clay pebbles are made of 100% natural clay. is inert, pH-neutral, clean and at the same time, decorative. Potting media for Orchids - Used alone or in combination with coconut husk chips, bark, charcoal or other orchid media, porous structure can provide excellent aeration around the roots while its ability to act as a water reservoir will be appreciated by your orchids when water is needed. The size of the pebbles is perfect for medium to large Cattleyas and Laelias. Hydrophonic/Hydroculture media - The capilliarity and the structure of the clay pebbles ensures good root aeration and prevents rotting, excess acidity and soil pests. Drainage - Compared to gravel, is lighter and can act as a water reservoir. can then release the water when its surroundings needed it. Decoration - With its red color and mostly round shape, is often used as a decorative top-layer for indoor plants and outdoor gardens. As a top layer, it will also prevent the top soil from drying out quickly.