Write below code in your viewDidLoad
self.navigationController.toolbar.barTintColor = [UIColor redColor];
It will set red color as your tool bar background.
Reference link https://web.archive.org/web/20160321155823/https://developer.apple.com/library/ios/documentation/userexperience/conceptual/TransitionGuide/Bars.html#//apple_ref/doc/uid/TP40013174-CH8-SW5
In it they said that Use barTintColor to tint the bar background.
