How to tell if your lawn needs lime

It’s difficult to know what products lawns need the most.  Below we share all things lawn lime so you’ll know how to tell if your lawn needs lime.  Spoiler alert: it’s a soil test.


What is lawn lime?

Lime is a common soil amendment used to adjust soil pH levels. It is made from ground limestone rock or processed limestone materials. There are three common types of lime.


Calcitic lime

Calcitic lime is made from pure calcium carbonate and is preferred for soils that have a pH level below 7.0.

Dolomitic lime

Dolomitic lime is made from a combination of calcium carbonate and magnesium carbonate and is preferred for soils that have a pH level below 6.0.

Hydrated lime

Hydrated lime is made by hydrating quicklime, and it is more caustic and therefore should only be used with caution.


How lawn lime works

Lime is used to raise soil pH levels by neutralizing soil acidity. Soil acidity is caused by the presence of hydrogen ions, which are released into the soil when organic matter decomposes or fertilizer is added. The lime reacts with hydrogen ions to create water and calcium ions, raising the soil’s pH level.


How to tell if your lawn needs lime?

Lawns that are grown in acidic soils (have a pH level below 6.0) benefit from lime applications. It is important to go by a soil test result to determine the exact amount of lime needed. Excess liming can lead to alkaline soil, and inhibit the growth of your lawn.

How to find out your pH

pH meters measure the actual pH level of the soil but do not take into account the soil’s buffering capacity. Buffer capacity refers to the soil’s ability to resist changes in pH, and can vary depending on factors such as soil texture and organic matter content.

Soil with a high buffer capacity will require more lime to raise the pH level than soil with a low buffer capacity, even if both soils have the same pH reading. Therefore, it is important to conduct a soil test that takes buffer capacity into account when determining the appropriate amount of lime to apply.


How much lime is needed?

Adding too much lime at once can result in a rapid increase in soil pH, especially quick lime, which can cause plants to go into shock. It is recommended to add no more than 100 pounds of agricultural lime per 1,000 square feet of lawn at a time.  These recommendations ensure that the pH level is adjusted gradually and the soil is not overcorrected.

How long does lime take to work?


lawn lime

The amount of time it takes for lime to work depends on the type of lime used and the type of soil. Fine-grained lime materials, such as pulverized lime, work faster than coarser-grained materials, such as pelletized lime. Generally, it takes a few months for lime to fully adjust the soil pH level.

Adding agricultural lime to the soil can raise the pH level, but the effects are often slow and gradual. It can take several months or even years for the full benefits of lime to be realized.


When is lime needed most?

Farmers who use high-nitrogen applications benefit from using lime because nitrogen fertilizers can increase soil acidity. Lime helps to neutralize acidity from repeated fertilizer applications. Additionally, the calcium in lime helps to improve soil structure in soils with low calcium levels.  Residential lawns are not cultivated to the extent of high-input farming.  This is why lime is uncommon in lawn care programs and not because it’s a secret or special product.


How easy is it to adjust soil pH?

Changing soil pH is a difficult and slow process that involves altering the balance of minerals and nutrients in the soil. Soil pH is largely determined by the parent material from which the soil was formed, and can be difficult to change because of the sheer bulk of minerals in the parent material.  This mass of parent material often makes needed lime applications impractical or cost prohibitive.

In addition, the benefits of lime are often short-lived, as the soil pH will begin to decrease again over time due to natural processes such as rainfall and the breakdown of organic matter.


How calcium is lost from the soil

Calcium is lost from the soil when it is leached out by water. This occurs more frequently in regions with heavy rainfall and tropical climates. In temperate regions, calcium is lost less frequently due to the lower rainfall amounts and frozen ground.


Cons of lawn lime

One downside of lime is that it can affect the availability of certain nutrients in the soil, mainly phosphorus, a macronutrient.   Additionally, excess lime can lead to alkaline soil if the soil is already above a pH of 7, which can hinder the growth of your lawn. It is important to only apply lime when it is necessary and to follow soil test results to determine the exact amount needed. It is also important to not overapply lime, as this can result in nutrient imbalances and pH shock.


Putting all the information together

It is unlikely that homeowners in temperate climates will need to apply lime to their lawn. Temperate regions typically have higher soil pH levels and lower rainfall amounts, which means that calcium is lost from the soil slowly.  However, if a soil test indicates that the soil pH level is below 6.0, it can be beneficial to apply lime. In these cases, it is important to follow soil test results and only apply the recommended amount. It is also important to monitor the soil pH level and reapply lime as necessary to maintain the desired pH level.

For homeowners, the use of lime on lawns may not be a practical solution. While it is possible to add lime to the soil to raise the pH level, the benefits are often short-lived and may not be worth the time and investment. The pH level of lawns is difficult to manage, even for professionals.   If you want to improve your lawn, there are several other worthwhile products and practices to do instead.

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