diff --git a/src/wuttjamaican/app.py b/src/wuttjamaican/app.py
index b28b63b..db044b0 100644
--- a/src/wuttjamaican/app.py
+++ b/src/wuttjamaican/app.py
@@ -743,10 +743,11 @@ class AppHandler:
         :param value: A :class:`python:datetime.date` instance (or
            ``None``).
 
-        :returns: Display string, or ``None``.
+        :returns: Display string.
         """
-        if value is not None:
-            return value.strftime(self.display_format_date)
+        if value is None:
+            return ""
+        return value.strftime(self.display_format_date)
 
     def render_datetime(self, value):
         """
@@ -757,10 +758,11 @@ class AppHandler:
         :param value: A :class:`python:datetime.datetime` instance (or
            ``None``).
 
-        :returns: Display string, or ``None``.
+        :returns: Display string.
         """
-        if value is not None:
-            return value.strftime(self.display_format_datetime)
+        if value is None:
+            return ""
+        return value.strftime(self.display_format_datetime)
 
     def render_error(self, error):
         """
diff --git a/tests/test_app.py b/tests/test_app.py
index ebede2e..b17788c 100644
--- a/tests/test_app.py
+++ b/tests/test_app.py
@@ -472,13 +472,13 @@ app_title = WuttaTest
         self.assertEqual(self.app.render_currency(value), '($42.42)')
 
     def test_render_date(self):
-        self.assertIsNone(self.app.render_date(None))
+        self.assertEqual(self.app.render_date(None), '')
 
         dt = datetime.date(2024, 12, 11)
         self.assertEqual(self.app.render_date(dt), '2024-12-11')
 
     def test_render_datetime(self):
-        self.assertIsNone(self.app.render_datetime(None))
+        self.assertEqual(self.app.render_datetime(None), '')
 
         dt = datetime.datetime(2024, 12, 11, 8, 30, tzinfo=datetime.timezone.utc)
         self.assertEqual(self.app.render_datetime(dt), '2024-12-11 08:30+0000')