Perlite is a mineral which is super-heated and pops like popcorn. These lightweight particles increases aeration and decreases water-holding when incorporated into soil. It is clean, odorless, non toxic and sterile. Light weight and easy to handle it mixes with potting mix or soil. Mixed with peat, perlite promotes drainage and air capacity. Mix with your potting mix when planting seeds so young roots can move more easily. Helps roots to breath.