Clay pebbles that hold water and nutrients. It is a planting medium popular with gardeners looking to grow plants in a hydroponic system without the use of soil. Using clay pebbles will help speed up plant growth by providing plenty of aeration to the root zone. They also provide a great support structure to give your plants unparalleled stability. It can also be used as a drainage layer in plant pots for semi-hydroponic potting. If placed above as cover layer, it can provide optimum protection against dehydration. Or, it can be used to mix with soil in loosening the potting mix to give adequate aeration to plant roots.