Sav, dirt, and burrowing

[hhw]

I have a hatchling Sav (6-8"?) in a 10 gallon tank right now (moving him into something bigger soon). I have some good ol' dirt from my yard as the substrate, about 6" deep. However, my Sav has yet to successfully make any burrows. He's dug away a bit at the corners, but only a little bit.

So, is my Sav too young to burrow? Is there not enough surface area? Or is the consistency of my dirt not quite right? (too sandy, not sandy enough, etc.?).