Soil pH Explained: Acidic vs. Alkaline, What it All Means & How to Neutralize Your Lawn

You’ve probably heard landscapers talking about the importance of a “neutral” soil or the horror stories from neighbors about how their “acidic” lawn destroyed their grass. But beyond that… do you really understand what pH really means?

We’re here to talk about the difference between acidic vs. alkaline soil and how to neutralize or balance your soil’s pH levels— to foster a beautiful, green yard.

Understanding the pH of Your Soil

Simply put, the pH of your soil is a measure of its acidity or alkalinity.

It helps to first understand that pH is a unit of measurement for your soil’s hydrogen atom concentration. (That’s what pH stands for: potential hydrogen).

Acidic vs. Alkaline Soil

The pH scale is measured from 0 to 14, with the sweet spot being right in between, or pH 7. This neutral point of means your soil is in ideal balance, thriving and growing well.

Anything above 7 (from 8-14) is considered alkaline, while anything below neutral (from 6-0) is considered acidic. Acidic or alkaline soil can cause a number of problems for your grass and plants.

Acidic vs. Alkaline Soil

On the pH scale: High Number = Alkaline, while Low Number = Acidic

Alkaline soil contains excessive amounts of sodium, calcium, and magnesium— and is often called “sweet” soil. The soil becomes less soluble and has trouble absorbing nutrients, or allowing its surrounding plant’s roots, to absorb nutrients.

It’s often common in areas that get very little rain or for landscapes which are quenched with “hard” water, containing excessive amounts of lime.

Acidic soil often occurs from leaching and decomposition, where heavy waters wash calcium and magnesium out of your soil’s base or extra minerals/chemicals cause organic and inorganic acid levels to rise. This “sour” soil becomes toxic, harboring an excess of certain elements (like carbon dioxide or nitric and sulfuric acid), which can shock and kill certain plants.

Chemical fertilizers can over-fertilize and “burn” plants, heavy or acid-ridden rains can leach nutrients away in runoff, or certain kinds of mulch can increase your soil’s acidity. Even pesticide use can throw off your soil’s pH levels.

Here in Massachusetts, homeowners suffer from acidic soil problems, more often than not. Because of this, we’re going to focus on treating acidic soils, with a simple but very special remedy: lime.

Soil 101

The Power of a Lime Application for Acidic Soils

Too much decaying organic matter and oxidation from ammonium and sulfur fertilizers can mean bad news for your soil.

Lime is often a miracle worker for acidic soils, for a few reasons:

  1. Lime replaces hydrogen ions, raising your soil pH!
  2. Lime provides your plants with calcium and magnesium, which are important nutrients for your lawn, helping it to maintain resilience through high temperatures, drought and heavy snow or rainfall.
  3. Lime increases the availability of nitrogen, by hastening the decomposition of organic matter.

In addition, it’s hard to apply too much lime (though you certainly can if you tried hard enough), and a single application can go a long way.

Can Lime Help Your Lawn? Test Your Soil pH to Find Out!

Your lawn may require a lime treatment for a number of reasons. Maybe it’s dying in patches, getting overtaken by weeds or turning all kinds of old shades of yellow.

Here’s the thing though: these symptoms can be brought on by a number of reasons, like insect infestation, water, sun or salt damage, disease, etc. Lime may not always be the best solution for treating these disturbances, which is why you should always test your soil before applying limestone.

While you can purchase soil pH testers and do it yourself or send a soil sample into some place you found online and wait for results, the best way to test your lawn’s pH is to trust a local professional. A local lawn care expert can come to your home and take a sample and will know exactly how to ensure accuracy, read the results and help choose the right lime mix and ratio for your landscape.

Soil nutrients

Choosing a Lime Type for Your Soil

There are various types of lime, including agricultural, calcitic, dolomitic, hydrated, etc., which all deliver various benefits— and react differently with various types of grassses.

Most kinds sold for lawns are ground dolomite lime, containing a hefty source of calcium-magnesium carbonate; but lime shopping can be confusing for the everyday homeowner, without common knowledge of mineral-lingo and benefits.

While your soil test will tell you what your levels of calcium and magnesium are, you may not know which kind of lime to purchase. For instance, a dolomitic lime which contains more magnesium could be more useful than a higher calcium-rich lime, like calcitic. This is something a lawn care professional can tell you, easily, but you likely didn’t know off-hand.

Someone from our team at Green Sphere will also know the best time to spread the lime (like in the fall or spring, early in the morning!) and understand how it mixes with any of your other treatments.

Fertilize, Correctly

Speaking of considering how lime will mix with your other lawn treatments, we recommend fertilizing separately— laying your lime alone, or only with seeds, and applying fertilizer or compost at another time.

Your soil test will help to determine the right fertilizer for your landscape too! Fertilizing properly can help keep your landscape green and your soil structure healthy.

Download our Ultimate Guide to Fertilization for help choosing the best product, how to spread it and when to apply. It’s free, and even shares how to start your own compost, should you want to do all the yard work yourself!

Guide to Fertilization

 

Topics: Gardening, Lawn Care, soil