diff --git a/tools/prod-flower.sh b/tools/prod-flower.sh
index 5db436df..2b58056a 100755
--- a/tools/prod-flower.sh
+++ b/tools/prod-flower.sh
@@ -10,7 +10,7 @@ cd /backend
   python manage.py wait_for_db
 
   echo "Starting flower"
-  if [[ -n "${FLOWER_BASIC_AUTH}" ]]; then
+  if [[ -n "${FLOWER_BASIC_AUTH:-}" ]]; then
     celery --app=config flower --basic_auth="${FLOWER_BASIC_AUTH}"
   fi
 )
diff --git a/tools/run.sh b/tools/run.sh
index 4e87372a..9f52cd45 100755
--- a/tools/run.sh
+++ b/tools/run.sh
@@ -44,7 +44,7 @@ celery --app=config worker --loglevel=INFO --concurrency="${CELERY_WORKERS:-1}"
 celery_pid="$!"
 
 echo "Starting flower"
-if [[ -n "${FLOWER_BASIC_AUTH}" ]]; then
+if [[ -n "${FLOWER_BASIC_AUTH:-}" ]]; then
   celery --app=config flower --basic_auth="${FLOWER_BASIC_AUTH}" &
 fi