Hydroponics: pH value and EC value

Hydroponics has experienced rapid development and increasing importance in recent decades. The requirements for defect-free and damage-free appearance of hydroponic plants are also of particular interest.

The main requirements in hydroponics are the pH and EC measurements, which are very specific for the plants. Therefore, it is also mandatory to comply with them so that deficiency symptoms and damage can be avoided.

The acidity (pH) of the water affects the availability of nutrients to plants. In a pH range of 5.5 – 6.5, a wide variety of nutrients can generally be best absorbed by the roots, regardless of the cultivation method.


The EC value indicates the electronic conductivity of a solution. This also provides information about the amount of dissolved salts and nutrients. Nutrients break down into positive and negative ions, and ions conduct electricity.

Accordingly, the more nutrients that exist in the nutrient solution, the more conductive it is. Some plants prefer a high nutrient concentration and some a low one.

Special care is required here: Too many nutrients have a toxic effect, too few nutrients result in deficiency symptoms in the plants. Only the maintenance of the specific pH and EC values of the plants allows a healthy hydroponic plant.

Representative pH and EC values are excellently described in various literature works for both crops and ornamentals in hydroponics.

For testing pH and EC values, Apera offers a wide range of measuring instruments for every application from private to professional use.