Enhance Your Garden’s Growth with Viagrow 0.5 CU. FT. Coarse Vermiculite Viagrow 0.5 CU. FT. Vermiculite Coarse and Chunky Grade is a natural soil amendment that significantly enhances moisture retention and aeration in your potting mixes, delivering essential elements directly to your plant roots. This OMRI-certified vermiculite is a versatile addition to various growing media, whether you’re mixing it with peat moss, mushroom compost, cactus soil, or any other organic or soilless substrates. Viagrow Vermiculite #3 is designed to attract and hold positively charged ions, such as potassium, magnesium, calcium, and ammonium, slowly releasing these nutrients to promote vigorous root development, better growth rates, and higher yields.