Adjusting Soil pH After Planting: the beginner’s guide

Are you worried about the higher pH level in the soil of your potted plants?

The right pH level in the soil will help to positively affect your plants, vegetables, and fruits. So, before you move ahead, don’t forget to test the soil pH level and see their actual condition.

If you observe that the pH level of the potting soil is not suitable for your plant, then the growth will not be proper.

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Know the pH Scale

The pH level of the soil is measurable by the pH units that reflects whether the soil is acidic or alkaline. The pH unit stands for the potential hydrogen to measure the ratio of hydrogen ions and hydroxyl ions in the water.

The neutral point is 7, while it can go up to 14.

A lower pH number indicates the presence of higher hydrogen ions makes more acidity. Contrarily, higher hydroxide ions can make the solution much more alkaline.

Hence, white vinegar has a pH level of 2.5 and is acidic in nature, whereas baking soda holds 8.3 on the pH scale. Conversely, water stands at a neutral level with a pH of 7.

It is no secret that the substance at both higher and lower ends of the pH scale can cause serious damage to the cells and organic materials.

This is the reason why gardeners must know in the first place how to check the soil’s pH levels.

Fortunately, after you determine the level, you can manage to change the pH level of the soil in potted plants. The unbalanced pH level, when adjusted, can benefit potted plants and outdoor plants.

The pH of Soil in Potted Plants

The range at which the most plant nutrients are accessible in the soil falls between pH of 5.5 to 7. Conversely, some plants may need a higher or a lower level of pH for their optimal growth.

If this level changes, only a few nutrients will remain available. All the plant nutrients should dissolve into the water for easy access to the plants. So, it is necessary to match the needs of the nutrient of the plant with the pH level.

Extremely Acidic Condition (3 to 5 pH)

Soil that is highly acidic indicates 3 to 5 pH on the scale due to washing out certain nutrients like Calcium, Magnesium, Potassium, and Copper. 

Acidic Condition (5.1 to 6 pH)

The 5.1 to 6 pH level in the soil of some potted plants discourages healthy growth in acidic conditions.

Between Slight Acid to Neutral (6.1 to 7 pH)

The range of pH between 6.1 to 7 is suitable for the growth of several plants. At these levels, the plants get enough nutrients to cultivate. Many microorganisms grow in the soil; having a neutral pH level makes it more fertile.

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Alkaline Condition (7.1 to 9 pH)

In alkaline conditions, elements like phosphorus, manganese, and iron are less. Since some plants don’t grow in such a state due to the presence of excess lime, this results in nutrient deficiency. 

DIY Soil Testing

First of all, collect the sample of soil in the potted plants, then get two tablespoons of them in two cups. After that, add a half cup of vinegar to the sample and then examine the reaction. If the soil sample turns to go fizz, then it is in alkaline condition. 

If you notice no fizz, then add a small amount of distilled water in the soil sample taking from the same place where you took the previous one. Add a half cup of baking soda to the mixture. At this point, if you notice fizz, your soil is acidic in nature. 

How does it work?

When you combine alkaline or acidic substances into the soil, there will be a fizzy reaction. Thus, indicating that your soil is either more acidic or alkaline. If you want more specific findings, get a soil test kit or a pH meter.

Soil-testing Kit

Plants need sufficient light, water, and nutrients to germinate. You are likely to know by now the need for soil pH, but what you may not know is the number of nutrients. Out of 17, a maximum of 14 plants gets from the soil. 

Usually, you are likely to need aluminum sulfate and sulfur, quality potting mix, and a new pot having draining holes. 

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How to Get a pH Testing Kit

The pH testing kits are available online or at the nursery plants and come with easy-to-follow instructions. For your convenience, here is a general way of testing pH.

Mix the water sample with other components and insert everything in the test strip. If the level is higher than the optimum range, you are likely to get the task of adjusting the soil. 

Ingredients like aluminum sulfate and sulfur have the potential to lower the pH level of the soil. However, you must measure the aluminum sulfate and sulfur carefully before you start applying.

The Repotting Process

A quality potting mixing can benefit the plants by adjusting the pH of the soil and its optimum level of moisture. Try to get a moisture control pot mixture to protect the soil from getting underwater or waterlogged. It is best suitable for use on potting and replanting of houseplants. 

Impacts of Soil pH on the Plant Growth

The nutrient level of plants varies depending on the pH of the soil. The growth of some beneficial organisms might hinder in extremely alkaline or acidic conditions. Whether the soil is extremely acidic or alkaline, certain plants will not grow or become unhealthy as some microorganisms will not thrive. 

Remember, every plant grows healthy when it germinates in its preferred pH levels.

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How to Lower Soil pH?

After testing, if you see the need of lowering the pH of the soil in the potted plants, follow the below methods.


One of the ideal ways to turn your soil acidic is by adding manure into the soil. It comes with several benefits – from lowering the soil pH levels to providing necessary ingredients, beneficial microorganisms to improving the soil texture and making the plants healthy. 

If you are fine with a slower process of lowering the pH of the soil, manure addition is ideal.

Tea Residues

When you need to lower the pH of soil a little bit, you can use the residue of used tea. Though it will fail to bring a major change in the soil pH due to the removal of acidity after brewing, you can still notice changes with constant use. 

Used tea contains several effective nutrients and components, including potassium, nitrogen, phosphorus, magnesium, copper and more that helps to grow plants healthy. Moreover, it also prevents the settling of snails and fire ants. 

Coffee Solution

Just like used tea, don’t throw away the residue of your brewed coffee, as it can effectively reduce the pH level of your potting soil. So, when you measure the soil pH is lower, make a mixture of the coffee remains and nitrogen. Add it to the soil to notice the result.

Nonetheless, if the potted soil requires a higher lowering, it is better to miss out on coffee remains. Instead, alter this with freshly ground new coffee beans that are not brewed earlier. Use it in a small quantity and slowly add to the soil while keeping close monitoring on the pH level.

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Also, refrain from touching the soil unnecessarily. This solution is far better for plants that require more acidic soil.

Vinegar Solution

Take a cup of vinegar and a gallon of plain water and mix them. You can either apply this mixture as it is into the potting soil. However, we suggest you begin at a slower pace by simply putting water on the plants.

Then after applying the solution, wait for a while and again measure the potted soil pH to notice the difference. 


If you seek to lower the soil pH using the faster method, use sulfur. You can apply sulfur in much higher amounts if your plants are not sowed into the soil. Besides, you may find various types of sulfur in the market, but choose aluminum sulfate that will instantly show results. 

All thanks to its ability to quickly dissolve in the soil. However, remain cautious as this solution can develop aluminum toxicity in a few plants. 


Discover the essential tips for adjusting soil pH post-planting at PlantGardener. Uncover the secrets to maintaining an optimal pH level for your plants, ensuring vibrant growth and a thriving garden. From identifying signs of pH imbalance to implementing effective adjustments, this guide provides a comprehensive solution. Elevate your gardening knowledge and cultivate a healthier, more robust garden environment. Explore the transformative impact of proper soil pH management with PlantGardener’s expert insights. Your journey to a flourishing garden starts here!

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While altering and preserving the pH of the soil, it is ideal to go for eco-friendly options like using coffee, vinegar, wood ash, baking soda, and similar ingredients.

This is because excessive use of chemicals can change the pH faster and create toxicity in the soil. Subsequently, it will have an adverse effect on plants, people, animals, or even the soil.

Although the chemicals may change the pH of the soil faster than these non-invasive methods, still it is undeniably poisonous.

However, occasionally you may use it in moderation. So, think wisely and plan accordingly to lower the pH of the soil in your potted plants

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