BRILLIANT! How to Make Moss Graffiti
Gather up as much moss as you can find or buy. Where you gather the moss is important. The kind that grows on trees won't necessarily do well on walls.
Wash the moss to get as much soil out of the roots as possible.
Break the moss apart. Break into manageable pieces. Then place the pieces in the blender.
Add the buttermilk/yogurt, water/beer and sugar. Blend the mixture until completely smooth. You'll want it to have a paint-like texture.
Alternatively, use one cup of ordinary milk to 1 to 2 tablespoons of moss.
Pour mixture from the blender to a bucket. Whizz around but do not liquefy it because the moss cells must stay intact.
Use a paintbrush to apply the moss-paint to the surface on which you wish your design to grow.
If possible, check back weekly to either spray the design with water (to encourage moss growth, especially if you live in a dry environment) or apply more moss-paint.
Check your moss graffiti regularly. Depending on your climate, sometimes it takes a while to grow your moss.