diff --git a/mod/lesson/lib.php b/mod/lesson/lib.php
index 4b318881fc3..813ff4c4381 100644
--- a/mod/lesson/lib.php
+++ b/mod/lesson/lib.php
@@ -469,6 +469,9 @@ function lesson_grade_item_update($lesson, $grades=NULL) {
         $params['gradetype']  = GRADE_TYPE_VALUE;
         $params['grademax']   = $lesson->grade;
         $params['grademin']   = 0;
+    } else if ($lesson->grade < 0) {
+        $params['gradetype']  = GRADE_TYPE_SCALE;
+        $params['scaleid']   = -$lesson->grade;
     } else {
         $params['gradetype']  = GRADE_TYPE_NONE;
     }