Clay pots make great planters because they allow the root system of the plants to breathe and make it hard to overwater them. However, these pots will crack and break if dropped, or if they are allowed to freeze, particularly if they are damp when the weather turns cold. A broken pot does not need to be thrown out. It can be fixed with a little effort and will work just as well as before.
Remove any dirt by first brushing it off and then washing the pot with soap and water. Rinse the pot and let it air dry thoroughly.
Open the crack slightly with a wedge if necessary and apply a thin layer of silicone caulk throughout the entire crack. Remove the wedge.
Wrap the pot with a piece of wire to squeeze the crack together and secure the ends of the wire by wrapping them around each other. Allow the silicone to dry. The time varies depending on the manufacturer, but overnight will work well. Remove the wire and check the crack. Peel any excess silicone away.