Terra cotta and earthenware are always slightly porous. Although this allows plant roots to breathe, it also constitutes a risk in winter. When the temperature drops below freezing, any water present in the pot walls will freeze and expand. This will cause the pot walls to spall and can ultimately destroy the pot. Since Campanias terra cotta is hand-made, they absorb far less water because the clay is processed differently. They are frost-resistant if handled correctly. However, because any water held in a pot from rain or melting snow will freeze and expand, any pot made of a non-elastic material is at risk if left outside left unprotected during winter. Although Campanias planters are of high quality and are frost-resistant it is still recommended that they be stored in a frost-free covered area in winter. If left out, water may accumulate in the container and freeze, casing the planter to crack and break. '