The Vermiculite Medium 4 Cu Ft is a horticultural soil amendment made from expanded, heat-processed mineral material. ItA is commonly used to improve soil aeration while also increasing moisture retention, helping roots access both air and water more evenly. Its lightweight, sterile, and pH-neutral properties make it well suited for seed starting, propagation, and greenhouse growing mixes. This product is frequently blended with peat moss, compost, bark, or potting soil to create custom growing media for vegetables, ornamentals, and container plants.