diff --git a/variables-module.nix b/variables-module.nix
index e69673f..ead690e 100644
--- a/variables-module.nix
+++ b/variables-module.nix
@@ -142,7 +142,7 @@ in
           Root SSH Keys
         '';
         type = types.nullOr (types.listOf types.str);
-        default = [];
+        default = [""];
       };
       passwordAuthentication = mkOption {
         description = ''