Gypsum Lawn Application

What is Gypsum?

Gypsum (Calcium Sulfate or CaSO4) is a relatively soft mineral naturally created as a byproduct of sulfide oxidation. Gypsum is found naturally in a crystal form in several states in the United States including Indiana, Iowa, and California.

One of the very first known uses for Gypsum in the United Stated was by Benjamin Franklin, who used Gypsum to make plaster for the walls of his home. Gypsum is also the main ingredient in chalkboard chalk, as well as drywall that is in most modern homes. Gypsum is also used in the making of glass, Portland cement, Plaster of Paris, and as an additive to medicines.

How Does Gypsum Help My Lawn?

Gypsum is a recommended application to resolve some soil issues in you lawn. Gypsum has been used in certain applications to reduce soil compaction, improve soil structure, increase air movement, and prevent reduce water run-off by preventing soil crusting.

Gypsum also has the ability to dislodge sodium (salt) in the soil. This ability of Gypsum may be the most useful of all because of the damaging effects salt has on lawns and plant materials in the landscape.

That being said, there are respected professionals that argue about Gypsums ability to reduce lawn compaction in the primarily clay soils of the urban Midwest. There is also a concern about using Gypsum that contains dolomite, which can raise the Ph of soil.

What Can Gypsum Do For Salt Burn On My Lawn?

In the winter when rock salt is applied to asphalt it inevitably gets into the lawn, whether it is spread by a salt truck or if it is piled on the lawn by a snowplow. Although the rock salt is essential to winter safety, salt is very damaging on lawns and plants.

When excessive rock salt (sodium) used on streets and driveways gets into the lawn, the salt damages the soil structure by displacing other key elements needed by the lawn. The use of Gypsum dislodges the salt and allows it to leach away into the sub-soils below the roots of the lawn, rendering it harmless to the lawn. Heavy watering is required in these areas to aid in the leaching process.

For the technically minded, here is some more information. Salt in the soil will prevent water absorption and block water from being absorbed by the roots of the lawn. Salt also raises the Ph of the effected soil, potentially retarding the growth of the lawn even more. When salt breaks down in the soil, salt releases chloride, which gathers in the blades of the lawn. In sufficient quantities, the chloride can discolor the blades and even cause the blade to die. If the section of lawn doesn’t perish, the weakened lawn is more susceptible to disease and competition from weeds.

Gypsum And Aeration: The Best Combination

Gypsum works best when it is in direct contact with soil, such as before you seed/sod or when you rototill your garden. For established lawns, the best results are found when Gypsum is applied after a lawn aeration. The aerator removes small plugs of soil from your lawn, creating holes about the size of your small finger. If the Gypsum is applied directly after the aeration it enters those holes and has direct contact with the soil in those holes. Applying Gypsum as a surface application is less effective than direct contact, such as after aeration.

Do I need A Soil Test Before Applying Gypsum?

Soil tests are tests we perform to check the levels of certain minerals in the soil. Soil tests also tell us the Ph of the soil, indicating whether it is alkaline, acidic or Ph neutral. Soil tests are always a good idea because other than a soil test there is no scientific way to determine the Ph or mineral content of your soil. Seasoned professional and horticulturalists can see some deficiencies in your lawn by the color, but without a soil test there is no accurate way to know the remedy. Gypsum is needed in your lawn when your lawn is low in calcium and high in magnesium, something only a soil test can tell.

If you are interested in a Gypsum application for rock salt damage on your lawn, then there is no need for a soil test. However, if you are interested in a gypsum application for lawn problems such as compaction or drainage, then yes, a soil test would be essential.

Gypsum For Salt Plant Damage

For the same reasons stated above, salt will also damage the plants in your landscape. Although not as common as salt in your lawn, rock salt ending up in your planting beds will still change the Ph of the bed soils and block the landscape plants from absorbing water. When this happens, evergreens with start to wilt, discolor, and die off. Deciduous plants will show visible signs as well, usually looking like burnt leaves.  Using Gypsum around the base of your landscape plants is also a valuable ability of Gypsum.

Is Gypsum Safe?

Yes Gypsum is safe. Pure Gypsum is a natural mineral that does not affect the Ph of the soil nor does it add or detract from the existing minerals already found in your soil. Gypsum has no plant nutrients, such as nitrogen, so there is no chance of plant damage when using it. Gypsum is also safe for pets and workers can handle the product without gloves or masks.

How Much Does A Gypsum Application Cost?

Depending upon the reason for an application, the quantity of Gypsum can vary significantly. The amounts of Gypsum for lawn applications can range from 20 – 50 pounds per 1000 square feet, therefore changing the material cost significantly.

If a lawn application is needed, the minimum application cost is $90. However, if the application is selective, such as for rock salt damage, then the costs can vary.

Recapping the Benefits of Gypsum

• Dislodges Sodium (salt) from the soil
• A faster way to add calcium to a lawn without changing the Ph
• Reverses aluminum toxicity in soil
• Increase water filtration is saline soils
• Treating dog urine damage in lawns
• Aids in water percolation
• Helps in soil aeration