diff --git a/nixng/containers/hydra/hydra.nix b/nixng/containers/hydra/hydra.nix
index ecc3edb..9821815 100644
--- a/nixng/containers/hydra/hydra.nix
+++ b/nixng/containers/hydra/hydra.nix
@@ -46,6 +46,7 @@ makeSystem {
           minimumDiskFreeEvaluator = 100;
 
           dbiFile = "/local/dbi";
+          config.evaluator_max_memory_size = "2048M";
         };
         services.socklog = {
           enable = true;
@@ -66,6 +67,19 @@ makeSystem {
           enabled = true;
         };
 
+        services.crond.crontabs.autogc = {
+          jobs =
+            let
+              storegc = pkgs.writeShellScript "storegc"
+                ''
+                  nix-collect-garbage -d
+                '';
+            in
+              [
+                "0 4 * * * ${storegc}"
+              ];
+        };
+
         init.services.nix-daemon.environment.PATH = with pkgs;  lib.makeBinPath [
           utillinux
           runit