diff --git a/narwhal/acme_renew/Makefile b/narwhal/acme_renew/Makefile
index 8fc55c7..72ecea0 100644
--- a/narwhal/acme_renew/Makefile
+++ b/narwhal/acme_renew/Makefile
@@ -53,7 +53,7 @@ caladan_sync: renew_certs
 		--human-readable \
 		--rsh "ssh -i $(SSH_KEY)" \
 		--rsync-path="doas rsync" \
-		$(ACME_DIR) \
+		$(ACME_DIR)/ \
 		dags@caladan:$(ACME_DIR)
 
 fugu_sync: renew_certs
@@ -65,7 +65,7 @@ fugu_sync: renew_certs
 		--human-readable \
 		--rsh "ssh -i $(SSH_KEY)" \
 		--rsync-path="doas rsync" \
-		$(ACME_DIR) \
+		$(ACME_DIR)/ \
 		dags@fugu:$(ACME_DIR)
 
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