Calcium chloride is used for two things in lawn and garden care. First, it can be used to add calcium to the soil in a ready-to-absorb format with few drawbacks. Second, calcium chloride is frequently used as an ice-melting product, in both pellet and powder forms. While the former use is specifically formulated to benefit grass, how much calcium chloride can be applied before it’s too much? Will calcium chloride kill grass in the concentrations found in ice melting products?
Will Calcium Chloride Kill Grass?
No, calcium chloride should not kill grass if it is applied responsibly. For many people, calcium chloride is a necessary substance when winter rolls around. It is the only widely available ice melting product that works down to -25 degrees Fahrenheit. Calcium chloride will only damage grass, plants, or other living creatures when over-applied.
What Will Calcium Chloride Do to a Lawn?
Calcium chloride breaks down into calcium and chloride when it is mixed with water. It has about half the sodium content of sodium chloride (rock salt), another popular ice melting substance.
A reasonable amount of calcium chloride sprayed on a lawn will provide a quick boost in calcium to nearby plants, including turfgrasses. This boost in calcium can help grasses grow straighter, develop greater tolerance to insects, and hold up better after being mown.
Related Article: What Kills Grass? A Complete List of Dangers
What Does Calcium Chloride Do to Lawn Soil?
Calcium chloride is highly water-soluble and should not cause any change in pH or build-up of unwanted substances in the soil if used responsibly. What it will do is provide a small amount of calcium, sodium, and chlorides. These substances are all used by many plants, including grasses, in small amounts.
If applied in large doses or regularly over many weeks or months, calcium chloride may lead to the build-up of all of these substances, the most harmful of which is sodium. Sodium levels that are too high can disrupt plant growth, leading to the death of grasses and other plants from the root up. Plants may appear “burnt” or take on a yellow hue.
If calcium chloride is liberally applied to driveways, sidewalks, and walkways during the winter and snowfall is insufficient, nearby grass and plants may die from the build-up in sodium. The best way to prevent this is to only use as much calcium chloride as necessary and then dilute the runoff with water as soon as the ground begins to thaw in the spring.
Does Calcium Chloride Kill Grass and Weeds?
Yes, calcium chloride can harm grass and weeds to the point of killing them if overapplied. This over-application is difficult to do by accident unless the ground is already wet and a pail of dry calcium chloride pellets has been spilled onto it.
In cases like these, the sodium content in the calcium chloride will make short work of any plant life it has touched while building up in the top layer of soil. This will further prevent any seed germination or plant growth until the sodium content in the soil is sufficiently diluted. Chlorides can also slow root growth, burn plants, and disrupt nutrient absorption in these high quantities.
How Much is Too Much Sodium Chloride?
This is one of those “your mileage may vary” types of questions. How much calcium chloride is too much depends on how much snow and ice it is being used to remove and whether the calcium chloride product you use is mixed with any other products.
All de-icers should be used to soften ice so it is easy to remove manually. They should not be applied in such quantities that they completely prevent ice from forming in the future. If this is the situation you have, too much de-icer has already been applied.
The only way to stay safe when using any de-icing product, including calcium chloride, is to start with a very sparse sprinkle of the product and wait to see if more is needed. It can take time to get a feel for what is right in your area and at what temperatures, but this is the only way to safely apply calcium chloride and spare your lawn from stress.
Calcium Chloride Is a Safer De-Icer Than Rock Salt
Though not without faults, calcium chloride is much safer for lawns, decorative plants, and pets than sodium chloride and is as just as widely available. Though calcium chloride does have a similar potential to build up in the soil or create runoff that is too nutritionally dense for most plants to process, it is less likely to do so with normal use.
Calcium chloride is also a much faster working and widely effective form of ice and snow control, meaning even less may need to be used than rock salt to produce the same effect. All of this adds up to make calcium chloride the better choice if you want a healthy lawn once the winter is over.
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