diff --git a/apps/collection/models.py b/apps/collection/models.py
index a4a9bcae..928370d7 100644
--- a/apps/collection/models.py
+++ b/apps/collection/models.py
@@ -91,7 +91,9 @@ class GuideQuerySet(models.QuerySet):
 class Guide(ProjectBaseMixin, CollectionNameMixin, CollectionDateMixin):
     """Guide model."""
     parent = models.ForeignKey(
-        'self', verbose_name=_('parent'), on_delete=models.CASCADE)
+        'self', verbose_name=_('parent'), on_delete=models.CASCADE,
+        null=True, blank=True, default=None
+    )
     advertorials = JSONField(
         _('advertorials'), null=True, blank=True,
         default=None, help_text='{"key":"value"}')