Are you worried that your organ blog posts won't be original? Is this the reason which keeps you from blogging?
You see, no one who wants to be original will ever attain originality. Originality is not the point.
The point is to share your experiences. Look around. What do you see?
How about this:
What are you currently working on as an organist?
What are you or others struggling with in the organ world?
What is inspiring to you or others about organ music that you played today?
Could you write about that?
Just imagine talking to an organist friend when both of you are drinking a cup of cappuccino together. This is all you need to be sincere.
It's your turn to be yourself. Always.