diff --git a/backend/src/utils/validation.js b/backend/src/utils/validation.js
index df966a6..05061ff 100644
--- a/backend/src/utils/validation.js
+++ b/backend/src/utils/validation.js
@@ -43,8 +43,8 @@ const lawnSectionSchema = Joi.object({
   name: Joi.string().max(255).required(),
   area: Joi.number().positive().required(),
   polygonData: Joi.object(),
-  grassType: Joi.string().max(100),
-  soilType: Joi.string().max(100)
+  grassType: Joi.string().max(100).allow(null, '').optional(),
+  soilType: Joi.string().max(100).allow(null, '').optional()
 });
 
 // Equipment validation schemas