How do it encourage moss growth on concrete / paving ?
Moss needs acidic conditions with lots of shade and moisture. Spraying buttermilk occasionally feeds moss, too. Some people start moss by taking some existing moss, mix it in a blender with some buttermilk, and spray or brush the resultant mixture where they want moss to grow. Another internet moss recipe uses a can of beer and a teaspoon of sugar mixed with the moss. I’ve seen this work amazingly well.
