diff --git a/charts/cnpg-cluster/templates/backup-cron.yaml b/charts/cnpg-cluster/templates/backup-cron.yaml
index 3010f7a..86afa6b 100644
--- a/charts/cnpg-cluster/templates/backup-cron.yaml
+++ b/charts/cnpg-cluster/templates/backup-cron.yaml
@@ -63,5 +63,5 @@ spec:
                 - name: PGHOST
                   value: {{ include "cnpg-cluster.fullname" $ }}-r
                 - name: RETENTION_DAYS
-                  value: {{ .Values.backup.sqlDumpRetentionDays }}
+                  value: "{{ .Values.backup.sqlDumpRetentionDays }}"
 {{- end}}
diff --git a/charts/cnpg-cluster/tests/__snapshot__/cnpg-cluster_test.yaml.snap b/charts/cnpg-cluster/tests/__snapshot__/cnpg-cluster_test.yaml.snap
index 95ed8e1..00775ef 100644
--- a/charts/cnpg-cluster/tests/__snapshot__/cnpg-cluster_test.yaml.snap
+++ b/charts/cnpg-cluster/tests/__snapshot__/cnpg-cluster_test.yaml.snap
@@ -116,7 +116,7 @@ cluster with enabled backup and recovery:
                   - name: PGHOST
                     value: RELEASE-NAME-cnpg-cluster-r
                   - name: RETENTION_DAYS
-                    value: 30
+                    value: "30"
                 image: ghcr.io/socialgouv/docker/s3-client:1.2.0
                 imagePullPolicy: IfNotPresent
                 name: s3-client