1 Put a thin layer of potting compost into the bottom of a shallow tray, with no holes in the bottom of it.
2 Hunt for some moss on lawns, walls and between paving slabs.
Look on stones and pieces of bark too.
3 Dig up small pieces of moss and put them on your tray.
Add mossy stones and pieces of bark.
4 Collect some rainwater if you can, but tap water will do,and spray or sprinkle the moss well every day.
Add some shells too.