Grodan 36x36x40 mm planting cubes with hole and planter, 77 pieces in a BOX with 18 pieces. The Rockwool Grodan is an inert medium that provides optimal conditions for plant growth. It is made of basalt wool, has high absorption properties and promotes a balanced water/air ratio. This supports root development. Hole size: 6x15 mm, size of the planter with cubes: 53x32x4.5 cm.