Pour one standard yogurt container, about 6 ounces, into a food processor.
Add a 4-inch section of fresh moss into the food processor. Pulse the two together for 10 seconds.
Brush the moss-yogurt mix on the stone using a paint brush. Reapply the mix every other day until all the mix has been used.
Keep the treated stone in a damp place outdoors. Avoid scrubbing the stone or hosing it down with water until the moss appears.
Mix 1 pint of milk, 1 teaspoon of flour, 1 teaspoon of yeast, 1/2 teaspoon of plain gelatin, 1 tablespoon of green algae powder, and 1/16 teaspoon of liquid fertilizer in a medium-sized sauce pan.
Bring the ingredients together a boil. Turn off the heat and allow the ingredients to cool completely.
Sprinkle in 2 teaspoons of lichen flakes and 2 teaspoons of potting soil to the cool mixture. Mix the ingredients together with a spoon.
Apply the lichen mixture to the stone using a paintbrush. Store the clearly labeled leftovers in the refrigerator until you are ready to use. Apply the mixture every other day until it is all used.