How can I get rid of the green moss that grows between patio cracks?

Use pelletized lime

Give it a good spritz of vinegar.

Pour boiling water on unwanted moss in the cracks. Frying destroys plant tissues, so they’ll die within several days.

Add 1 cup of vinegar to 1 cup of water. Stir in ¼ cup of liquid dishwashing soap. Continue stirring to blend thoroughly. Pour the solution into a plastic spray bottle for a highly effective contact killer if any residual growth pops back up later, though a little more boiling water from the tea kettle usually does the trick also.

Try pouring boiling salt water between the cracks, should kill the weeds.

Buy Lilly Miller Moss Out in the bottle that you hookup to your hose. Spray the area. When it turns black use a stiff broom and/or rake to get rid of it.