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Salt Injury To Plants: How To Save Plants From Salt Damage

Salt Injury To Plants: How To Save Plants From Salt Damage


By: Susan Patterson, Master Gardener

In northernmost regions where the use of salt spray is popular during winter, it is not uncommon to find salt damage on lawns or even some salt injury to plants. So how can you reverse salt damage once this happens? Keep reading to learn more about treating salt damage to lawn areas and how to save plants from salt damage.

Salt Damage on Lawns

Anyone living in the North along a busy roadway where salt is used to help melt ice understands how damaging salt is to lawns. The salt draws moisture from the grass and causes it to brown.

Salt used to de-ice roads is mostly refined rock salt, which is 98.5 percent sodium chloride. Calcium chloride is less damaging to lawns and plants but is not used as often as refined rock salt because it is more expensive.

Treating Salt Damage to Lawn

Use pelletized gypsum soil condition to reverse salt damage on lawns. The gypsum, or calcium sulfate, replaces the salt with calcium and sulfur, which will help to heal the grass and encourage new growth. It is also useful in helping the soil retain water.

Use a lawn spreader to spread a thin layer over the affected grass and water well. Minimize your use of salt on walkways and driveways and try putting up a burlap screen or snow fence along the road to keep salt damage on lawns to a minimum.

Salt Injury to Plants

Much to many homeowners dismay, wind driven salt spray from road trucks can travel up to 150 feet. This salt can cause extreme damage and salt injury to plants as well, especially pine spruce and fir.

Salt damage to evergreen plants causes needles to turn brown from the tip to the base. Deciduous plants may be damaged, but this will not be noticeable until the spring when plants do not leaf out or bud properly because of bud damage.

If rain or snowmelt does not dilute salt placed on sidewalks and driveways, the soil becomes very salty and can damage plants. To save plants from salt damage, it is necessary to grade walks and driveways so that they drain away from your plants. Rinse all plants exposed to salt with water in the spring.

Although it is very difficult to reverse salt damage, you can do your best to prevent it by using something other than salt for a deicer. Kitty litter and sand are two options that work well to melt ice without damaging plants.

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Most water softeners utilize an “ion exchange” process where calcium and magnesium (minerals that make water hard) are exchanged for either sodium or potassium chloride in order to soften the water.

The amount of sodium or salt in your household water (after processing through a water softener system) can vary depending on the hardness of your water, but it certainly isn’t “salt water”. In fact, on average, those that own a water softener get less than three percent of their daily sodium intake from drinking softened water.

Keeping Indoor Plants Happy

But if you’re worried that the extra sodium from softened water may be hard on your plants, here are a few alternatives:

  • Collect and water your plants with rainwater. You can collect rainwater in a barrel or even a plastic garbage can at the bottom of a downspout. Collecting rainwater not only conserves water, but rainwater is usually quite clean. And FYI, rainwater is considered “naturally soft water” because it does not contain a significant amount dissolved minerals.
  • Some plants cannot tolerate chlorinated tap water. If your water seems to have a high level of chlorine (you’ll know by the strong chlorine taste or odor), let the water sit in your watering can for a few days to dechlorinate.
  • Use bottled water to water houseplants–but this can be rather expensive.
  • Use water from a reverse osmosis tap to water your houseplants. After the initial cost of the RO unit, reverse osmosis water is generally very inexpensive—just pennies per gallon.
  • Use potassium chloride instead of regular salt (sodium chloride) pellets in your softener’s brine tank.Potassium is a plant nutrient and is fine for plants and soils.

Keeping Lawns and Gardens Happy Outside

For outdoor watering, most water softeners have a bypass valve that allows you to temporarily bypass the softener to access untreated water for your plants. Refer to your softener’s owner’s manual or contact a water treatment specialist in your area to learn more.

You may also consider having a separate line to the outside tap installed by a plumber. This outlet allows you to water plants, trees and landscape with untreated water, but enjoy all the benefits of softened water in the home.

Mainly, look to your plants for clues. While calcium and magnesium (found in hard water) can be helpful plant nutrients, too much of a good thing isn’t so good. Some plants don’t do well when watered with “hard water”. On the other hand, some plants have a difficult time with softened water. So pay attention to your water quality and look to your plants for clues.

