Vermiculite Medium Grade Bag 12 Quarts If you are growing an organic crop and looking for an OMRI listed and CDFA product that will provide maximum yield, then look no further. Our Horticultural Organic Vermiculite will keep the soil from clumping, making it easier for roots to develop. Benefits Excellent buffering for the root zone Holds moisture and nutrients for later use Supplies the roots with plenty of oxygen so growing plants are stronger, healthier, and have higher yields Clean, odorless, non-toxic, and completely sterile–no bacterial or fungal infections to worry about For Small Gardens and Hydroponics Horticultural Vermiculite is a valuable growing medium for small area gardening and hydroponics. A mix of one part vermiculite, one part compost, and one part peat moss makes an ideal blend for small-area gardening, providing maximum growth. A 50/50 mix of vermiculite and perlite is a popular medium for drip hydroponic and ebb-and-flow systems. Mixed with natural soil, peat, organic compost, or bark, it will hold moisture, retain air, and provide plant food with a minimal amount of water required.