A white crust marring the earthy finish of your terra cotta pots is a indication of deeper problems than a unsightly blemish. Fertilizers include soluble salts that could build up in the soil of potted plants. Over time these incisions leach through the permeable surface of terra cotta pottery, leaving a white crust around the rim, drainage holes or side walls of the grass.
Salt Sources
Fast-acting chemical fertilizers provide nutrients to plants but leave behind water-soluble salts in the soil. Using a slow-release fluid limits the amount of salt in the grass by decreasing the frequency of fluid applications. Tap water in areas with soft water is another common source of salt in terra cotta pots, but typically it only adds modest amounts of salt unless implemented frequently in huge volumes. Using bottled or filtered water eliminates this source of salt.
Salty Sand
Terra cotta pots cradling plants at a sandy, fast-draining dirt are more prone to salt damage. Sandy soils make it possible for the nutrients that they contain to leach from the dirt and in the walls of terra cotta pots more readily. Potting mixtures having a reduced of concentration of sand can hold more nutrients and are less likely to leach salt to the walls of a terra cotta pot. Frequently applying light doses of fluid over a span of weeks adds salt to the soil more quickly than it drains out.
Problems With Salt
Excess levels of salt may harm plants if left unchecked; typical signals of plants suffering from excessive salt include wilting and yellowish or brown discolored leaf that does not perk up following the plant is watered. The first signs of a plant suffering from salt damage are wilting and discoloration during its leaf tips. The damage also goes to the roots; salt-damaged roots often appear dried and shriveled.
Washing Pots
Flushing the dirt with water every four to six months is the simplest way to remove salts and stop them from accumulating in the soil and washing to the walls of a terra cotta pot. The best method to flush the dirt with water would be to take the plant out and remove any catch tray so that water can drain freely. Water the soil steadily until the soil is saturated. Wait 15 minutes for the excess water to drain from the soil and then water it. Water the grass slowly to avoid developing a pool of water on the surface. Soaking terra cotta pots in a solution of 1 part vinegar and 3 parts water helps remove salty buildup.