How would you cover the expanding foam?

Hey guys! So I’ve just finished up on a majority of this terrarium and I’m not sure what to do with this expanding foam, I tried silicone and dirt which is what partially worked on the back but it was a very annoying and tedious process, for the sides I’m looking to maybe cover them with moss? I’m not sure whether to make a slurry or just put clumps. If either of these ways or maybe another way or thing to cover it, any suggestion is very much appreciated!!