Don't use stuff "from outside" like topsoil or plants in a hydro system, you want it to be as clean and sterile as possible, to not bring in any parasites, harmful bacteria or fungi, or molds to take over and possibly harm your system/plants.
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I'm assuming you mean hydroponics? They're far from being ph neutral (acidic, if memory serves) so you'd have an awful time balancing out you ph levels. They'll decompose, too. Perlite is cheap and easy to get, you're plants will be much happier if you use something like that.