Where can I find Organic Top Soil?

Hello everyone.
We are adopting a Greek Tortoise and we're trying to set up her new home. I've gone online looking at care instructions and most people suggest using Organic Top Soil. We haven't had luck finding it, and we tried going to the home/gardening store but they don't seem to know what an organic top soil is. I wonder if we're looking at the wrong place?

Does anybody know what it's called in Japanese and where can we find one?

Please help, thank you.

First of all, organic topsoil (perhaps you should've omitted the space between "top" and "soil") in Japanese is 有機表土
"Organic" is 有機 (yuuki) and "topsoil" is 表土 (hyoudo)

But to begin with, Greek Tortoise is ギリシャリクガメ (girisha riku-ga-me)
And when I searched the Internet for things you need to keep a ギリシャリクガメ, I found no information suggesting 有機表土. The information I found were suggesting things more specifically, such as ヤシガラマット (yashigara-matto: palm kernel shell mats), ウッドチップ (uddo-chippu: wood chips), or 赤玉土 (akadama-tsuchi) etc. But more importantly, you need a big cage as well as lights and a temperature control system.

If you are keeping the tortoise in Japan, you need to use something for the Japanese climate. Perhaps you should consult with various reptile shops in your area.

Just for your reference, here is a quick Google search result on ギリシャリクガメ　飼育
https://www.google.com/search?ei=n10IXfnyOMWg8QXlkbyQAQ&q=%E3%82%AE%E3...