diff --git a/app/controllers/custom_fields_controller.rb b/app/controllers/custom_fields_controller.rb
index df85818..c20516a 100644
--- a/app/controllers/custom_fields_controller.rb
+++ b/app/controllers/custom_fields_controller.rb
@@ -68,6 +68,8 @@ class CustomFieldsController < ApplicationController
     @custom_field = CustomField.new_subclass_instance(params[:type], params[:custom_field])
     if @custom_field.nil?
       render_404
+    else
+      @custom_field.default_value = nil
     end
   end