Rockwool Hugo block, 6 inch cube. 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.
The
vertically oriented fibers in blocks promote good downward root growth.