How to Make Concrete Look Aged

Mix a batch of bacteria in a bucket using a one-to-one ratio of yogurt and buttermilk.

Paint the bacterial mixture onto the concrete in the patches where you wish to age the material. Apply a solid coating of the mixture to the concrete, covering the surface completely enough that the concrete beneath no longer shows through.

Rub sheet moss onto the wet bacterial mixture. The bacteria in the mixture will act as a growth accelerant for the moss, allowing it to attach quickly to the stone. You can purchase sheet moss from a garden center.

Cover the moss with a loose layer of plastic sheeting. Attach the plastic with masking tape so that it stays in place, but space openings along the edges to allow for airflow. The sheeting will keep the moss wet as it attaches to the stone.

Remove the sheeting every three to five days, and spray a light mist of water onto the moss. Once the moss has attached firmly to the stone, remove the sheeting and allow it to grow naturally, giving an aged look to the stone.