If you have a hydroponic system at home and the plants growing in it do not grow well. Then the 95% chances are the problem is with the hydroponic pH. The pH of the nutrient solution directly impacts the nutrient absorption rate of hydroponic systems.

You should measure the pH of the solution with a pH measuring kit every day. The pH kit has a pH scale in it. The scale starts from 0 and ends at 14. pH reading below 7 means the solution is acidic. Above 7 means the solution is alkaline. And 7 pH is the neutral value, this means the solution is neither acidic nor alkaline. It is a balanced solution.

pH 5 is more acidic than 6 and 9pH is more alkaline than 8ph.

In this article you’ll learn why the nutrient pH is changing and how does it impact the hydroponic systems. What you can do to keep your system healthy and how to adjust pH?

First of all, we will start from the basic knowledge

Every plant on the earth grows in a different environment and has different growing needs. You cannot grow warm crops in the winter season.


You will be surprised to know that their pH requirements are almost the same. Most of the plants need slightly acidic soil or water to grow. The ideal range is 5.5 to 6.5 pH. Whereas some plants can tolerate 5.0 to 7.5 pH.

Therefore. We can say that the ideal pH range for 97% of the plants is between 5.0 to 7.5.

If due to any reason the pH of the nutrient solution is outside the range. Then the plants become unable to absorb nutrients from the water. This results in slower growth and weak plants. In most cases, plants die in hydroponic systems due to disturbed pH levels.

If the hydroponic pH is below 5.5 then the plants start suffering from a lack of calcium. Calcium is necessary for the good health of plant roots.

If pH drops below 4.0 then the chances are your plant will get killed by Aluminum and manganese toxicity.

On the other side, if the pH goes above 7.0 or 7.5. Then the plants become able to produce enough chlorophyll and they also start losing their green color. Because the higher pH reduces the absorption amount of Iron, Phosphorous, and Manganese.

Insufficient chlorophyll means not sufficient food for the plants. They start dying slowly due to no more food.


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How to measure the hydroponic pH?

Hydroponic pH can be easily measured by 3 different methods.

Litmus paper

Liquid pH kits

Digital pH meter

Litmus paper method

This is the old technique of measuring pH. Most of us know how to use litmus paper. We all did a litmus paper experiment in our science lab.

Note: Blue litmus turns red when dipped in acidic solution.

In this method, dip the single strip of paper in the hydroponic nutrient solution. We left it for 30 seconds and it changes its color.

In the next step, we held it against the pH chart and determine the reading. This method is not good for measuring hydroponic pH. It is good to teach kids in schools.

Liquid kits

These kits are a little expensive than the litmus paper. First of all, we take a sample of the solution in the test tube. Then add few drops of the liquid tester. The solution changes its colour. We match the color with the pH chat. In this method reading the chart with color is easier than the litmus paper method.

Digital meters

These are the expensive pH measuring meters. If you have a hydroponic system then you should definitely invest in a digital pH meter. There is an electrode attached to the meter. You need to turn the meter ON and dip the electrode in the solution. It will tell you the digital reading on its display in less than 20 seconds.

You should buy an extra electrode in case the first one breakdown. You can reuse digital hydroponic pH meters as many times as you want. This makes them economical even after having a high price.

litmus papaer test

How to adjust the pH of the hydroponic solution?

You need to measure the Hydroponic pH every day specially if you are growing expensive crops. When the plants absorb nutrients from the water. They do not absorb all the nutrients in equal amounts. Sometimes they need more nitrogen than Phosphorous. This leaves the empty ion which disturbs the pH of the solution

To adjust it you should use pH UP and pH DOWN.

Read the instructions written on the bottles. Because every brand has a different concentration of the solution and has instructions accordingly. There is no specific brand better than others. Buy which is in your budget.

Note: If you are using hard water in your hydroponic machine then do not use ordinary pH adjusters. They are made for soft water. Hard water needs a high amount of acid to adjust the pH. This disturbs the nutrient percentage of the solutions.

For hard water always use pH adjuster solutions that are made for hard water.