diff --git a/README.md b/README.md
index 25a191d..ed4efef 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ pg_new=$(nix-build --no-out-link -A postgresql_$((old+1)) '<nixpkgs>')
 ```
 3. Initialize new data directory
 ```bash
-$pg_new/bin/initdb --encoding=UTF8 --no-locale $((old+1))
+$pg_new/bin/initdb --encoding=UTF8 --locale=C $((old+1))
 ```
 4. Run check
 ```bash