Why are my terracotta pots grey on the inside?

Terracotta pots can turn grey on the inside due to a buildup of minerals, salts, and algae from water and soil. When water evaporates, it can leave behind these residues, leading to discoloration. Additionally, if the pots are exposed to high humidity or moisture, it can promote the growth of mold or mildew, contributing to the grey appearance. Regular cleaning and ensuring proper drainage can help prevent this issue.