In Android 4.4 KitKat, Google has disabled the ability to place widgets on the lock screen by default. Instead, users will first need to enable an option, before they can start using widgets on their lock screen.
Considering how few people use lock screen widgets, disabling them out of the box does make sense.
Either way, to use lock screen widgets in Android 4.4 KitKat, you will first need to head over to Settings -> Security and select the option to ‘Enable widgets’. After this, you can easily add lock screen widgets by simply swiping from left to right on the lock screen and then tapping the + symbol.
Sadly, Google still does not provide an option to maximize lock screen widgets by default, which would have made them much more useful. Here is hoping Google tweaks how lock screen widgets work with the next version of Android.