Vermiculite is growing medium that Improves aeration of the soil, promotes a consistent release of added fertilizer and improves moisture retention of the soil. It is very lightweight and mixes easily with other mediums. Vermiculite added to the garden or vermiculite in potting soil increases water and nutrient retention and aerates the soil, resulting in healthier plants. Vermiculite is far superior for water retention. Vermiculite, although less aerating than perlite, is the amendment of choice for water-loving plants.