Firstly, a good propagation cube has to be solid and hold its shape. With these qualities both the cube and the plant will have the least risk of damage during propagation. This helps to guarantee a quality plant to the grower. The cube must also have good initial saturation and re-saturation during the propagation phase. A stone wool cube has to be fully wet up – during the initial saturation. The plug also needs to have good contact with the cube as this will influence the speed at which a seedling roots into the cube. This is where the density of the stone wool is important: the lower the density of the substrate, the easier the roots will grow into it.
During the propagation phase minimal variation between the water content in the cubes is very important. Any variation in water content will show more after delivery to the grower. So is vital that the cubes are fully wet up at the start. Any variation at this time will lead to a variation in water content and therefore plant growth.
High EC levels have a generative effect on the plant during propagation. Although high EC levels have no effect on EC refreshment, the EC in a Cultilene RootmaXX cube, where fibres run in every direction, this could well be the case in other cubes which usually have vertically fibres. The ‘X-fibre structure’ in a RootmaXX cube not only has a good effect on EC refreshment throughout the cube but also gives better EC distribution. The result? Better and more even rooting in the cube.