulingshares})
+        , schedulingshares => $shares
         });
 
     $jobset->project->jobsetrenames->search({ from_ => $jobsetName })->delete;