I'll be doing a miniature bog in a container with just 8 inches of space on top of the "self watering reservoir".
Many people have talked about having a layer of sand, followed by peat, topped by spaghum moss for the layers.
What is the purpose of the layer of sand? Could another media substitute. If it is just to serve as a reservoir for water, could something like lava rocks be used instead? If not, why not?
Alternatively, could I skip the sand layer and just use spaghum with lfs on top?
Inquiring minds want to know the REASONS for the different medias used.