If your lawn doesn’t look quite as lush as it once did, you might try to help it by applying fertilizer or making sure it’s thoroughly watered. But if these interventions don’t seem to make any difference, the problem might be the acidity of your soil. And the solution might be lime.
When your soil gets too acidic, it drastically affects the health of your lawn. Adding lime to your soil changes the pH, making it more alkaline so your grass is happier.
So, before you spend a lot of time and money trying different fertilizers and causing more damage, let’s take a look at how you can tell if your lawn needs lime.
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What is Soil pH?
Soil pH tells you if the soil in your lawn is acidic or alkaline. The pH scale ranges from zero to 14. The low end of the scale is acidic and the high end is alkaline. Seven, which sits right in the middle, is a neutral pH.
Some soils are naturally acidic, and many things can affect soil pH. They include:
Region. For example, soil in the Midwest United States is more neutral. Head to the East Coast, and it gets acidic. Go to the West Coast, and it gets more alkaline.
Rain. Generally, rain itself is acidic, especially as you get closer to urban areas with a lot of pollution. In areas with a lot of rain, the soil tends to be more acidic.
Fertilizer. Fertilizers that have ammonium convert to nitrate in the ground, raising the soil’s acidity.
Microbes. Microbes living underground decompose organic materials, producing carbon dioxide and making the soil more acidic. This, in turn, kills off the beneficial microbes that help your grass grow.
The only reliable way to determine the pH of the soil is to test it. Although every type of grass is different, most prefer a pH between 6 and 7.
How to Know When to Use Lime on Lawn
Lime is nothing more than pulverized limestone. It’s a natural soil amendment that contains calcium carbonate, which reduces acidity.
Here are seven signs that you may need to add lime to your lawn.
A lot of weeds love acidic soil. If you see a lot of dandelions popping up, there’s a good chance your lawn needs lime. Lowering the acidity will make the environment less favorable to weeds and allow your grass to come back stronger as there won’t be as many weeds to compete with.
2. Yellowing grass
When your soil pH gets too low, the soil is too acidic to support the beneficial microbes in the ground. These microbes break down nutrients, making it easier for the grass to absorb them.
If you notice yellow patches in your grass, there’s a good chance that the microbial activity has slowed down because the soil is too acidic.
3. Clay or sandy soil
Certain types of soil are just more acidic than others. You should be aware of the type of soil you have so you know whether to expect problems with acidity.
Clay soil is naturally more acidic and will likely need lime occasionally. Sandy soil itself isn’t necessarily more acidic, but its texture results in a lot of runoff, which can leach nutrients from the soil, leading to increased acidity. With sandy soil, expect to add lime every other year or so.
4. No effect from fertilizer
When you see that your grass isn’t looking its best, your first instinct might be to add fertilizer. If you don’t see any improvement in your lawn even after fertilizing it, then there’s a good chance that the soil is too acidic.
It’s always best to check your soil before adding fertilizer. If you add too much too often or use the wrong kind, you can actually make soil acidity worse.
Moss thrives in acidic soil and loves moist, shaded spots of your yard. If you see a lot of moss growth around the bottoms of trees or along walls and other areas that aren’t in direct sunlight, you may need to add lime to your lawn.
6. Difficulty bouncing back from stress
Healthy lawns can usually bounce back from stress pretty easily. But if your lawn is having a hard time recovering from something like a drought, it might be because the soil is too acidic and it isn’t able to get the nutrients it needs.
7. Excessive rain
As mentioned, a lot of rain can wash away the nutrients in your soil, specifically magnesium and calcium. Eventually, this causes the soil to become acidic. Generally, the heavier and more frequent the rain, the more often you will need to apply lime.
Now that you know what to look for, it will be easier for you to identify when your lawn might need lime to lower the acidity of the soil.
Note that the first step in treating your lawn with lime should always be a soil test. This test will confirm if you do in fact need to add lime and tell you how severe the problem is so you know how much lime to add.
The best time to test soil is in the fall. When you add lime at this time of the year, it has enough time to work into the soil and alter the pH before the grass begins to actively grow again in the late spring and throughout the summer. For the best result, aerate your lawn before adding any lime.
Retest the soil a few months later and add more lime if needed. Once you get the pH to between 6 and 7, your soil should be good for two years or so until it needs another application.