The way I use sphagnum moss is to first completely soak it, then put a good amount (leaving room for the snake) into a container* of appropriate size that
has a doorway cut into it (on the top). * Food storage containers that are rectangular & overall sorta flat are what you're looking for. If you put such moss just
on top of aspen, you'll just have soggy aspen. You could also use a container* with no top on it for easier access, but it will dry out faster & may not feel secure
enough to your snake. No way to know how long your moss will last...it can be re-soaked a number of times...when it seems old, toss it. If a little mold appears
it's not lethal or harmful...trust me, there's mold in the wild too.