Perlite is an ideal compost additive as it helps to retain air in the compost which is essential for healthy root development. It helps to create an optimum balance of air and water, which makes water logging almost impossible and minimises damage to roots when transplanting.
When added to compost it accelerates rooting and reduces the risk of fungal diseases. Perlite is a naturally occurring, non-toxic, volcanic rock that has been heated to a high temperature to produce a lightweight, micro-porous material with a high surface area.
It has been carefully graded to produce a particle size of 2-5mm.