Acidic Soil: What It Is, How You Can Change It

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Finding the right soil pH is important for the health of your plants. A proper pH balance helps plants develop strong root systems and uptake vital nutrients. While many gardeners focus on adding organic matter to their soil, testing soil pH levels is equally important.

Once you find your soil's pH level, you can add things like limestone or elemental sulfur to balance it out. Acidic soil can be a real problem for your plants. It can stunt their growth and prevent them from absorbing basic nutrients needed for healthy plant development.

In this article, we'll explain all about the importance of pH levels in your soil and how you can adjust them to help keep the plants happy and thriving. Let;’s get started.

What is Acidic Soil?

Acidic soil is soil that has a pH level of less than 7.0. This means that the soil is more acidic than neutral and can challenge plants to grow. The most common causes of acidic soil are high levels of rainfall, pollutants, and chemical fertilizers. The soil pH scale ranges from 0 to 14 with 7 as neutral.

Acidic soil
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Acidic soil can have a harmful effect on plant growth by inhibiting nutrient uptake, damaging root systems, and causing leaf discoloration. It can also be a haven for pests and diseases.

Evaluating Soil

Identify Your Soil Type

Before testing your soil or adding anything to it, it is important to know what type of soil you have. Understanding the ecology of your land will help you determine if acidic soil is a result of natural conditions or something that you can fix.

For instance, well-drained soil and loose soil will be easily altered, while compacted soil with lots of clay in it will be difficult to change.

Understand Your Soil pH

Soil pH is a measure of how acidic or alkaline your soil is. A pH of 7 is neutral, below 7 is acidic, and above 7 is alkaline. The lower the pH, the more acidic the soil. Soil pH value can be affected by many things such as rainfall, organic matter, minerals in the soil, and the types of plants growing there.

Consider What You're Planting

Some plants prefer more acidic soil than others. For example, blueberries and azaleas thrive in acidic soil, while rhododendrons and dogwoods prefer more alkaline soil. If you're trying to grow a plant that prefers a different pH than your current soil, you'll need to adjust the pH.

Test the soil's pH

Testing the soil's pH is as simple as buying a kit at your local nursery, or you can ask your county extension agent for a soil sample and testing instructions. Once you've tested the pH, make plans to raise or lower it depending on what kind of plants you want to grow and their preferred pH level. The good news is that there are simple DIY soil tests that you can do.

Have Your Water Tested

Your water supply might be what is affecting the soil's pH level, so have a sample of your well or tap water tested to see what its pH is. If you don't test the soil and the water, you're not going to know whether your problem is with your soil or your water supply.

How to Change Soil pH

Make sure you check your soil’s pH every year by sending a soil sample to your local extension office to have them perform the test for you.

 

Increasing Soil pH

To make soils less acidic, the common practice is to apply a material that contains some form of lime. Ground agricultural limestone is also frequently used. Here are other ways of increasing the pH level of your soil:

Increasing Soil pH
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Pick a Liming Material

There are many liming materials on the market, and they come in different forms. These ground limestone products include pulverized, granular, pelletized, and hydrated. Depending on your soil type and the amount of moisture in the ground, one of these products might be a good option. 

Pulverized lime is finely ground and easily absorbed by the soil. However, it's more difficult to spread because it can clog the applicator. Granular and pelletized lime is less likely to clog when spread with a fertilizer spread over turf areas.

However, it's not as effective at altering the soil pH. Hydrated lime should be used with extremely acidic soils because it's more water soluble and can quickly increase the soil's pH. Some lime sources contain micronutrients like dolomite, a mixture of calcium and magnesium carbonates.

However, you should only use dolomite lime if your soil is magnesium deficient. Do not add more magnesium to soils that are already high in it.

Consider Adding Wood Ashes

Wood ashes can also be used to increase the pH of acidic soils. The potassium, calcium, phosphate, and boron in wood ashes help to make the soil more alkaline and provide some nutrients to plants. 

When using wood ashes, it's important to take into consideration the amount of sodium present. However, wood ash is not as effective as lime, but it can dramatically increase a soil's pH over time.

