Grodan A-OK 50/40 Rockwool 2" starter plugs 50 plugs (H6)

As a grower, the target is always to get good root distribution throughout the substrate slab. This is because good root distribution helps to make a more uniform and easier to control EC level and water content. An important factor influencing root distribution is the fibre structure: in a slab with vertical fibres, the roots grow down faster than they would in a slab with horizontal fibres. Maximising the number of hair roots growing in the substrate is also beneficial as they play an important role in nutrient uptake.