Therm O Rock 100055151 Vermiculite 2 Coarse 2cuft, 2 cu. ft, Brown/A Therm-O-Rock Vermiculite 2 Coarse 2cuft Therm-O-Rock's lightweight vermiculite provides superb aeration, as well as moisture and nutrient retention when mixed with peat, bark, or compost It is excellent for seed germination, prevents soil compaction and promotes strong and fast root development Coarse vermiculite can be used to mix with peat and compost for raised vegetable beds