Helen Nodding's Moss Gaffiti Recipe 1 can of beer OR yogurt or buttermilk 1/2 tsp sugar Several clumps garden moss plastic container with lid blender paintbrush crumble moss into a blender. Add nutrients & blend to create a smooth, creamy consistency. Pour into plastic container. Place stencil on damp and shady wall Paint moss milkshake into design on wall. Keep moist for weeks and weeks until the bits of blended moss begin to grow.