What is the best thing to keep a young tegu on, hes only about 6-7 inches. What kind of substrate have you guys found best to use ?

Cypress gets my vote.

Yea thats what im using now, Hes always burrowed under when i come in though. Was wondering if its healthy for him to stay under all the time.

I vote cypress as well.

Hay. Personally, I hate cypress and would not keep anything on it for many reasons.
But, people find what works for them and they use it.

Best thing you can do is try different types and see what you like best and what your animal responds to best.

I have tried all kinds over the years, from simple to complex, to no substrate at all.
I found hay to suit me and my animals needs the best.

for my 2 1/2' columbian i use a non treated potting soil mixed with, sand & hay that is what he likes best for digging. but i have used all the above mentioned when he was small with great results also.

Anyone have any suggestions for substrate for an outdoor enclosure? I've lined the ground and about 1' up the walls with poultry netting (pretty thick green plastic material) so that my two tegus can't dig out through the bottom or sides. (my old outdoor enclosure was elevated off the ground so I didn't have this issue) Under the netting is just topsoil. However, I imagine that when it rains, it's going to become a mud pit. Anyone have any suggestions on what to put atop the topsoil? Was going to cover the netting with another few inches of topsoil and then put something on top of that. Just don't know what to put down. I'm leaning towards hay or cyprus mulch but my fear with using cyprus mulch is that they sometimes ingest it. Any help would be appreciated.