Horticultural perlite is clean, sterile, pH neutral, non-flammable, odorless, nontoxic and neither decays nor shrinks – even pests such as insects and fungi can’t destroy it. When bulk perlite is mixed with organic compost, natural soils or composted bark, it helps anchor the roots of young plants so they grow stronger.
While horticultural perlite does retain water and food for the growing plants, it is best used for drainage purposes. A good potting soil should contain at least 25 percent perlite for proper drainage. Since vermiculite retains far more water and food for the growing plant, but does not provide the superior drainage properties of perlite, you can have an even better soil mixture by adding both bulk perlite and vermiculite to your soil.
Horticultural perlite is a lightweight substitute for sand and is very useful in a hydroponic gardening systems. Additionally, it is perfect for seed germination and cutting propagation.