The Effects of Salt Water on Plants

Most living things, including plants, need a little salt to carry out chemical processes. Too much salt, however, can have negative results on the plant's appearance, growth and hydration.

Osmosis

All plant cells have permeable membranes. This means that molecules can pass in and out of the cell. If there are a large number of water molecules in the cell, the cell is said to have a high water molecule concentration. Because of how electrons are exchanged from the molecules, water molecules move from areas of high concentration to areas of low concentration to neutralize the concentration difference. This process is called osmosis. In plants, cells take in water when there are more water molecules on the outside of the cell than there are on the inside.

Dehydration

Because of how osmosis works, when salt water is introduced to a plant, water wants to move out of the plant cell into the area that has fewer water molecules. The result is that the cells become dehydrated and cannot function properly. This means that the plant can show signs of drought (wilting, yellowing or browning of leaves, stunted growth) even if the plant is watered regularly.

Stunted Growth and Production

When plants are watered with salty water, they end up having to fight the osmosis process. They expend much more energy than normal, and because they cannot put their energy into flowering or making leaves, they may not grow as much or produce as well.

Nutrition

Salt water affects the ability of a plant to take up essential nutrients. This causes nutritional imbalances in the plant, which may stunt the plant's growth or cause yellowing of the leaves.

Considerations

Not all plants have the same tolerance for salt. Some can handle water that is saltier, while others are sensitive. Additionally, plants are more sensitive to salt at particular times. In hotter weather, for instance, when water needs are great, high salinity becomes more of a problem. Immature plants also are more sensitive to salt than mature plants.

Salt Sources and Remedies

Some people live in areas where the concentration of salt in the water is high. There is little to be done in this situation except to water the plants with purified water. Another source of salt water that can be overlooked is home water softening systems--avoid using tap water to water your plants if you have one of these systems, since salt is used in the water softening process.

References

• Osmosis
• How Does Salt Water Affect Plants on Land?
• Soil Salinity