I'm sorry if this has been covered repeatedly, but I can't find it using the search - maybe I'm not using the right terms.
I'd like to make 3 or more spheres in various sizes to grow moss in a shady spot outdoors - maybe hidden from view and left to be "discovered" by anyone wandering into the back corners of my small garden. Ideally they'd be light enough to move around occasionally, too. It seems like hypertufa would be perfect for this, although I assume the mix would need to be adapted a bit to foster the moss growth.
I've found a few threads that mention different balls to use (or to avoid) but not found complete instructions. Does the mix go inside the ball, or is it layered on the outside? Is there a way to re-use the ball? Would it be useful to make a core out of something that could hold (and slowly dispense) water, so I would not have to work so hard to keep the moss moist?
Here's what I have in mind:
I also posted something about this on my "regular" forum, New England gardening, but there are no hypertufa folks there. Any advice would be greatly appreciated!