diff --git a/nix/culr-module.nix b/nix/culr-module.nix
index b7ec00a..9e42217 100644
--- a/nix/culr-module.nix
+++ b/nix/culr-module.nix
@@ -26,7 +26,7 @@ in {
     environment.sessionVariables = {
       CULR_PATTERN = let
         serialise = {
-          list = list: concatStringsSep ";" list;
+          list = list: concatStringsSep ";" (map (i: builtins.toString i) list);
           string = s: s;
         };
       in