Planter Boxes

On Slab Medias are the growing media used on an artificial base rather than on the ground or in large containers with restricted root area.

They are different to potting mixes in that they are usually a mineral and organic blend with a bulk density of between 0.3kg/litre and 0.8kg/ litre. They tend to be used for larger volumes and have a longer life span than potting mix.

When designing an on slab media for planter boxes it will have similar requirements to potting mixes in that it requires superior water holding capacity and air filled porosity. This ensures good root development and sustained growth.

On Slab Media is applied in the top 300mmm deep of the planter as the growing media around the root zone. Under this the remaining depth is filled with coarse river sand to ensure subsoil oxygen is adequate and to avoid anaerobic conditions forming.

Product Information Where to Buy



  • Planter boxes
  • Raised garden beds
  • Areas where increased drainage or permeability is required.