Clay also has the tendency to form a white crusty layer on the outside of the pot. This is formed when mineral salts dissolved in the water are wicked from the potting medium into and through the pot wall. Some find this layer attractive, most gardeners find it unsightly. The salt deposits can be scrubbed off if their appearance offends. A final disadvantage, clay is easily broken.
Plastic pots are lightweight, strong and flexible.
They are available in every color of the rainbow to coordinate with interior and exterior decor. Plastic does not have the wicking action that clay has making them an excellent choice for moisture-loving plants or for those gardeners who water infrequently. Plastic pots are made of inert materials and are considered safe for growing plants. Plastic pots generally have thinner walls than their clay counterparts offering roots little if any insulation from temperature change. Black plastic can actually act as a solar collector, heating up the potting medium to plant damaging levels.