diff --git a/src/Model/BlogPost.php b/src/Model/BlogPost.php
index 4b88049..dedbd66 100644
--- a/src/Model/BlogPost.php
+++ b/src/Model/BlogPost.php
@@ -69,6 +69,13 @@ class BlogPost extends Page
         'Summary'     => 'HTMLText'
     ];
 
+    /**
+     * @var array
+     */
+    private static $indexes = [
+        'PublishDate' => true,
+    ];
+
     /**
      * @var array
      */