How to Make Soil Acidic

The ideal pH level for most types of soil is between 6.0 and 7.5. When measuring the pH level of soil, this level indicates the soil is either slightly acidic, neutral, or slightly alkaline. Although this is true in most situations, there are times when soil may need to be more acidic, as certain plants, flowers, shrubs, and trees require acidic soil to grow. When acidic soil is necessary, a soil amendment can be performed to make the soil more acidic.

The good news is that property owners can make their soil more acidic with little-to-no professional assistance. There are four main methods of doing so, including adding sulfur, iron sulfate, acid fertilizers, or peat moss. Each method requires a careful and unique application process to ensure optimal results and safety. Let’s take a closer look at the different methods and the overall process used to make the soil more acidic.

Test Soil pH First

Before you add anything to your soil to make it more acidic, you should make sure the pH is not already at an appropriate level. The pH scale ranges from 1 to 14, with 7 being neutral. Lower numbers indicate the soil is more acidic; higher numbers mean the soil is more alkaline. There are four ways in which you can test your soil pH:

• Professional testing
• DIY soil-testing kit
• Vinegar test
• Analyzing surrounding weeds

The best method to use is professional testing. This involves taking a sample of your soil and sending it to a local cooperative extension office. The office can, then, test the soil sample for you and provide other details, such as the nutrient content and levels in your soil. This ensures the most reliable results when determining the pH level of your soil.

You can purchase DIY soil-testing kits online or at many feed stores, and they are typically very reliable. If you do not wish to spend any money, you can get a fair approximation of the acidity of your soil by conducting a vinegar test. This involves pouring a small amount of vinegar into your soil. If there is fizz, it suggests your soil is not acidic. You can also check the types of weeds (if any) that grow in your yard. Certain weeds and plants — such as silvercup, dandelion, and plantain — grow better in acidic soil.

Adding Sulfur

Many prefer sulfur over other soil amendments because it is very effective at acidifying the soil. In addition, sulfur causes a change in the pH of the soil that can last for several years, which can reduce costs by cutting down the number of necessary soil amendments. It is important to apply the soil properly, however. You should first conduct a soil pH test to determine how much sulfur you will need to add. After application, you will need to allow time for the sulfur to acidify the soil, as it takes longer on average than several other soil amendments used to acidify the soil. It is best to add sulfur in the fall or summer, before or directly after the peak spring season.

Mixing in Iron Sulfate

Iron sulfate works differently than sulfur; iron sulfate is primarily used to treat iron deficiency in the soil, but it can also lower the pH level if enough is applied. The primary benefit of iron sulfate is that it works faster than sulfur does, and many see a lower pH level in as little as three-to-four weeks. The drawback, however, is that it is not as effective as sulfur, and will not work as well for soil closer to a pH of 10 or higher. It is also more important to get the exact needed amount of iron sulfate and apply it properly, as applying too much may damage the plants.

Using Acid Fertilizers

Acid fertilizer is a great way to allow acid-loving plants the ideal soil they need to grow, while at the same time not affecting the general acidity of the soil in your lawn and garden. Many home-and-business owners place acid-loving plants, flowers and trees directly next to vegetation that needs more neutral or alkaline soil. When this occurs, acid fertilizer is often the best solution, as you can directly apply it to plants that need the acidic soil so that it does not damage nearby plants.

Adding Peat Moss

Peat moss, also called sphagnum peat moss, can be an effective way to lower your soil acidity when applied correctly; however, it may not work well with soil that is very alkaline. You will also need to apply a generous amount of peat moss (approximately six inches) to the soil for the best results. The good thing about peat moss is that it can produce long-lasting results. In many instances, soil can remain acidic for more than two years after applying peat moss. Also, consider adding organic materials into the peat moss. This will help lower the pH level even further. Peat moss is safe and natural to use, and it is a good option for those who have less experience lowering the pH level of soil.

Which Plants Need More Acidic Soil?

There are certain flowers, fruits, vegetables, shrubs, and trees that need acidic soil to thrive. Among the most common include:

• Azalea
• Evergreen shrubs
• Dogwood
• Magnolia
• Hydrangea
• Most vegetables
• Blueberries
  Cranberries

It is important to understand the soil acidity your plants require before planting. If you want to plant any of the aforementioned plants but your soil is not acidic enough, it may be best to make your soil more acidic and wait until the next planting season.

The good news is that there are many other types of plants, trees, and shrubs that do well in neutral and alkaline soil. Choosing one of these in the meantime while you work on making your soil more acidic is a good idea.

Contact The Soil Experts

If you are looking for more information about acidifying your soil, the team at Dirt Connections can help you get the right soil for your lawn and garden and answer your questions or concerns. Give us a call or send us an email today for a prompt reply from one of our soil experts. We are also happy to assist you with any other projects involving soil or fill dirt.