diff --git a/django/db/backends/postgresql/client.py b/django/db/backends/postgresql/client.py
index 3d0d7a0d2a..8123ec7848 100644
--- a/django/db/backends/postgresql/client.py
+++ b/django/db/backends/postgresql/client.py
@@ -2,13 +2,14 @@ from django.conf import settings
 import os
 
 def runshell():
-    args = ['']
-    args += ["-U%s" % settings.DATABASE_USER]
+    args = ['psql']
+    if settings.DATABASE_USER:
+        args += ["-U", settings.DATABASE_USER]
     if settings.DATABASE_PASSWORD:
         args += ["-W"]
     if settings.DATABASE_HOST:
-        args += ["-h %s" % settings.DATABASE_HOST]
+        args.extend(["-h", settings.DATABASE_HOST])
     if settings.DATABASE_PORT:
-        args += ["-p %s" % settings.DATABASE_PORT]
+        args.extend(["-p", str(settings.DATABASE_PORT)])
     args += [settings.DATABASE_NAME]
     os.execvp('psql', args)