Description For addition to Growing Media, for use in rooting cuttings. Perlite’s honeycomb internal cells help to improve aeration and insulates compost, reducing large temperature fluctuations. Perlite is a glassy volcanic rock, gray and with a pearly shine on the rock’s surface. It consists mostly of silica and has water molecules trapped within it. Perlite P10 fine grade 0.015mm – 2.0mm
