What is water holding capacity?

The Water Holding Capacity is the amount of water that a medium can hold. This is affected by the media composition, texture, plant roots, any rocks or similar and, in the case of pots, slabs or bags, the size and shape of the container.

The Maximum Water Holding Capacity, also known as the Field or Pot Capacity, is the maximum amount of water that specific pot/bag/slab/similar can hold without it draining out.