Hey there, I've done a few bioactive enclosures in the past for a variety of species of reptiles (geckos, my skink, etc)
Big things to look into with skinks (at least in my experience):
- Drainage layer. Super important so that the soil/bedding isn't constantly wet. Watch for mold and make sure to toss out any moldy plants, wood, etc. Also make sure your enclosure is waterproofed at the bottom (aquarium silicone works great if you need to seal yours!)
- Springtails and isopods are your best friend! They act as a clean up crew and help aerate your bedding (that way its easier for your skink to burrow)
- Plants are definitely fun but just be careful to get safe plants (mine doesn't like veggies but occasionally still chews on the plants in his enclosure)
I see you also have a Harm so I recommend checking out
Josh's Frogs for some good reptile safe plants. I definitely would go for something that is more tropical and enjoys that high humidity. Moss is awesome too!
- If you're going for a very natural look, you can do cork bark and natural woods (as long as you properly sanitize them) along with stuff like slate for rocks (slate holds heat well and works great for my basking spots!)
EDIT: Since skinks burrow, just beware of plants and know they may dig them up. I personally found a lot of luck with vines that drape down vs ground foliage!
