Best hydroponic pH level

Maintaining the Best hydroponic pH level in Hydroponic systems is key to get success in soilless growing. If do not understand the concept of pH level in Hydroponics and you are unable to adjust it then continue reading this post till the end.

Today you will learn every important thing about Hydroponic pH level that leads to success.

What is pH?

pH stands for Potential of Hydrogen in Solution. You need to measure the pH of the nutrient solution to know about its nature. A solution can be acidic, neutral, and alkaline. The pH scale starts from zero and goes to 14. As shown in the figure below

pH scale hydroponics

pH 7 means your solution has a balance of positive and negative ions and is a perfect solution. Only pure water has a neutral pH level.

Example: If your solution has a pH of 6.5. it means it is slightly acidic. 5 pH means more acidic than 6.5 pH Solution.

As the pH of the solution goes from 7 to 0 it indicates that the acidity of a solution is increasing.

Example2: pH going above the 7 means solution is becoming more alkaline. pH 14 means the solution is extremely alkaline.

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Best Hydroponic pH level and Absorption of Nutrients

The pH of the solution decides the solubility, availability, and nutrient uptake rate. In simple words, every nutrient that you mix into the water to form a perfect food for your plant reacts differently to the hydrogen ions present in the water. This disturbs the pH level of water and you need to readjust it for your growing plants.

For example: If the pH level of the nutrient solution goes higher than 7 your plant became IRON and CALCIUM deficient even if these nutrients are present in a sufficient amount. Because High pH makes Calcium and Iron less soluble in water and you will see a white color substance on the reservoir walls.

So, you need to maintain the best hydroponic pH level in your hydroponic systems to grow better plants. So that the plant roots can easily absorb the macro and micronutrients and transfer them to different parts of the plant.

If the pH comes below 5.0 your plants became unable to uptake even a single part of the nutrient. This condition is called a complete block of nutrients.

It is best to use water that you drink to prepare the nutrient solution for your plants.


Let’s say the pH of your water is close to 7 (6.7 pH). Mix the nutrients in it and leave the solution for 30 minutes. Because the nutrients are on the acidic side and they drop the pH level of the solution to the acidic side of the pH scale.

After then you need to measure the reading, again, assume that at this point you get a 6 to 6.5 pH reading. Put this solution to the water reservoir and let it circulate completely in the system.

Because plants are selective to certain nutrients, means plants take some nutrients more than others. This also decreases the pH levels.

If you are using the systems with 20 gallons of water storage capacity. You need to wait for another 30 minutes. After then check the pH again and this is the reading you need to adjust.

Assume at this time your nutrient pH reading is 5 or 4.8.

Here you need to increase the pH level and for that, you need to choose the professional products like

What is the best Hydroponic pH level for the hydroponic nutrient solution?

Every nutrient reacts differently in water and when you combine many of them you may get a highly acidic solution or vice versa.

The best-recommended range of pH for indoor hydroponic nutrient solutions is between 5.5 to 6.5 with a slight fluctuation of 0.5.

So now it is clear that you need to maintain the pH of your hydroponic nutrient solution between 5.5 to 6.5. Little fluctuation in the reading is not a problem but try to keep the pH between the recommended range.

How to manage the pH in hydroponics?

First of all, you need to have a tool to measure the pH. You can do the old-school litmus paper test to measure it but this formula does not give an accurate reading. Most of the time you will find it difficult to match the color of the strip to the given chart.

The best method is to buy a pH meter from Amazon and use it. Your local stores will cost you more than the online price.

Once you have the pH meter at home read the instruction to calibrate it by using the solution given by the pH meter manufacturer.

The first step is taking the pH reading of your tap water in which you are going to add nutrients. If the tap water shows a reading of 5 or 5.5 you need to leave it and choose the filtered water.

General hydroponics up and down solution

general hydroponics pH kit

Do not use household products like some people use sodium bicarbonate to down the pH. This is an unprofessional way and this can damage your plants as well as the growing system. Plants do not need sodium bicarbonate and other unnecessary substances.

Use General Hydroponics pH UP and Down solutions To maintain the best hydroponic pH level. Because this kit does not interfere with other nutrients present in the reservoir.

If you are using the hydroponics system with a total water holding capacity of fewer than 30 gallons then a one-gallon bottle of pH up will last more than 1 year.

I have a 300-gallon reservoir and 1 gallon of pH adjusting solution lats for 4 months. I need to mix it in a low quantity (half cup).

For 30-gallon systems, you need to mix a tablespoon of it and it makes your pH level stable for a long time.

Do not get panic if you see frequent changes in pH. It indicates that your plant is growing fine and is absorbing nutrients from the solution. Once the frequent fluctuation stops than take the final reading and adjust pH.

(If you get many different readings in the first hours don’t worry it is normal.)

Why the pH of the hydroponic nutrient solution changes once it gets corrected by Grower?

A number of reasons is responsible for the ups and downs in pH levels. The main cause of these ups and downs is the water and nutrient absorption by the growing plant. This makes it extremely important to keep eye on pH level in hydroponics especially if you just add some new plants to your system.

New plants always demand a high amount of nutrients and they drink water and nutrients rapidly. once your plant reaches its appropriate height then you observe fewer changes in pH. Because at this level plants absorb fewer nutrients because they are not growing in size anymore. Just to produce fruit, plants need fewer nutrients.

pH also decreases at a faster rate if you keep the reservoir less than half-filled. So make sure you have a sufficient gallon of solution for each plant.

Another factor that can disturb your pH reading is the use of growing medium like rockwool, river rock, etc without neutralizing them.

Always neutralize these inorganic growing mediums before use. Take the water with 7 pH or adjust it (you know how to adjust pH, use the same solution) soak them into it for 1 to 2 hours to make them neutral. If required change the water twice or thrice. Manmade growing mediums disturb the pH level if they do not get neutralized before use in hydroponics.

Another common cause of changing the pH of your nutrient solution is a build-up of algae and bacteria in your growing system. This is a result of improper care and cleaning.

How frequently you need to check the pH?

If you are a beginner then you need to check it every day until you get some experience in preparing the nutrient solutions.

Once you learn enough about plant nutrients then you can easily maintain the best hydroponic pH level of the system.

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