Midwest Hearth extra coarse perlite can be used to create a soil mix for indoor planting or hydroponics. The large surface area of the perlite particles is covered with tiny crevices that retain nutrients and moisture that your plants can use as needed. Perlite's capillary action and more neutral pH make it better for hydroponics. It helps plant roots breathe and is a light weight substitute for sand. When mixing your potting soil, make sure it contains at least 25 percent perlite for optimal drainage purposes.