diff --git a/plugins/calendar/drivers/kolab/kolab_calendar.php b/plugins/calendar/drivers/kolab/kolab_calendar.php
index 408fd3cb..3c0f6151 100644
--- a/plugins/calendar/drivers/kolab/kolab_calendar.php
+++ b/plugins/calendar/drivers/kolab/kolab_calendar.php
@@ -24,6 +24,7 @@ class kolab_calendar
   public $ready = false;
   public $readonly = true;
   public $attachments = true;
+  public $alarms = false;
 
   private $cal;
   private $storage;
@@ -56,10 +57,11 @@ class kolab_calendar
 
     $this->ready = !PEAR::isError($this->storage);
 
-    // Set readonly and editable flags according to folder permissions
+    // Set readonly and alarms flags according to folder permissions
     if ($this->ready) {
       if ($this->get_owner() == $_SESSION['username']) {
         $this->readonly = false;
+        $this->alarms = true;
       }
       else {
         $acl = $this->storage->_folder->getACL();
diff --git a/plugins/calendar/drivers/kolab/kolab_driver.php b/plugins/calendar/drivers/kolab/kolab_driver.php
index 935c7600..bda22f3c 100644
--- a/plugins/calendar/drivers/kolab/kolab_driver.php
+++ b/plugins/calendar/drivers/kolab/kolab_driver.php
@@ -503,13 +503,22 @@ class kolab_driver extends calendar_driver
    */
   public function pending_alarms($time, $calendars = null)
   {
+    if ($calendars && is_string($calendars))
+      $calendars = explode(',', $calendars);
+
     $events = array();
-    foreach ($this->load_events($time, $time + 86400 * 365, $calendars) as $e) {
-      // add to list if alarm is set
-      if ($e['_alarm'] && ($notifyat = $e['start'] - $e['_alarm'] * 60) <= $time) {
-        $id = $e['id'];
-        $events[$id] = $e;
-        $events[$id]['notifyat'] = $notifyat;
+    foreach ($this->calendars as $cid => $calendar) {
+      // skip calendars with alarms disabled
+      if (!$calendar->alarms || ($calendars && !in_array($cid, $calendars)))
+        continue;
+
+      foreach ($calendar->list_events($time, $time + 86400 * 365) as $e) {
+        // add to list if alarm is set
+        if ($e['_alarm'] && ($notifyat = $e['start'] - $e['_alarm'] * 60) <= $time) {
+          $id = $e['id'];
+          $events[$id] = $e;
+          $events[$id]['notifyat'] = $notifyat;
+        }
       }
     }