I called bogus on that guy in Asheville claiming moss paste grows on rocks, now my backyard wall says otherwise
My neighbor Dale kept telling me to blend moss with buttermilk and paint it on the north side of my shed, and I figured it was just some old timer's story. Six weeks and one rainy spell later, that wall is greener than the moss I dug up from the creek bed behind his place. Has anyone tried this on concrete out in full sun, or does the north side thing really matter that much?
Tried the same thing on a concrete retaining wall that gets beat on by sun from about 10 in the morning until 4. It took, but way slower than the shaded spots, and I had to mist it twice a day for the first two weeks or it just dried up and died. North side really does matter because the moss wants damp and cool, not because the sun kills it outright. On full sun concrete you can still make it work if you stay on top of watering and rough up the surface first with a wire brush so the mix has something to grab. Also skip the buttermilk if you can, plain yogurt or even a little beer works the same and does not stink up the yard for a week.