Brush away any dirt or chips of terra-cotta from the broken pieces with a dry paintbrush.
Wipe down pieces with a damp rag and allow to dry.
Seal the broken edges with a solution of water and Weldbond glue. Mix 1 part Weldbold and 5 parts water in an empty tin can. Apply a thick coat to broken edges with a disposable paint brush and allow to dry thoroughly.
Spread a thin layer of full-strength Weldbond glue on both broken edges. Place pieces back together and clamp gently. Apply enough pressure to hold the pieces together but not enough to crush the terra-cotta. You may wish to pad clamps with rags where they contact the terra-cotta.
Allow glue to dry for at least 24 hours. If glue is not clear, it is not dry yet.
Remove clamps from bowl.