Grodan Propagation Cubes are perfect for both seedlings and cuttings. Suitable for most hydroponic systems (they can also be used in soil), these rockwool cubes are sterile and lightweight. They contain no nutritional value and therefore allow you to control the amount of feed given to young plants. It is recommended that you soak these cubes in a PH adjusted solution before planting seeds or cuttings. Available in two sizes, these cubes come supplied with trays in quantities of 24/77 (large cubes) or 48/150 (small cubes).