diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
index 973b7615466b0..fde98bf19ff42 100644
--- a/activerecord/lib/active_record/attribute_methods.rb
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -179,10 +179,10 @@ def define_write_method(attr_name)
         def define_write_method_for_time_zone_conversion(attr_name)
           method_body = <<-EOV
             def #{attr_name}=(time)
-              if time
-                time = Time.zone.parse(time) rescue time unless time.acts_like?(:time)
-                time = time.in_time_zone if time.acts_like?(:time)
+              unless time.blank? || time.acts_like?(:time)
+                time = time.is_a?(String) ? Time.zone.parse(time) : time.to_time rescue time
               end
+              time = time.in_time_zone rescue nil if time
               write_attribute(:#{attr_name}, time)
             end
           EOV
diff --git a/activerecord/test/cases/attribute_methods_test.rb b/activerecord/test/cases/attribute_methods_test.rb
index ab9abf27f9cd1..c336fd9afbcb4 100755
--- a/activerecord/test/cases/attribute_methods_test.rb
+++ b/activerecord/test/cases/attribute_methods_test.rb
@@ -186,6 +186,14 @@ def test_setting_time_zone_aware_attribute_with_string
       end
     end
   end
+  
+  def test_setting_time_zone_aware_attribute_to_blank_string_returns_nil
+    in_time_zone "Pacific Time (US & Canada)" do
+      record   = @target.new
+      record.written_on = ' '
+      assert_nil record.written_on
+    end
+  end
 
   def test_setting_time_zone_aware_attribute_interprets_time_zone_unaware_string_in_time_zone
     time_string = 'Tue Jan 01 00:00:00 2008'