diff --git a/README.md b/README.md
index 3afd118..8a55cff 100644
--- a/README.md
+++ b/README.md
@@ -242,7 +242,9 @@ systemctl --failed
 * https://nixos.org/manual/nix/stable/package-management/garbage-collection.html
 * https://discourse.nixos.org/t/why-doesnt-nix-collect-garbage-remove-old-generations-from-efi-menu/17592/4
 
-For all profiles:
+This is automated in [base.nix](modules/base.nix) with the `nix.gc` option.
+
+Run manually for all profiles:
 
 ```shell
 sudo nix-collect-garbage --delete-older-than 14d
diff --git a/modules/base.nix b/modules/base.nix
index 1b3babc..11b5aac 100644
--- a/modules/base.nix
+++ b/modules/base.nix
@@ -121,6 +121,13 @@
 
   nix.settings.auto-optimise-store = true;
 
+  # https://nixos.wiki/wiki/Storage_optimization#Automation
+  nix.gc = {
+    automatic = true;
+    dates = "weekly";
+    options = "--delete-older-than 7d";
+  };
+
   # Firewall.
   # https://nixos.wiki/wiki/Firewall
   # -> Firewall rules may be overwritten by docker, as per https://github.com/NixOS/nixpkgs/issues/111852