I heard of some people using something called Nature's way. I am using one that is made by Long island Compost. but I live on Long Island, I do not know if it is available in other places. I would go to the depot or your local (large) garden center) and ask for a Organic top soil. When you find it just make sure there are no additives, check the ingredients. I even called the company to ensure of its safety b/c I also use it for my frogs so it would be even more deadly for them.
Good luck
Christina
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0.0.1 Hatchling Indian Star Tortoise (Sitara)
1.1 Russian Tortoise (Willy & Mikey)
0.1 Ornate Box Turtle (Lily)
1.0 Red Eared Slider (Chester)
0.0.2 White's Tree Frog (Kermit & Phil)
0.0.1 Red eyed Tree Frog (Justin)
0.0.1 Big Eyed Tree Frog
0.0.2 Bubbling Frog
0.0.2 Tiger Leg Tree Frogs (Akari & Shiro)
0.0.3 Amazonian Milky Tree Frogs
0.0.1 Dwarf Megophrys
0.0.2 Rainbow Burrowing Frog/Ornate Hopper
0.0.1 Asian Blue Webbed Gliding Tree Frogs
0.0.1 Albino Pacman Frog
0.1 Praire Dog (Timmy)
0.2 Chinchillas (Layla & Snickers)
0.3 mice
0.1 dog (Holly)
2.0 Cats (Champ & Bear)
Oh and a husband 