Grodan rockwool is an excellent quality stonewool sub-
strate 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.

Rockwool blocks containing plants are set on top of the
slabs and the roots grow through the block and into the
slabs. Nutrient solution may be applied through a spray
or drip emitter either directly to the slab or through the
growing blocks. Blocks are commonly used for germin-
ation of seed and rooting cuttings. The vertically oriented
fibers in blocks promote good downward root growth.