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Understanding Soil pH For Plant Health – GIY Plants

Understanding soil ph for plant health. Soil around a white card with the words soil ph written on it.

Understanding soil pH is essential for fostering optimal plant health. The pH scale, ranging from 0 to 14, indicates whether the soil is acidic or alkaline. A pH value below 7.0 represents acidic soil, while a value above 7.0 indicates alkaline soil. At 7.0, the soil is considered neutral. This pH balance affects nutrient availability and, thus, the overall plant health.

Why pH Matters

The pH of soil impacts a myriad of factors vital to plant health. Most notably, it governs the accessibility of nutrients. Certain plant nutrients are only soluble and, therefore, available to plants at specific pH levels. A slight deviation from the optimal pH range could restrict nutrient availability, affecting plant health adversely.

Understanding Acid And Alkaline Soils

Acidic Soil

Soil with a pH value below 7.0 is known as acidic soil. The level of acidity can vary, with pH 6.5 often described as slightly acidic and pH 5.0 considered strongly acidic. Acidic soil is usually rich in organic matter and minerals like manganese.

Alkaline Soil

On the other hand, soil with a pH value above 7.0 is considered alkaline. It typically contains high levels of calcium carbonate and other alkaline earth metals. These soils may be low in essential nutrients like magnesium, impacting plant health.

Testing Soil pH: Get to Know Your Soil

Man testing soil ph with meter and getting a neutral reading of 7.0.

We recommend testing soil using a soil test kit. This helps in understanding soil pH, allowing you to optimize conditions for plant growth. These kits are readily available at garden centers. Alternatively, you can send a soil sample to a lab for a more detailed analysis.

How to Adjust Soil pH

Once you know your soil’s pH, you can adjust it to the desired level. The key is understanding whether the soil is acidic or alkaline, then applying the correct material to change the pH.

Lowering Soil pH

If your soil is alkaline and you need to lower the pH, sulfur is your go-to amendment. When sulfur is added to soil, it reacts to form sulfuric acid, which reduces soil pH.

Raising Soil pH

In contrast, we add lime (calcium carbonate) to raise soil pH in acidic conditions. Lime neutralizes soil acidity by reacting with hydrogen ions in the soil, thereby increasing the pH.

Soil pH and Fertilizers

Fertilizers play a significant role in affecting soil pH. They contain varying amounts of acid or alkaline soil, influencing pH over time. It’s crucial to understand your soil type and pH before applying fertilizers.

A Balancing Act: pH Can Vary

In reality, pH can vary within certain soil types. Soil pH may also resist change, staying stable even when adding acidic or alkaline materials. Hence, minor, frequent pH adjustments are preferable over drastic changes.


To sum it up, understanding soil pH is crucial for optimal plant health. Maintaining the correct pH ensures that plants access essential nutrients, promoting strong and healthy growth. Always regularly test your soil conditions and adjust the pH as necessary. This careful balance will help your garden thrive, regardless of soil type.

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