
On tuff anything will grow, as it stays so wet all the time

Lichen on bluestone

under the right conditions lichen is also known to grow on a car

…or even on a car window
In September 2015 I already wrote a post containing a piece about artificial aging of concrete, stone and the like with a moss recipe. Apparently it doesn't work all that well. The moss dries out quickly, and the photo that I linked to was rigged: someone had cut out some moss and pasted it on a wall, something quite different from growing moss. …Read the whole article…