diff --git a/services/maintenance/node-image-sweeper-script.yaml b/services/maintenance/node-image-sweeper-script.yaml
index 76553a1..6e3b02c 100644
--- a/services/maintenance/node-image-sweeper-script.yaml
+++ b/services/maintenance/node-image-sweeper-script.yaml
@@ -17,7 +17,11 @@ data:
       THRESHOLD_DAYS=3
     fi
 
-    cutoff=$(date -d "${THRESHOLD_DAYS} days ago" +%s 2>/dev/null || date -v -"${THRESHOLD_DAYS}"d +%s)
+    cutoff=$(python3 - <<'PY'
+    import time, os
+    print(int(time.time()) - int(os.environ.get("THRESHOLD_DAYS", "14")) * 86400)
+    PY
+    )
 
     RUNNING=$(chroot /host /bin/sh -c "crictl ps -a --quiet 2>/dev/null" | tr -s ' ' '\n' | sort -u | tr '\n' ' ')
     IMAGES_JSON=$(chroot /host /bin/sh -c "crictl images -o json 2>/dev/null" || echo '{}')