Containers with bottom holes which drain excess water are vital for the health of Haworthias. Regarding the volume, a good container should have some room for the roots to elongate otherwise the plant growth may stunt. Besides, for a stable water evaporation, the top of the container should be large enough to make a part of the growing medium not covered by the plant. Certain Haworthia species like H. truncata have deep roots and generally fit better in deep containers.
A container made of a porous material (for example, unglazed clay-based ceramics) is air permeable and evaporates a large amount of water through the sides. This causes the root tips reaching the sides to be desiccated, and inhibits the root growth nearby. It is generally recommended to use containers made of non-porous materials (for example, plastic or glazed ceramics).