Now that it is winter and snow is starting to invade many regions of the country, municipalities are prepared to spread ice melt or rock salt on the street to inhibit
the formation of ice. In addition, you may use some kind of ice melting product on your home’s cement walkways or on the surface of your carport or the area leading into your garage.
You are probably aware that rock salt can damage your lawn. Commonly used ice melt products that are used include rock salt (sodium chloride), potassium chloride, magnesium chloride, calcium chloride and urea.
You may not be aware of it when the substance lands on the grass during the winter, but the results will be evident when you see brown grass after the snow and ice have left and the nice warm spring environment encourages your grass out of its dormant state and begins to grow again.
The damage to the lawn is caused by a number of elements of the ice melt. First, ice melt products that have salt remove moisture from the soil and prevent it from getting to the roots of the grass. The grass plants dehydrate and ultimately die. In addition, particles of the ice melt can leach the moisture from the grass blade causing it to brown and wither. Getting ice melt on dormant grass blades may not do a lot of damage, but it will prevent the grass from getting the water it needs to grow when the warmer weather arrives.
Second, ice melt that includes salt includes toxics. The toxics are released when the salt separates into its basic ions when dissolved by water. The sodium ions block the roots of the grass from obtaining needed nutrients including calcium, potassium and magnesium. The chloride ions are absorbed into the roots and can grow to toxic levels. When grass has too much chloride it can’t produce chlorophyll and the blades starve causing them to be unable to convert sunlight into energy.
Although it is true that small amounts of salt in the soil will not present a problem, the amounts can build up over time and stay in the soil. It can accumulate every year until the salt ultimately creates a toxic environment for the grass. Salt stays in the soil until it is washed away. This means that you won’t be able to plant new grass until the salt is eliminated. You don’t have to wait for Mother Nature to produce a rainstorm. You can thoroughly water the infected area yourself to rid the soil of the salt. Deeply soak the lawn every day as soon as the weather turns warm so that the salt will drain below the root level of the grass.
You can place temporary snow or silt fencing along your lawn near the street to protect it from the ice melt spread on the street. You can also cover the area with plastic sheeting and place rocks or landscape staples on it to keep in place.
Use sand or kitty litter instead of ice melt on the walkway and driveway or consult with a representative at your local garden center to see if he or she can recommend an ice melt that is safe for landscape use.
Wait for spring so the grass can turn green to determine the damage.
It is possible that you will not have to do any repair work. Melting snow and rain common in the spring will often wash away the accumulated salt from the soil. It may take as long as six to eight weeks for the lawn to heal itself.
If for some reason rain is sparse, then watering the damaged area three or four times should remove the salt.
However, if damage remains, then you will have to reseed the area.
Before reseeding use a rake to remove the dead grass. You may also have to use a rake or shovel to loosen the top ¼ to ½ – inch of soil to create a good seedbed. You can use a product that combines seed, mulch and fertilizer on the infected areas. Follow the product’s instructions when spreading it and water regularly until the seed gets established. Expect recovery to take two to four weeks depending on temperatures. The cooler the temperature, the more time it will take for the seed to germinate. It will take another six to eight weeks more for the seed to become well established.
Do not spread pre-emergent herbicide on the damage area before you seed. Although it will prevent crab grass, it will also prevent the seed from germinating. Wait until the new grass has grown to a height equal to the existing grass and mow two to three times before using herbicide to control the crabgrass on the area.