diff --git a/hosts/genepi/default.nix b/hosts/genepi/default.nix
index 97d642c..d960092 100644
--- a/hosts/genepi/default.nix
+++ b/hosts/genepi/default.nix
@@ -30,4 +30,10 @@
       home-manager.users.rpqt = ./home.nix;
     }
   ];
+
+  nix.gc = {
+    automatic = true;
+    dates = "weekly";
+    options = "--delete-older-than 30d";
+  };
 }