Due to this, you should closely monitor your soil as you apply wood ash. Keep the ash from contact with any plant roots or germinating seedlings because it may damage them.

Apply the Liming Source

Once you've determined that your soil is acidic, the next step is to add a liming source. A liming source is an agent that helps raise the pH of acidic soils. There are many different liming sources available, but the most common are limestone and lime.

Water the Soil Regularly

Putting a liming source into your soil is not enough. You must water it to help it move through the soil to where you want it. Lime moves through the soil very slowly, so be patient; wait at least one growing season before testing your soil again.

Decreasing the Soil pH

Some types of fertilizers can also help acidify the soil and most of them are safe to apply. These acidifying fertilizers include monoammonium phosphate, ammonium sulfate, diammonium phosphate, urea, and ammonium nitrate. Make sure you read the label on the fertilizer bag to determine if it’s acidifying fertilizer.

Use Organic Materials

Over time, organic matter such as pine needles, compost, or composted manure can acidify the soil. If you have added organic mulches to your soil in the past, test your pH annually. Organic matter is also good in improving soil drainage and aeration.

Consider Applying Sulfur to Lower Soil pH

Sulfur can help adjust the soil's pH to desired levels. It is especially helpful for high-pH soils. However, sulfur does not last as long as lime, so you may have to reapply every few years. You should use elemental sulfur rather than sulfate or sulfite forms of sulfur that can be harmful to plants.

An excellent way to lower the pH value of small beds or garden areas is the addition of sphagnum peat. Sphagnum peat is also a good source of organic matter. Granular sulfur is also the safest, least expensive, but the slowest acting product to use when lowering your soil pH. The addition of sphagnum peat to large areas would also be cost-effective.

Apply Aluminum Sulfate if Soil pH Is too Low

If the soil pH value is too low, you can apply aluminum sulfate to increase the acidity. This compound makes the soil more acidic due to a chemical reaction involving aluminum. Be sure to read the product label to ensure that the aluminum sulfate you are using is specifically for agricultural use. Also, avoid applying aluminum sulfate if the soil is already too acidic.

Apply Aluminum Sulfate if Soil pH is too Low
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Till the Materials into the Soil and Water Well

When applying lime, sulfur, or aluminum sulfate to the soil, be sure to till them into the soil and water well. This will help the materials to dissolve and move through the soil so that plants can absorb them. If you do not water your fertilizer well, plants may not receive all of its benefits.

Rinse Your Plant After Application

If you are applying any fertilizer to your plants, be sure to rinse them off with water after application. This will help to remove any residue that may remain on the foliage and prevent any damage from occurring. 

If sulfur or aluminum sulfate gets on the leaves of your plants, you'll need to rinse it off with a hose. Failure to rinse them off can result in burns to the leaves and damage to your plants. Watering your plants will also help the compounds.

FAQs on Acidic Soil: What it is and How You Can Change it

What happens when the soil is acidic?

Soil acidity decreases the availability of plant nutrients such as phosphorus and molybdenum. It also increases the availability of some toxic levels, such as manganese and aluminum.

Is acidic soil good for plants?

No, it's not. Acidity can stunt a plant's growth and make it more susceptible to pests and disease. However, most plants thrive in slightly acidic soils because that pH affords them good access to all nutrients.

Why is it important to control the pH of the soil?

A soil's pH is one of its most important characteristics because it influences the availability of essential nutrients for plants. By managing the pH, you can ensure your plants have what they need to thrive, increasing yields and decreasing inputs.

Final Thought on Acidic Soil: What it is and How to Change it

There you have. Taking your soil acidity into account is an important part of gardening, whether you're trying to grow acid-loving plants or not. Luckily, it's not difficult to manage the pH of your soil, and most soils can be brought into a desirable range with a little effort. 

 

 

Kristina Perrin

Kristina Perrin

Kristina is an expert DIY home remodeler and mom to three. When she's not cooking or experimenting with new recipes, you can find her working on new home improvement projects or writing about her favorite kitchen appliances or DIY projects on Kitchen Infinity blog.

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