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They look like plastic plants to me?
If you wanted to grow plants though, you will need some kind of substrate that hold nutrients, or fertilise them in another way. But what you need will depend on the plants that you want to grow, how much light you have, etc.
When I did a soil substrate tank, I used Miracle Gro organic potting mixture. You can cover it with whatever bottom material you like. I used pea-sized polished gravel.
I would only use the poorest top soil you can find, with as little organic matter in it as possible. You can also mineralize it ,which gets rid of the organics but I prefer to try and skip that step.