Salt gets on grass in many ways. In the winter, road salt that is used to melt snow and ice can get into your yard. If you live near the ocean, the salt comes with the spray. Sometimes pools have salt in them and get salt on the grass when they are drained. However, it gets there, here is what you need to know about its effects on turfgrass.
Does Salt Water Kill Grass?
Yes, it does. Salt water will kill your turfgrass if enough gets on the plants. There are some turfgrasses that are less sensitive to salt, such as St. Augustine, Bermuda grass, and zoysia grass, but even they will die if they get too much salt water on them.
What Is Salt Water?
There are many types of mineral salts. The most common is sodium chloride, or table salt. We, and every living creature, require a certain amount of sodium chloride to live. However, too much sodium chloride causes problems.
What Does Salt Water Do To Grass?
Will salt kill your weeds and grass? Yes, and it does so very effectively. Here is how that happens.
- Salt burns the grass blades like an overdose of fertilizer does. These burns form scars, and they lack chlorophyll. If enough of the grass blades get burned, they cannot make energy to sustain the plant.
- Salt dehydrates the grass. When there is more salt in the soil than in the grass, the salt draws the water out of the grass. Without water, the grass cannot transport nutrients or do the cell maintenance it needs to do and that kills it.
- Grass can die from sodium (Na) toxicity. The sodium and chloride ions separate in water and each causes problems. The chloride ion goes to the roots and enters the grass there, then goes to the grass blades and hampers photosynthesis. The sodium ion causes sodium toxicity in the plant. In addition, the sodium displaces other mineral salts and the grass cannot get the nutrients it needs to live.
- The sodium disperses fine soil particles and clogs the pathways that water and nutrients use to penetrate the ground. This destroys the soil structure and plants cannot survive.
Related Article: What Kills Grass? The Comprehensive List
Why Doesn’t Salt Water Kill Your Grass? (If you were using it intentionally)
It takes about two weeks for the effects of salt water to become apparent in your turfgrass. Be patient, it will work. If it doesn’t, the salt concentration in the water was not high enough.
What to Use Instead Of Salt Water to Kill Your Grass
While salt water will kill your grass, it kills everything else in the soil, too. Microbes that are necessary for plants to uptake soil nutrients die, earthworms and other invertebrates in the soil die, and the soil collapses. It is better to use an over-the-counter herbicide to control grass and weeds. Products using 2,4, D will work for narrow leaf grass, but will also kill broadleaf grass such as St. Augustine. If you want to kill all the grass and weeds, use a product with glyphosate in it. Be sure to follow the label so grass and weeds are all you kill.
Does Salt Water Kill Soil Microbes?
Yes, salt water will kill soil microbes. The soil microbes are important to all plants. They help make the nutrients in the soil accessible. The salt water dries them out and changes the soil chemistry, killing the microbes. In the past, when armies destroyed a rebellious town, they would burn it down and salt the earth. That kept anything from growing there for a long, long time.
Will Salt Pool Water Kill Grass?
Yes. Salt water pools generally have 3,000 ppm salinity. To achieve that, you have to add 25 lbs. of salt per 1,000 gallons of water. Even if you drain a small 2,000-gallon pool in your yard, that is still 50 lbs. of salt. That is more than enough to kill your grass.
How Do I Treat Salt Water Spills On Grass?
Treating salt water spills takes several steps. If the salt water spill is mild, flushing the landscape where it occurred with six inches of water, delivered an inch a day, will remove 50%-70% of the sodium out of the soil. Make sure the drainage from flushing the turfgrass does not just poison another patch of your lawn. Flushing in this way works better on sandy soil than on clay soil.
If you have clay soil, you will need to aerate the turfgrass with a plug aerator to open up the soil and provide more area for water to reach the root zone. You will then need to apply gypsum (calcium sulfate) at a rate of 50 pounds of granular gypsum per 1000 square feet once a month. Water the gypsum in with an inch of water. Take a soil sample from the area once a month before the gypsum application. Continue the gypsum monthly until the soil salinity on the soil sample is back to a safe level. Gypsum displaces the sodium from the soil particles, so it is flushed out of the root zone easier. Do not use gypsum for a small spill on sandy soil.
In conclusion, salt water will kill grass and weeds. In fact, it will kill everything in the area it is applied and will damage the soil structure. Because salt water is so destructive, it is better to use an appropriate herbicide to kill weeds and grass. If you have a salt water spill, flush sandy soil. For clay soil, you will need to aerate the grass, apply gypsum, and water the gypsum in monthly until the soil salinity is back to normal. It is much easier to avoid getting salt water on your grass in the first place.