Oh How Does Your Garden Grow?

Gardening can be a lot of fun. But outdoor and indoor plants can prove to be finicky. So water quality aside, here are four tips that might prove helpful when watering household plants, lawn and gardens:

Not sure what kind of water you’re giving your plants right now? Find out if your household’s water is hard, soft, or something in between. Download WaterTech’s HARD WATER GUIDE to learn the tall-tale signs of hard water and what can be done about it. Or contact a local authorized water treatment professional to find out what’s in your water.

13 comments

I have a beautiful lawn that I am wanting to maintain well for the Summer. I have been looking for information to see if a water softener will affect my lawn, and it looks like it won’t, but I still have to keep an eye out. One thing that I was told was to water at night, but now I’m seeing to water in the morning, so I will have to test it out.

My lawn was affected by our water softener. I would recommend using the bypass

Don’t do it, it will kill your plants. In learning the hard way. I just got one and my poor lemon tree has yellow spots. Look for yellow spots in the tips of all plants.

What about soft water using potassium pellets?


The Myth of Using Gypsum for Lawns to Raise Soil pH

Myth #3: Gypsum for lawns is a great liming material and will effectively raise soil pH.

While gypsum is useful in many ways, this gypsum myth applies only to gypsum as a soil acid neutralizer. While there are reports of gypsum raising pH, this is mainly restricted to agriculture and not so much for lawns. I talk to people all the time who use gypsum in an attempt to neutralize acidic soil, not realizing it will not raise the soil pH at all.

Gypsum is a great product and a good soil conditioner, but there are no miracle cures. It is great for adding calcium and for solving some problems lime alone can't do. These are explained below.

At times the benefits of applying gypsum for lawns can be countered by a few disadvantages. Some of the possible disadvantages is nutrient leaching leading possibly to nutrient deficiencies. Before adding anything to the soil, it is always advisable to make sure it is needed first.

Gypsum is a great product and a good soil conditioner, but there are no miracle cures. It is great for adding calcium and for solving some problems lime alone can't do. These are explained below.

At times the benefits of applying gypsum for lawns can be countered by a few disadvantages. Some of the possible disadvantages is nutrient leaching leading possibly to nutrient deficiencies. Before adding anything to the soil, it is always advisable to make sure it is needed first.

What is Gypsum for Lawns?

Gypsum that is used for lawns (CaSO4) is the same material used in gypsum board, also called sheet rock. Like limestone used for lawns, gypsum, too, is a Ca+2 (calcium) material. However, gypsum also contains sulfur (SO4) that acidifies the soil.

Dr. Nick Christians, Iowa State University, Professor of Horticulture, states: "Whereas the Ca+2 [calcium] in gypsum has the potential to neutralize H+ [hydrogen] in the same way as lime, the sulfate forms sulfuric acid (H2SO4), which acidifies the soil and balances the effect of the Ca+2." (Fundamentals of Turfgrass Management p.102) In the end, the gypsum neither raises nor lowers soil pH.

In other words, when used as a liming material, the sulfur cancels out the benefits of the calcium and you end up with little or no pH gain.

What is Gypsum for Lawns Used For?

Gypsum has three primary uses on lawns.

The first purpose for gypsum is when it is used on soils with excessive amounts of salt (Na+). Too much sodium in soil will damage good soil structure by displacing other elements needed by plants. Salt is probably most damaging on clay soils.

Applying gypsum for lawns will dislodge the sodium which slowly restores the proper soil structure. Once dislodged, the sodium leaches below the root zone and away from plants. It is an important part of improving soils affected by salt.

Sodium can enter soil from many sources. In parts of Texas, septic tank overflow water must be sprayed via a sprinkler system (Aerobic Treatment Unit) instead of the conventional leaching system. Septic water contains sodium and heavy metals that may need to be monitored.

Other sources are runoff from winter road salt trucks and along coastal areas. Many western states also have problems with excessive salt.

The second purpose for using gypsum for lawns is when calcium is needed, but you do not require a change in the soil's pH. Calcium (lime) is needed by plants in large amounts and, therefore, calcium makes up about 65% of the soil's cations. Only Magnesium can equal calcium in total amounts needed by plants.

