Grodan Grow Cubes are know thought the industry as croutons, these Grow Cubes are lightweight and much cleaner than peat or coco based media. Grow Cubes (1/2") are easily mixed with other looses media(i.e clay rocks). They provide excellent aeration and optimum drainage(minimizing damage of user overwatering).Grow Cubes are very popular in various brands of fabric pots and bucket systems.