The weathering process of rock, stone and hypertufa all create a similar patina – darkening, moss encroachment, or (if you’re lucky) the growth of lichen all combine to give the look of age to items made with these materials.
You can speed up the look of weathering on your rustic garden art by applying some simple sprays to encourage the moss and lichen to grow.
Soak or spray the item using plain water before you attempt to get moss to grow, to get rid of the alkalinity of the cement.
You can spray it with vinegar diluted with water to increase the acidity; these types of organisms prefer an acid base.
Keep the piece in the shade, especially in hot sunny areas to help the moss get a foothold.
Once it's cooled, you can spray this on the rock or hypertufa, and the glutinous mixture will allow the spores of moss to stick to it and give it a start to grow on. After it's established, the moss will continue growing on the hypertufa.
Keep the item in shade if possible, and spray with plain water in really dry times, and you’ll quickly see the sheen of green which is tiny little moss plants colonizing it.
Try these simple ways to get the weathering process started with your hypertufa projects and rustic garden art, rock benches or stone lanterns, making them look old, even if they’re not.