Can Salt Hurt Your Lawn?

Types of Salt

• Sodium chloride is the salt used for cooking and flavoring. It does not take much table salt to harm a lawn. Other salts that are helpful to lawns in small amounts are known as fertilizers and include potassium chloride, ammonium nitrate, concentrated super phosphate, magnesium sulfate, calcium nitrate and potassium nitrate. These contain important elements that are vital to plant growth.

How Harm Occurs

• Plants depend on a delicate balance of moisture in the soil and the ability of the plant roots to draw the water into the plants and then transport nutrients around the plant. If the balance is upset by applying too much fertilizer, the plants suffer harm. Salts are hygroscopic, meaning that they draw water to themselves. If there is an excess of salt in the soil, the water is drawn out of the grass roots, which then deprives the plants of nutrients. The grass becomes brown and appears dry, which is why the condition is called "burned."

Dog Urine

• This burned condition is seen often on lawns where dogs are allowed to urinate. Urea salts in the urine are an immediately available source of nitrogen to the plant roots. When the dog has minimal urea salts in the urine, the grass in those spots he relieves himself will be greener and more vigorous than other parts of the lawn. However, if the dog has a greater amount of urea salts than the plants can tolerate, the lawn will have circles of grass that appear dead.

Mitigating Harmful Salt

• The only solution to excessive salt in a lawn is to leach it out by pouring water through the soil. Salt is water soluble, and as the water flows past it picks up the salt and takes it with it. Running the sprinklers for several hours per day over several days might be sufficient to minimize the damage and allow the lawn to spring back. If the grass is permanently harmed, then starting over with a new lawn may have to be done.

Salt-Tolerant Grass

• As grass evolved, those plants by the ocean coastal areas grew more salt tolerant. This enabled them to survive soil conditions that would kill other plants. Zoysia and Bermuda grass are both highly adapted to salty conditions, but both need good amounts of sunshine. St. Augustine grass is a better choice for shady areas even though its salt tolerance is not as high. Even the most salt-tolerant grass can be harmed if the salt level is too excessive.