Lightweight flakes that increase the retention of water & nutrients. Use on its own or mix 50/50 with compost for seed germination Vitax Vermiculite is a natural mineral that has been heated to high temperatures to produce lightweight, highly absorbent flakes. Its use in the garden will improve the aeration of growing media such as compost or soil & increase retention of moisture & nutrients. It will also help to promote faster, healthier plant growth.