Lime, which is also known as calcium carbonate or limestone, can be beneficial to the lawn. It helps to neutralize the acidity in soil and it raises the pH to a slightly acidic level, which is where most turf grasses grow best. Testing the soil and following guidelines for applying lime will ensure that you are applying the lime in the best way possible to benefit your lawn.
Why Add Lime to Your Soil?
For most types of grass, the ideal pH level for your soil is between 5.8 and 7.0, which is slightly acidic. Some grasses do better when the pH is higher and others do well when it is lower. For example, Kentucky bluegrass, ryegrass, and fescues are cool-season grasses and they do better with a slightly higher pH, which means that the soil is more alkaline.
On the other hand, warm-season grasses prefer a more acidic pH, which is lower. When the pH of soil becomes too acidic, the problem is that the nutrients that grasses depend on for proper growth, including nitrogen, phosphorus, potassium, and calcium, are no longer available for the grass to grow properly.
When you apply lime, it helps to increase the pH of the soil and make those nutrients available to your lawn.
Test Your Soil pH Level
You can buy do-it-yourself soil pH test kits or soil pH meters to find out whether you need to add lime but they will not recommend how much to add. Most state or county cooperative extension agencies actually come out, test your pH, and analyze your soil to recommend how much lime you should apply to raise your soil’s pH level.
Not only do you receive accurate test results but it is helpful to have the recommendation from them so that you add the correct amount of lime.
What Is the Best Time to Add Lime?
It can take several months for lime to break down and change the pH level of your soil. The best time to test your soil is in the spring, just as the soil begins to get warm. You can apply lime at this time and you can apply it in the fall.
During the fall and winter months, there is a cycle of freezing and thawing along with plenty of rain and snow. These events will help to break down the lime so that it can work to raise the pH level of the soil. Just remember that you should never apply lime to a lawn when it is dormant or stressed.
What Kind of Lime to Buy
There are two types of lime: calcitic lime and dolomitic lime. Calcitic lime has calcium and it is better for the lawn because calcium benefits plants. There are several types of calcitic lime, including the following:
- Agricultural ground limestone
- Pulverized limestone
- Pelletized limestone
Both pelletized and pulverized limestone change the pH of the soil quickly and pelletized limestone is the easiest to apply. The soil test results will recommend how many pounds of pure calcium carbonate to apply. You should look on the bag label for the limestone you buy to find the calcium carbonate equivalent.
The Best Way to Apply Lime
First of all, lime should only be applied to a dry lawn. The lawn should not be dormant or stressed. It will be easiest to change the pH of the soil by adjusting it before you plant grass seed or lay the sod. If that is possible, you will mix the limestone with the top five inches of the soil. If you do this, you may not need to add lime again for several years.
If you are going to add lime to an existing lawn, you need to aerate the lawn with a core aerator. This way, the lime will be able to mix with the soil. Then you can use a rotary spreader to apply the limestone to your yard. You should cross the yard in perpendicular directions to make sure that it is entirely treated with the lime.
The results of your soil test will tell you how much lime needs to be added and it is very important to follow their guidelines. If your soil needs more than 50 pounds of lime per 1000 square feet, you will need to apply half in the spring and half in the fall. Once you apply the lime, be sure that you water your lawn to remove any lime from the grass.
After several months, you need to test your soil again. If your soil pH is where it needs to be, you won’t have to do anything else but you will find out whether you need to add more lime. Once you get the pH level of your soil where it should be, you can check it once every year or two to make sure that it is staying where it needs to be. The most important thing to remember is to test your soil before you add lime.
Types of Lime
There are different types of lime and it is important to understand them so that you can choose the right lime for your yard. They all have the same goal of raising the pH of the soil to the neutral range so that the nutrients in the soil will be available to plants and grass. Take a look at some of the different types of lime:
- Ag Lime: This type of lime is agricultural lime, which is recommended for agricultural uses rather than a garden. It is coarse limestone and it takes a very long time to break down. It should be used in large areas where crops are planted.
- Pulverized Lime: Pulverized limestone is a powdery form that is made by crushing limestone rock. The benefit is that it breaks down very quickly and raises the pH level. However, it is very dusty and difficult to transport.
- Pelletized Lime: To solve the problem of transporting pulverized lime, people made a pelletized form. There are also enhanced forms of pelletized lime that may have polymers, organic acids, and micronutrients added. Pelletized lime is easier to transport and spread. If it is enhanced, it can help to keep nutrients in the coil where they are needed. However, it is important to buy a high-quality pelletized lime to ensure that it does its job.
Liquid Versus Dry Lime
Liquid lime is used for industrial applications, including the sides of roads or on a golf course. It makes it easier to spread across large areas but it doesn’t necessarily give the soil exactly the amount of lime that it needs. Dry lime can be more evenly distributed and is more reliable.
Calcitic Lime Versus Dolomitic Lime
There are two sources for lime and calcitic lime is the preferred source because it has calcium in it. Calcium is a neutralizer and benefits soil and plants because it is an important macronutrient for plants. Dolomitic lime benefits soil that is lacking magnesium.
The Benefits of Applying Lime to Your Lawn
Taking care of a lawn includes many different processes. You need to feed the lawn, seed it, weed it, and mow it. If you do all of those things but the pH levels of the soil is off, you will not have luscious green grass.
You need to test the pH level of the soil and make sure that it is in the correct range to allow grass to receive the important nutrients from the soil. If the pH level is off, the lawn will not receive all of its nutrients.
There are many benefits to applying lime to your lawn, including the following:
- It balances the pH level of the soil.
- It provides calcium and magnesium so that grass can grow and survive stressful situations such as drought, extreme temperatures, snow, and excessive rainfall.
- It adds nutrients to the soil.
- It helps grass grow stronger roots.
- It boosts the effectiveness of herbicides and fertilizers.
- It helps new seed or sod to take root and grow.
- It benefits positive microorganisms that are in the soil.
- It maintains and restores soil.
Lime per Acre
It is important to have the soil tested to determine the exact needs of your soil. Once the test results are in, the agency will tell you how much lime you need to add per acre. In general, it takes 1.2 tons of agricultural lime per acre to raise the pH of the loam soil by one point. It is half that for sandy soil and almost double for clay soil.
You need to know the composition of your soil as well as the pH level and it is best to have a test conducted by a professional soil-testing agency to find out the exact recommendation. In general, 1.2 tons of lime is the equivalent of 48 standard 50-pound bags of ground agricultural limestone. This is what it would take to raise the pH of loam soil by one point.