However, you may have sufficient calcium (lime), but the calcium may not be available to plants. Solid lime from granulated limestone applications must be dissolved first before it can be used. That can take up to two years. Gypsum doesn't take as long as limestone to break down and is more quickly dissolved, so it can be used by plants.

You can also try liquid calcium, such as CaCl (calcium chloride,) which is immediately available and can be taken up by plants from the moment it is applied. (Super-CalВ® from AgriGro is a good source for liquid calcium. Super-CalВ® also contains organic acids that dissolve solid lime, so it, too, can be used.) Using Super-Cal calcium, delivers immediately available calcium, but due to the organic acids will continue to deliver calcium for a few months more.

The third purpose for using gypsum is to reverse soil aluminum toxicity in soil. Aluminum is not an essential element for plant or animal life even though aluminum is found in soil in large quantities. Aluminum only becomes toxic in acidic soils. Only acidic soils below 5.0 pH and especially below 4.5 pH are greatly affected. Gypsum for lawns applied to the soil can quickly penetrate to the sub-soil area in the root zone where surface applied lime usually can't reach.

Soluble aluminum toxicity damages root growth and decreases root penetration, thus affecting plant health. Only the few acid loving plant species (blueberries, etc) have high aluminum tolerances.

Soluble aluminum testing is not always part of the standard soil testing regimen. If not, and you would like it done, you will need to request it.

Another misconception About Gypsum

If you search the internet you will find many sites on gypsum use. University tests conducted on gypsum's ability to soften landscape soils almost always differs from the many claims in home landscape forums. For that matter, even some researchers sometimes disagree on the benefits of gypsum.

Keep in mind that gypsum works differently in agricultural areas due to extensive and aggressive soil maintenance. The soil is often turned over to prepare for planting new crops, compared to lawns which are never turned once the lawn is established. In agricultural settings gypsum has proven itself and can improve heavy clay structure, improve plant root depth, drainage, etc.

However, gypsum does little to soften hard soils in home landscapes, as is often believed. Home soils are not easily affected by gypsum due to soil layering, heavy compaction, high organic content, etc. Coarse soils can actually be damaged by applying gypsum. Magnesium deficiency from gypsum for lawn application can result in some situations.

Gypsum will increase water filtration in saline soils, however. Salt prevents water absorption and blocks absorption into the roots. When the salt is removed by gypsum, the soil can again do its job in absorbing water and making it available to plant roots.

Here is a True-Life Example

I was recently speaking to a person living along the Gulf Coast of Texas who applied gypsum for lawns and spoke about how it helped break up his hard clay soil. He claimed he now had better water filtration. He didn't realize that it was the salt from the Gulf, especially salt water from the last hurricane that affected his soil and the gypsum corrected the problem.

To learn more about soil salinity and how gypsum can help, click on the link: Soil Salinity Problems and Cures

Special thanks to Anthony Meldal-Johnsen, Soil Scientist from the Western Cape, South Africa. He contacted me and pointed out some of the uses and benefits of gypsum, especially on agricultural sites.

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Repairing a Salt-Damaged Lawn

There is little point in reseeding or overseeding a lawn that has a high level of salt buildup. Without flushing out the salt beforehand, the new grass will absorb the chlorides in the soil and eventually suffer the same fate as the grass you’re replacing. Once you’ve adequately flushed salt out of your lawn in the spring, take your time to reseed your lawn the right way. While salt damage in your yard is nothing to shrug off, it also isn’t the end of the world. With a little foresight and prevention, you can protect your lawn and treat the damage before it’s irreversible.

About Wikilawn

Wikilawn’s mission is to provide the best resources and information to help you enjoy your outdoor spaces the way you want. Whether you are a DIY, lawn-loving, gardening guru, or someone who wants help in picking a local lawn care professional, we can smooth your path to a beautiful backyard!

About Wikilawn

Wikilawn’s mission is to provide the best resources and information to help you enjoy your outdoor spaces the way you want. Whether you are a DIY, lawn-loving, gardening guru, or someone who wants help in picking a local lawn care professional, we can smooth your path to a beautiful backyard!


Watch the video: Green Thumb Episode 14 Protecting your plants from salt damage with Ryan Bates