Salt is a desiccant, or a drying substance. It removes moisture from substances it comes in contact with, such as the grass in your lawn. This drying property makes salt deadly to microorganisms that convert nitrogen into ammonia, which your grass needs to grow. When you pour table salt on grass, a dead spot forms where the salt fell.
Avoid salt damage by keeping all types of salt off your lawn. This includes salts used to de-ice walkways and driveways, though these cause less damage than table salt, according to the Department of Horticulture at Cornell University. Avoid commercial pesticides because, according to the University of California, they contain salt.
If you get salt on your lawn, you can undo the damage. First, remove as much as the salt as possible, by hand or using a broom and dustpan. Then, horticulturist Ron Smith of North Dakota State University suggests flooding the spot with water three times to dilute the salt.
Certain grass varieties are more tolerant to salt, and are less likely to die should you get it on your lawn. They include bermudagrass, tall fescue and Fults alkaligrass. Plant these if you're concerned about getting salt on your lawn.