diff --git a/backend/src/routes/productSpreaderSettings.js b/backend/src/routes/productSpreaderSettings.js
index 778c248..37b3d15 100644
--- a/backend/src/routes/productSpreaderSettings.js
+++ b/backend/src/routes/productSpreaderSettings.js
@@ -11,10 +11,10 @@ const spreaderSettingSchema = Joi.object({
   productId: Joi.number().integer().positive().optional(),
   userProductId: Joi.number().integer().positive().optional(),
   spreaderBrand: Joi.string().max(100).required(),
-  spreaderModel: Joi.string().max(100).optional(),
+  spreaderModel: Joi.string().max(100).allow(null, '').optional(),
   settingValue: Joi.string().max(20).required(),
-  rateDescription: Joi.string().max(200).optional(),
-  notes: Joi.string().optional()
+  rateDescription: Joi.string().max(200).allow(null, '').optional(),
+  notes: Joi.string().allow(null, '').optional()
 }).xor('productId', 'userProductId'); // Must have either productId or userProductId, but not both
 
 const idParamSchema = Joi.object({