Using Rock Salt On Snow – Everything You Need to Know

Rock salt is used around the world to help prevent ice and snow from building up on roads and sidewalks. It’s fantastic for removing that bottom layer of snow that might be left behind from a snowblower for example. Rock salt benefits include:

  • work effectively in temperatures as low as -6 degrees
  • is easy to store
  • easy to distribute.

With so many types and brands of rock salt available, it can be tough to pick the right rock salt for your needs. With many questions to be answered, here’s everything you need to know about using rock salt on snow.

The Difference Between Rock Salt and Table Salt

While table salt and rock salt are the same things in terms of chemical structure, the form they take, and their uses differ greatly. The most apparent difference between table and rock alt is the size of the granules. Rock salt as significantly larger granules, making it much more effective when gritting a road, as it will dissolve at a lower rate.

Another major difference between rock and table salt is their additives. Table salt tends to contain more additives than rock salt and often includes iodine to help prevent iodine deficiencies when consumed. Rock salt generally has more anti-caking agents, so it doesn’t stick together when sat in a bag for a long time, making it easier to spread. While rock salt is safe to consume, it’s best used for its intended purpose, gritting roads.

The Best Rock Salt For Snow

As mentioned, there’s a plethora of brands and types of rock salt on the market, making it hard to choose the best rock salt for you. The most reliable place to purchase rock salt is from your local home improvement store, as they can help you pick the best rock salt for your requirements. If you can’t make it to your local store, several online retailers offer the same products.

One of the most popular rock salt brands in the U.S. is Morton’s Safe-T-Salt. This rock salt is relatively inexpensive and melts snow at temperatures as low as five degrees Fahrenheit. This rock salt is also useful when cars are stuck in snowdrifts, providing excellent traction for tires. 

If you’re looking to spare no expense when gritting your road, sidewalk, and driveway, look into purchasing Green Gobbler Pet Safe Ice Melt Fast-Acting Treatment.

This rock salt costs over twice as much as Morton’s Safe-T-Salt but will melt snow at temperatures as low as -10 degrees Fahrenheit, ensuring you’re prepared for even the most frigid blizzard. This brand’s pellets contain magnesium chloride, an extract of sea salt.

This type of salt is safer for the environment and won’t harm or irritate your pet on contact. At the same time, magnesium chloride is less likely to damage your driveway and cause spalling, which could put you out of pocket. It’s also better for the environment and won’t cause damage to your drive. In some ways, calcium chloride is more effective than magnesium chloride, as it causes an exothermic reaction, which warms the surrounding snow helping it melt quicker and more efficiently. 

Regardless of what brand of rock salt you buy, you’ll always want to see which one has the highest concentration of pure salt. Purity is essential because the higher the level of salt, the lower temperature it will work at, and the better it will be at creating traction. Marine salts like magnesium chloride usually have a purity of 99.9% and tend to dissolve quickly while not leaving behind any grit once the snow is gone.

It also doesn’t stain like normal sodium chloride does, which is important in case you spill some on your clothes or carpet. All types of rock salt are hygroscopic, meaning they absorb water particles in the near vicinity, allowing them to work even faster. Meanwhile, Calcium chloride works at an even lower temperature than magnesium chloride and creates an exothermic reaction. 

Overall, the best type of rock salt to buy is one containing calcium chloride, which works at the lowest temperature. Like magnesium chloride and sodium chloride, calcium chloride absorbs nearby moisture and creates an exothermic reaction.

These factors mean it’s effective at the lowest possible temperature and works the quickest, making sure you can get back on the road in no time.

What Temperature Does Rock Salt Become Ineffective?

One critical factor in applying rock salt is knowing what temperature it stops working. In general, your standard sodium chloride-based rock salt will help create traction at temperatures as low as -6 degrees. However, most halite rock salts stop efficiently melting ice at a much higher temperature. Your run-of-the-mill rock salt will stop melting ice at 15 degrees, as it’s unable to break down water molecules in such icy conditions. 

When attempting to melt ice and snow at temperatures below 15 degrees, you’re best off buying a calcium chloride or a high concentration magnesium chloride-based de-icer. As discussed, these rock salts work at much lower temperatures than sodium chloride (calcium chloride as low as -25 degrees).

