Clay pots are available in many designs and sizes. These containers are mostly used for housing plants. They're made of terra-cotta, which is baked earth clay. They've also been used as containers for sculpture, bricks and roof tiles in Eastern and Western cultures, notes the Demesne website. Just as any type of pottery, the quality of clay determines the quality of the finished pot.
Clay pots serve as a healthy environment for most potted plants, notes the University of Nebraska-Lincoln Extension. Because clay is porous, moisture and air penetrate the sides of a pot. The fine roots on the edges of soil balls use this moisture and air. Clay pots act as wicks because they get rid of excess moisture in potting soil.
Sizes of clay pots include regular-shaped pots, modest-sized containers and azalea pots, according to the Clay Flower Pots website. A plant's size and its roots determine the size of pot to use. For example, rose plants have deep roots, so they need a pot that's large enough to accommodate longer roots. Azalea clay pots, which are shorter than a regular clay pot, are intended for azaleas and are more broad than tall.
The most common clay pots are hand-turned and molded. Made individually by potters, hand-turned pots come in many sizes and shapes. Molded pots are mass-produced in factories where the clay is fired at different temperatures. Molded clay pots aren't usually frost-proof, Demesne notes.
Clay pots should be thoroughly cleaned to prevent crusty residue caused by salts from fertilizers. When salts contained in fertilizers dissolve in water, they move through clay. This causes a crusty residue to develop on a the surface when a pot dries. A main sign of salt toxicity is a browning on edges of foliage. The Alabama Cooperative Extension System recommends soaking pots in a solution of 1 cup of vinegar mixed with 3 cups of water.
Clay pots can harbor diseases, the Alabama Cooperative Extension System warns. When pots are stored during winter, disease organisms stay dormant. These organisms, however, revive when pots are used. Soak pots overnight in a bleach solution to kill any organisms that could cause damage. Use a solution of 1 cup of bleach for each gallon of water.