Terracotta is red-firing earthenware clay, coloured by iron, fired at low temperatures and often left unglazed. The name is Italian for baked earth, and it is used for garden pots, tiles, sculpture and rustic tableware.
What Is Terracotta?
Terracotta gets its warm orange-red colour from iron oxide in the clay. It is usually fired around cone 06 to 04, where it stays porous, which is why unglazed terracotta pots let plant roots breathe and water evaporate through the walls.
It is one of the easiest clays to work: soft, smooth and plastic, and it can be burnished to a sheen or decorated with white slip for strong contrast. Many sculptors and tile makers favour it for its colour and ease.
For tableware, terracotta needs a well-fitted glaze covering every surface that touches food, and the glaze should be rated by its maker for food use. Unglazed or crazed terracotta absorbs water and can harbour bacteria. Fired too hot, red earthenware can bloat, blister or melt, so it must stay in low-fire loads.
Terracotta also describes the colour, and the word is used loosely for many red clays, so check the cone on the bag before you buy.
This pottery glossary entry from Le Studio Art Space is general educational content. Always follow the clay, glaze and kiln makers’ data for your own materials and equipment.