How To Apply Rock Salt Effectively and Efficiently

Another crucial factor is knowing the best way to apply rock salt to your driveway, road, or sidewalk. If you know there’s snow heading your way, the best thing to do is to spread your rock salt out before the snow begins to fall. This way, you can get a head start on melting the snow and avoid any potential injury from slipping over while applying your rock salt in frosty conditions.

It’s also imperative you keep an eye on the temperature to make sure you’re not applying rock salt unnecessarily. Halite rock salts stop working around 15 degrees, and cold northern winters regularly dip below this temperature. If you only have standard rock salt and you’re looking to create traction, a great cheap alternative is cat litter.

If snow is falling thick and fast, you may want to use a different tool to clear your driveway. Rock salt only works on thin layers of snow and is unlikely to melt compact coverings. You may want to use a shovel or snow blower to remove the majority of snow before applying rock salt to soak up the rest.

You can also apply rock salt to densely packed snow to help break it up, making it simpler to remove with a shovel. You’ll want to make sure you disperse your rock salt evenly, so it doesn’t end up all in one place. If you’re spreading your fertilizer by hand, one of the simplest ways to make sure you get an even coating is by shaking out of a cup or tin can. The best method for sowing rock salt is with a spreader. Spreaders make sure you get an even distribution while giving you better control than using a shovel or cup.

You’ll find spreaders less labor-intensive, too, which is perfect for anyone suffering from back pain or chronic injury. If you don’t have a purpose-built spreader, you can also use a fertilizer spreader. Most fertilizer spreaders have an adjustable chute, which can accommodate most rock salt pellets.

It’s worth noting that using more rock salt doesn’t mean it’ll melt more snow, and it’s best to use a thin, even coating. You should use about four pounds of rock salt per 1,000 square feet. If you have any salt leftover after the snow has melted, the chances are you’ve used too much. 

Top Tips For Using Rock Salt Safely

Rock salt of all kinds can be harmful to the environment, potentially seeping into nearby rivers, lakes, and swamps, damaging your local ecosystem. Even a small amount of rock salt can cause a lot of destruction, so make sure you clean up and dispose of any rock salt left behind.

Rock salt can also be harmful to pets. While most magnesium chloride and calcium chloride-based rock salts won’t irritate your pet’s skin, all rock salts are toxic to animals if ingested. If your pet ingests rock salt, they could suffer from vomiting, disorientation, fatigue, and even salt poisoning. 

Ensure you take safety precautions when handling rock salt by wearing gloves, as it can cause skin and eye irritation. The best way to dispose of your rock salt waste is by transferring it into a sealable plastic container, and then taking it to a nearby waste management center. 

Suitable Surfaces For Rock Salt

While rock salt is superb for removing snow and ice, there are few things to keep in mind before using it on certain surfaces. Sodium chloride-based rock salts are inexpensive but can cause potholes and spalling in on sidewalks, driveways, and roads. All types of rock salt will usually leave a salt residue if used frequently, even on asphalt, wood, gravel, and tiling. 

There are a few surfaces you’ll want to avoid entirely when applying rock salt. Metal is subject to salt corrosion when exposed to salt and water, causing rust and ruining the metal’s finish and integrity. As a result, you should move your vehicle out of the way while applying de-icer to your driveway, as salt will corrode your vehicle’s metal parts, wrecking it’s finish. 

At the same time, you’ll want to avoid applying rock salt to your lawn or garden. High concentration rock salts are toxic to most plants and will kill flowers and grass. Rock salt will ruin your garden, so it’s best to avoid applying it anywhere except on asphalt, gravel, and concrete. Over time, rock salt will cause some damage to most surfaces if applied often and is best used sparingly.

What Can I Do With Rock Salt At The End Of The Winter Season?

You may find yourself with a lot of rock salt left over when the winter ends. Thankfully as salt is a mineral, it won’t spoil as long as you store it in a sealed container and a dry place. You can also sweep up and store salt left behind on your driveway, which will save you buying more salt the following year. 

Unfortunately, there aren’t many ways of using rock salt other than for removing snow. You shouldn’t use rock salt as a weed killer, as it will damage any other nearby plants and ruin the soil for the foreseeable future. You also shouldn’t use rock salt as a water softener. While it’s cheaper than water softener salt, rock salt tends to have significantly lower purity levels and contains insoluble materials that can clog your pipes.

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