The Dos and Donts of Expanded Clay Pebbles By Zach Zeifman Expanded clay pebbles have been a staple of hydroponic systems for years. 안전하고 사용하기 쉬우며 식물이 번성하는 데 필요한 영양분을 충분히 공급해 줍니다. But thats only if youre going about it the right way.