Cobblestone
Cobblestone is a round rock of uneven shape and size. It is inorganic and does not absorb water to any significant degree. Cobblestone is great as drainage in the bottom of a pot or as an ingredient in an inorganic rock mix. For Dendrobiums and other tall orchids that have a tendency to tip over, cobblestone can be the ideal substitute for styrofoam packing peanuts in the bottom of a pot providing drainage, weight, and support.
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