Things You'll Need
Wooden spoon (optional)
Buttermilk or plain yogurt
Garden hose with fine spray nozzle
Mosses are seedless terrestrial plants that love shade and moisture and reproduce by spores. They are easy to grow, if conditions are right, and you can train moss to a vivid green cover for various garden structures with little effort and a lot of water. There are two common ways to start moss growing on a wall -- transplanting patches of moss from another location and mixing moss and an adhesive medium in a blender and painting it on the surface where you want it to grow. A moss smoothie is an easy way to age a stone or brick wall in your garden, as long as sections of the wall get almost complete shade.
Monitor the section of wall where you would like moss to see how much sun it gets during various times throughout the day. Check both sides of the wall; you can plant moss to wander over the top of a wall and down the other side. Choose an area that remains in partial or complete shade.
Dig up a patch of moss from your own property or an accessible area nearby. If there is no available moss, purchase moss at a nursery or buy it online.
Place the moss in a blender with a small amount of water and blend until it forms a thick soup. The amounts can vary -- start with a handful of crumbled moss and an equal amount of water. Experiment with adding moss for enough body so it will stick to a wooden spoon. For greater adhesion to the wall, use 1 cup or more of buttermilk or yogurt instead of water, but add some water if the mix is too thick. Yogurt or buttermilk and moss will adhere to most stone or stucco walls. Water with moss may be enough for a rough-textured wall.
Paint the moss soup on the wall using the paint brush. Slop it on generously, not too thin, so that the area is well-covered but not dripping globs of moss slurry.
Keep the moss "garden" watered until you see thickening patches of green take over. This can take several weeks. Once the moss is established, it will draw moisture from the environment as long as it remains shaded. During drought conditions, continue to mist and water the moss so it won't dry out.
Some gardeners use a raw egg in the moss milkshake so the mix will stick to a smooth wall. Be careful if you use an egg because the mix could glaze and dry quickly. Stay on top of misting for best results.