Well, the recipe I base mine around is one that's meant for monitors. The original recipe is 50% organic topsoil (it comes in like 40 pound bags at homedepot), 25% silica free playsand, and 25% vermiculite. I keep the vermiculite out because uromastyx and beardies tend to be very inquisitive creatures and I'm worried they might try to eat some of it. Vermiculite is only really necessary when you have 18" or more of soil and a full burrowing setup (it helps hold the burrows). For my purposes I need only a thin layer of it for substrate, so I mix just about 1 part sand to 3 or 4 parts organic topsoil At first it seems sort of dark if you're used to white or tan substrates, but you sort of learn to love the darker earthy color after a day or two. If you really don't like it too dark you can add in some more sand and it will lighten up a bit.
Also, you have to water it every few days or else it dries out and turns to dust. If you're using a wooden cage you have to make a liner for it. For my new cages I'm going to make a really thick nice liner out of some shelfliner. The first few layers I'm going to duct tape at all of the seems to really make it waterproof, and then the last layer I'm going to just set over it so the lizards can't get to the duct tape. I want it to be basically a completely waterproof, indestructable liner, so I don't have to change it all of the time.
As for cleaning, I haven't had to clean too much because my uro tends to save her poo until she comes out into my room (which is why there's constantly newpapers and towels around my room), but basically all of the water from the crap is either evaporated (as in any cage) and some of it will go into the dirt, but it's dirt, and even when lots of liquid is released (like with a uro), it just absorbs it to the bottom and for some reason doesn't smell or anything. I think maybe there's good bacteria in the dirt that helps keep it clean. I've had this batch of dirt in there for about 6 monthes or more, and it will remain there until I get the new cages, and even then, I'll transfer probably all of it into the new cage to be mixed with a fresh batch. It just doesn't go bad like other substrates. The only time you have to replace it is if it starts to smell or something, but even though it's been in there so long, it's still just the same as when I put it in there.
I think maybe adding water to it has something to do with it, because the water evaporates after a couple of days (which is why you have to continuously water it), so I think maybe it's taking any nasty stuff with it. I guess that's probably how the bottom of the tank stays clean.
It seems like a good natural solution, and one that some people seem to overlook. I think even lizards that are built to live in sand could probably do well on a soil. I mean, if you don't water it for a while, it basically turns into sand, and it's more natural looking than just straight up sand, you know what I mean? The only downside is that it has rocks in it, so with some species you have to be careful about that, but my uro has never tried to eat them or anything, and I don't think the beardie would either. I think I would actually feel fairly confident feeding my beardie insects on this stuff too. It doens't stick to the crickets like sand does, and I would think that it would pass much easier than sand or another dry substrate.
and that's why I love her!
