Perlite is primarily used to aerate compost. It excellent for creating a free-draining potting compost for plants that need good drainage, such as cacti and succulents. It can also help create an airy compost for seedlings.
because of these properties, perlite is also popular in orchid, cactus, and succulent planting mixes that like to be on the drier side, and in hydroponic setups as a standalone growing medium.
The perlite can be mixed with a bit of potting soil to keep tall containers from becoming top-heavy, or the perlite can be used by itself as a bottom layer in wide oversize pots. Roots will grow down into the perlite layer whether or not soil is mixed into it.
For container gardens and potted plants, use up to 1/3 perlite per container. Succulents and orchids especially love perlite, and their potting soil can be mixed with half or even more perlite depending on the species. Perlite is also good for your lawn