How does soil pH affect plant growth?

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Plants are most important for the planet and everything existing on the planet.  Living things need plants for their survival. You all know that plants absorb carbon dioxide and, at the same time, release oxygen, which is very much essential for the survival of living beings.  

How does soil pH affect plant growth is very important to be known for many other purposes because it also helps in the water cycle, soil erosion and desertification, provide raw materials for medicines and clothing.

There are many more important factors which you all must know and help the plants to grow. For the plants to grow correctly, one of the main factors is the soil’s ph level. Furthermore, soils are classified according to their respective pH level. The scale of pH starts from 0 till 14, but the perfect pH level is supposedly 7.

Why is soil pH important for plant growth?

Soil pH is one of the most important factors which help in the growth of the plant. It is the measurement of the acidity of a soil. Ph is generally defined as the negative logarithm of the hydronium ions in a solution. The pH level of the soil is considered to be the master variable in soils.  One can measure the soil’s pH in a slurry of soil, which is mixed with water. Soil pH usually falls between 3 and 10 out of that 7 being the normal.

  •  The soils which are acidic nature have a pH below 7.
  • The soils which are alkaline nature have a pH level above 7.
  • Most plants have an optimum range of pH is between 5.5 and 7.5.

Soil pH can affect a lot of many other chemical processes. Plants nutrient availability is most affected by the pH level of the soil.  

Role of soil pH in plant nutrition and soil

The form of the nutrient in the soil changes due to the soil pH. It is always recommended to adjust the soil pH because it can help in the increase of important nutrients.  On the one hand, the availability of macro and secondary nutrients keeps on reducing with a low pH level. On the other hand, the availability of micronutrients keeps on reducing with a high pH level.

Adjusting these two is always recommended. The factors which affect the growth of a plant are:-

  • nutrient leaching
  • soil bacteria
  • toxic elements
  • nutrient availability
  •  soil structure

There is an enormous influence of soil pH on soil biogeochemical processes.  Soil pH is considered as ‘ master soil variable ‘ because it influences a multitude of soil’s chemical, physical and biological properties and processes, which affects a plant’s growth and biogas succumb.

Chemical, biological, and geological aspects of soil are interlinked because of the soil pH. Just because all the elements are interlinked, it needs to be taken proper care for a plant’s growth and life.  The pH of the soil can broadly be applied in two areas such as:-

  •  plant nutrition  
  • soil redemption
  • Nutrient cycling.

It is to be looked upon very seriously that soil’s pH level must not be too high and too low.  Different plants require a different level of soil pH.

What happens if the soil has a high pH?

A high pH level of the soil happens when the soil’s food contains a high quantity of pH. The process of absorption of essential nutrients by the plant is then disrupted when the soil’s pH is too high. The iron present in the soil with high pH is prevented from changing into a form that the plant can absorb.

The presence of sodium in the soil makes its pH value above 8.5, which is considered to be high. “Sodic soils” are the term used for soils that contain high pH. Soils with high sodium become dispersed and nearly impervious to water. Gypsum and sulphuric acid are added to the sodic soil to remediate.

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What happens if the soil has a low pH?

On the other hand, aluminum is liberated when there is a low pH level in the soil. The plant’s growth is stopped, and there is also a change in the intake of nutrients when the ph of the soil is low. Soils low pH can also cause the plant to suffer from manganese and iron toxicity, causing yellow spots and, ultimately, leaf death.  

Blighted leaf tips, stunted growth, yellowing of foliage, wilting leaves, leaf discoloration are some of the other symptoms which indicate that the soil contains a low pH level. 

Soils which have low pH are acidic nature. Manganese and aluminum become toxic to plants growing in soil whose pH level is lower than 5.0. These overloaded nutrients make the plant overloaded, causing the death of the plant.

How does soil pH affect plant growth is very important to understand because it is the most crucial part that helps in the overall growth and life of a plant.

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How does soil pH affect plant growth?

How does soil pH affect plant growth is advisable to know because it helps in the plant’s overall development. The soil’s pH level is the sole element that determines the growth of the plant because if its level is high, it is likely to disrupt absorbing essential nutrients, which may slowly cause the plant to die.

Excess of sodium happens when the pH level is high in the soil. And due to the low level of pH in the soil makes the leaves yellowish and ultimately leaf death.

Biodegradation is one such transformation where ecosystem engineers are involved in the transformation of substances in the soil. More specifically, biodegradation is the process where microbe’s reform contaminated soils by transforming contaminated substances into least or even more toxic forms.

Soil pH also influences such an important process and ultimately aids in the degradation process. Alkaline and slightly acid soils more likely enhance biodegradation, but the acidic environment makes limitations for this too. Biodegradation is very much important. If the rate of biodegradation is high, then eventually the toxic effects will be reduced rapidly. Still, at the same time, constant chemicals will always maintain their toxic consequence that is also for a very long tenure.

As the soil’s acidity level depends upon the soil pH; therefore, it needs to be looked upon as all plants require different pH levels. An imbalance of the pH level can hamper the growth of the plant. Too much high level of pH and too much low level can both be dangerous. It shall always be looked upon that plants that require adequate pH is present in the soil or not.

Sometimes if the top 6 inches of soil shows a proper pH above 6, the subsoil still becomes acidic. Sometimes it also happens that the pH of the subsoil becomes below 5.0 at that time; aluminum and manganese become much more soluble, thus leads the soil to be toxic for the growth of the plant. 

We may think that adding fertilizers can help in the plant’s growth, but the concept must be clear that out of all the fertilizer nutrients, the main nutrient that affects the pH of the soil is nitrogen.  We may also think that it actually improves the quality of the soil. Still, in reality, nitrogen can actually make the soil more acidic or more alkaline, and it solely depends on the kind of nitrogen being used.

On the other hand, the most acidifying phosphorous fertilizer is phosphoric acid. But at the same time, there is no effect of potassium fertilizers on the soil. 


Thus you may conclude that how does soil pH affects plant growth must be known properly. To maintain the pH level of the soil, you must make the soil less acidic. And for that, we need to apply materials that contain lime. For different kinds of soil, different quantity of lime is required. The most frequently used is ground agricultural limestone.

Home gardens have a different ph level of about 6.5 since the most likely range is supposedly 6.5 to 7 ( which is slightly acidic to neutral ), and many plants even need more acidic soil. In contrast, even some others are best in the soil, which is neutral to slight alkaline in nature. Therefore knowing how soil pH affects plant growth is very much important to maintain a healthy ecosystem.

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