How to Keep the PH Level of Each Hydroponic Growing Medium?

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Hydroponics is the art of growing plants without soil by using minerals, water, and other substances to supply nutrients.

Hydroponic growers use various mediums for their plant’s root systems to grow in.

The pH level of each hydroponic growing medium varies depending on the goal for that particular type.

This article will go over pH levels and tips on maintaining pH levels within a desirable range.

What Is pH?

pH is a measure of the acidity or alkalinity of a solution. pH is measured on a scale from 0 to 14, with seven(7) being neutral. A pH level below 7 indicates an acidic solution and above 7 indicates an alkaline solution.

The colors of pH levels are shown below.

colors of ph levels

Why Do pH Levels Matter in Hydroponics?

The pH levels of a hydroponic growing medium will have different effects on the plants. In general, a pH level that is too low or too high will make it difficult for the plant to absorb nutrients. This can cause the plant to be stunted in its growth or even die.

Usually, preferred pH ranges are given with hydroponics supplements.

The pH of Each Hydroponic Growing Medium.

Each hydroponic growing medium has a different optimal pH range that should be maintained to achieve desired results.

Referring to the available resourcesThe most common pH levels for each medium are as follows. However, I advise your to look into the instructions provided by the manufacturer or supplier before using it:

  • Mineral wool — Basic
  • Coconut fiber — Neutral
  • Expanded clay — Neutral
  • Perlite — Neutral
  • Vermiculite — Basic
  • Oasis cubes — Neutral
  • Sand — Neutral
  • Peat — Acidic
  • Grow stones — Basic
  • Rice hulls — Neutral/Acidic
  • Pine bark — Acidic
  • Pumice — Neutral
  • Sawdust — Acidic
  • Polyurethane — Neutral
  • Gravel — Basic
  • Expanded shale — Neutral
  • Lava rock — Neutral


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How Do I Know if My Plants Need More or Less Nutrients in Hydroponics?

It can vary, but in general, one way to tell if your plants need more or less nutrients in Hydroponics is by comparing their actual growing conditions.

For example, a lack of nutrients will lead to yellowing the leaves and vegetation, while too much will lead to browning.

Another thing you can do is examine the root system with a magnifying glass. If you see tiny holes on the roots that look like tiny cuts or scratches, then this means they are getting plenty of water and have plenty of oxygen.

On the other hand, if there is moss overgrowth on top of the root ball when the plant has a high nutrient solution for a prolonged period, they may not be getting enough nutrients/water/oxygen.

What Is the Best Way to Maintain pH Levels in Hydroponics?

The pH meter would be a good solution to maintain pH levels in Hydroponics.

This tool will help you test and adjust your solution’s pH level until it is within the desired range.

It is advisable to use distilled or purified water because tap water may have its pH level.

If your hydroponics system does not allow this, then make sure to use the correct type of nutrients according to the instructions based on your growing medium’s desired pH range.

You may need to buy a pH meter. Nowadays you can use pH test kitspH meters or pH/TDS/EC/Temperature meters. Click the links and select the best one perfect for your needs.

How to Maintain a Desirable pH Level in the Hydroponic Growing Medium?

The most common way of maintaining the pH levels of your Hydroponics growing medium is to use nutrient solutions that will buffer the solution and keep it within the desired range.

If you are using natural growing media, then the pH of your water will also affect the pH level of your growing medium. You may need to adjust the pH levels of your water depending on what type of medium you are using.

If the pH level of the hydroponic medium is high, you can add a small amount of vinegar to the water to lower the pH level.

If your growing medium’s pH level is too low, you can add limewater or kalkwasser to raise its pH. Kalkwater contains calcium carbonate, which will convert into calcium bicarbonate when introduced to a high pH level. This will help to increase the pH of your medium.


Maintaining the pH level of your hydroponic growing medium is important for healthy plant growth.

In this article, I’ve given you a few tips on maintaining a desirable pH level in your medium using different methods.

If you are using a hydroponic arrangement that does not allow for pH adjustment, then make sure to use the correct type of nutrients according to the instructions based on your growing medium’s desired pH range.

Thank you for reading!

Related: 10 Characteristics of Ideal Hydroponic Growing Medium

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