diff --git a/sdk_container/src/third_party/coreos-overlay/app-emulation/rkt/files/rkt-gc.service b/sdk_container/src/third_party/coreos-overlay/app-emulation/rkt/files/rkt-gc.service
index f7c049394e..eb3ebc1e9e 100644
--- a/sdk_container/src/third_party/coreos-overlay/app-emulation/rkt/files/rkt-gc.service
+++ b/sdk_container/src/third_party/coreos-overlay/app-emulation/rkt/files/rkt-gc.service
@@ -4,4 +4,4 @@ Description=Garbage Collection for rkt
 [Service]
 Environment=GRACE_PERIOD=24h
 Type=oneshot
-ExecStart=/usr/bin/rkt gc --grace-period=$GRACE_PERIOD
+ExecStart=/usr/bin/rkt gc --grace-period=${GRACE_PERIOD}