Grodan Rockwool 36/40 Sheet of 98 Cubes 1 in. x 1 in.

Grodan rockwool is an excellent quality stonewool substrate with a very high water holding capacity. Rockwool is absolutely free of disease, salts, and weed seeds. It has no Cation Exchange Capacity (CEC) so the grower can take advantage of a nutritional program specifically tailored to the crop being grown.