The fastest growing application for Perlite in the horticultural field is hydroponics or otherwise known as Protected Cropping. Perlite exhibits a unique capillary action in that nutrient rich water can be drawn up from a reservoir through a fine Perlite growing media at the rate that is required by a plant. As a result, plants grown in hydroponic supplies, i.e. Perlite do not suffer from over watering or under watering.
Perlite is a natural occurring mineral in the form of siliceous rock, Perlite ore is found world wide with the best mines located in North America, Greece, Turkey, China and Northern Australia. When the perlite ore is heated at approximately 850⁰-900⁰C it expands up to 20 times its original volume, unlike many other volcanic glasses, making it perfect for use as perlite insulation. This expansion is caused by water that has been trapped within the ore (approximately 4% water content is trapped within the perlite ore) and the water is boiled off when evaporation occurs causing the ore to expand to its particular size. This process is much likened to the making of popcorn in your microwave (yet at a much higher temperature). In the expansion phase, the perlite ore changes from dark shades of black and grey to fluorescent, pearly white shades.