Disabling all lock screen notifications
To disable this you will need to go to the Notifications and uncheck Show notifications on lock screen. There is no global disable, so you will have to do this for each app. To get there:


Click the Apple icon in the upper left hand corner
Click on System Preferences
Click on Notifications
Click on the App you don't' want to see notifications from.
Under the alert style, uncheck the box for Show Notifications on Lock Screen.


That will removal all the notifications from your lock screen.