How should a father explain puberty to his daughter?

it's good that you want to take it up and discuss with your daughter. while mostly a mom would do this, it is nice that you are going to talk to her about it. i think keep it as casual as you can, and speak to her in a way that she feels it is natural and not something she should be concerned about. tell her that as she grows, there will be some changes in her body that will come with some physical changes. you can get her some books that talk about the same.