Table salt is most commonly made out of sodium chloride. It is used for a variety of purposes such as preserving meat, adding flavor and melting ice. It is also found in large quantities in the ocean. Plants often adapt to the amount of salt in their environment over generations. When they are unexpectedly exposed to larger amounts of salt than usual, they can suffer ill effects and can even perish.
Salt found in deicers is sometimes splashed on to plants. This salt affects the cold hardiness of these plants and can make them vulnerable to frost. Snow filled with deicer salt is sometimes pushed into soil, which causes the salt to seep into the soil, harming plants. Salt can also end up in plants near coastal areas where there is a lot of seawater splashing up. Plants that are native to coastal areas have a high tolerance for salt, but other plants might not fare as well. Salt can also reach damaging levels when saltwater is used to water plants.
Plants need adequate amounts of water in order to hydrate themselves and absorb nutrients that they need. Salt absorbs a lot of water and can reduce the amount of water that is available to the plants. This can create situations where plants appear to be watered enough, but are actually deprived of water.
While sodium is good for plants in small amounts, too much sodium can be toxic for plants. In fact, according to Purdue University, salt is so toxic to plants in large quantities that it was used in warfare in order to kill the crops of enemies. The chlorine atoms that are separated from the sodium atoms and absorbed into the plant interfere with chlorophyll production, preventing plants from generating the energy that they need.
Some plants are good at controlling the amount of sodium that they absorb, while other plants can become overwhelmed. Some of these salt-loving plants are weeds that will show up and further sap nutrients from the soil, killing the intended plants, according to Purdue University.
While some plants start to wilt when they receive too much sodium chloride, other plants have symptoms that are hard to notice. Deciduous plants have a difficult time developing buds and leaves and can also develop a stunted appearance.
Calcium chloride acts as an effective deicer and does not harm plants as sodium chloride does. Coarse sand also can be used to increase traction on the snow, so the snow is not as slippery. Salt-tolerant plants also can be used to help plants survive heavy salt, since they are able to take up much of the salt out of the soil.