Moss graffiti, also known as eco-graffiti and green graffiti, consists of wall decoration using moss.
One or two clumps (about a small handful) of moss
2 cups of buttermilk
You can also substitute with yoghurt (vegan yoghurt can be used)
2 cups of water
1/2 tsp. sugar
Corn syrup (optional)
Place the washed, broken up moss in the blender. Add the two cups of buttermilk, the two cups of water, and the half teaspoon of sugar. Blend this mixture until it is completely smooth. Now, use the paintbrush to test the consistency of the blended mixture. If it drips like paint with too much moisture, add corn syrup then blend the mixture again. Repeat this step until sufficiently viscous consistency is achieved. If the mixture becomes too thick, this can easily be remedied by adding water. Paint the mixture onto the wall in the desired format or picture.
The first couple of weeks are critical. The moss graffiti should be misted using a water spray once every other day to keep it moist. On days when it is not to be misted with water, apply an additional coat of moss paint mixture. The best time to put up a moss graffiti are the spring and autumn seasons. There is sufficient moisture in the air so misting or applying a new coat of moss paint may be done once a week. Monitor the moss graffiti on a regular basis to ensure it stays moist. This will encourage its growth.
There are some articles that say that it is more difficult than it sounds: