Horticultural perlite is made by exposing perlite to heat, which causes the trace water contained in the perlite to expand, “popping” the perlite like popcorn and expanding it to 15 times its former size. The final product is a very lightweight, white stone-like substance. The superheated perlite consists of tiny air compartments. This results in an incredibly lightweight material. The end product weighs only five to eight pounds per cubic foot. The porous surface of expanded perlite provides room alternately for both air and water in the mixes each needed for vigorous root growth.

Under a microscope, perlite is revealed as being covered with many tiny cells that absorb moisture on the exterior of the particle, not inside, which makes it particularly useful in directing moisture to plant roots. Perlite is prized for its moisture retention and aeration properties. It is naturally sterile and has a neutral pH.

While both perlite and vermiculite aid in water retention, perlite is more porous and tends to allow water to drain much more readily than vermiculite. This makes perlite a more suitable addition to potting soils for plants that do not require very moist media, such as cactus soils, or for plants that thrive in well-draining soil.

Horticultural Perlite

Application of horticultural perlite:

• Soilless growing media
• Seed starting
• Plant propagation
• Hydroponic growing
• Vegetated roofs
• Stormwater biofiltration
• Turf underlayment
• Native soil amendment etc.