Grodan Rockwool Cubes with Holes - 6 x 6 x 6 Inches - 4 Pack
Rockwool is an inorganic and sterile growing medium made from spun molten rock. A superior medium for rooting cuttings, rockwool provides 20 percent air space when saturated, and does not contain nutrients. It is recommended that rockwool be conditioned by soaking for eight hours in a pH 5.0 - 5.5 and then rinsing with pH 7.0 water. Water daily.