diff --git a/config/c3d2.nix b/config/c3d2.nix
index 3a20bb5b..6a14e3a4 100644
--- a/config/c3d2.nix
+++ b/config/c3d2.nix
@@ -133,6 +133,7 @@ in {
       gc = {
         automatic = true;
         dates = "06:00";
+        options = "--delete-older-than 21d"
         randomizedDelaySec = "6h";
       };
       package = pkgs.nixUnstable;