Perlite

Perlite is a volcanic rock that contains between 2% and 5% water. This lightweight material is used to prevent growing media from becoming compacted while promoting good aeration and drainage. For a growing medium mix, 10% perlite is recommended. The remaining portion can be mixed with soil, worm castings, coconut fiber, or peat. It is ideal for plants that require good drainage, such as cacti and succulents; however, it can be used with virtually any type of plant.