diff --git a/slices.go b/slices.go
index fafda53..eabe60f 100644
--- a/slices.go
+++ b/slices.go
@@ -7,7 +7,7 @@ import (
 )
 
 func StringSlice(key, sep string) []string {
-	if v, ok := os.LookupEnv(key); ok {
+	if v, ok := os.LookupEnv(key); ok && strings.TrimSpace(v) != "" {
 		return strings.Split(v, sep)
 	}
 	return []string{}