diff --git a/ckanext/odsh/validation.py b/ckanext/odsh/validation.py
index 1a54348b3706013990d51489261f3f247b03cd41..f7139c51e86698c3f6bb23d816e0546f6425e8e1 100644
--- a/ckanext/odsh/validation.py
+++ b/ckanext/odsh/validation.py
@@ -79,6 +79,8 @@ def validate_extras(key, data, errors, context):
         errors=extra_errors
     )
     
+    is_date_start_before_date_end(data, extra_errors)
+    
     validate_extra_date_new(
         key=key,
         field='issued',
@@ -104,6 +106,12 @@ def validate_extras(key, data, errors, context):
     if len(extra_errors.values()):
         raise toolkit.Invalid(extra_errors)
 
+def is_date_start_before_date_end(data, extra_errors):
+    start_date = _extract_value(data, 'temporal_start')
+    end_date = _extract_value(data, 'temporal_end')
+    if start_date and end_date:
+        if start_date > end_date:
+            extra_errors['temporal_start'] = extra_errors['temporal_end'] = 'Please enter a valid period of time.'
 
 def _set_value(data, field, value):
     key = None