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Measuring pH and EC levels

pH and EC levels within the substrates are highly important for optimal plant growth. In this article we cover what these values tell you and how to measure them correctly yourself.

Before we show you more about measuring pH and EC levels, it’s important to know why you should be aware of them.

What does the pH value tell you?

The acidity of a substance is measured in pH. This scale reaches from -7 to +7, with 0 being the neutral level. Different crops prefer different levels of acidity in the substrate and irrigation water. When the pH is on the right level plants will show better growth and rooting. That’s why it’s important to check the pH in the substrate at your facilities.

What does the EC value tell you?

The EC level indicates how much salts are dissolved in the water, thus indicating the availability of nutrients to the plants. Would you like to know more about plant nutrients? Have a look at this related article.

Methods of measurement

There are many different methods to measure the pH and EC levels. However, different methods of measurement can also result in different outcomes for the same materials. That explains why it is important to know which method is used to get the values, so they can be compared in a correct way.

The diversification of methods, by laboratory and country, used to create confusion in the interpretation of results in the European Union in the past. To support trade and to avoid confusion the CEN (European Committee for Standardization) Technical Committee 223 Soil improvers and growing media has published standards for the determination of pH (EN 13037:2011) and EC (EN 13038:2011) in a suspension of soil improvers or growing media.

As Kekkilä-BVB is a European company and Kekkilä Professional is a European brand we are under the regulations of the European Union. That’s why we declare pH and EC values based on European standard method of measurement: the 1+5 method in distilled water. This means 1 volume of substrate is diluted into 5 volumes of distilled water.

How to measure pH and EC levels yourself

Follow the steps below to correctly measure pH and EC values in the substrates you use at you sites, using different methods.
We’ve also created some videos to visually support you and show you the best ways to do it!

Method 1: 1+5 method for fine and medium coarse products

1. Take 1L of substrate (200g)
2. Measure out 1/10th of the sample (20g)
3. Add 5dL of distilled water to the sample
4. Stir thoroughly
5. Wait 30 minutes
6. Use pH and EC measurement kit to measure values (make sure to follow kit instructions)

Method 2: Press water method

1. Take 1L of substrate and weigh it
2. Add distilled water untill the total weight is 550g
3. Stir thoroughly
4. Wait 24 hours
5. Push the mixture through a filter to filter out the liquid sample
6. Use pH and EC measurement kit to measure values (make sure to follow kit instructions)

Method 3: Squeeze method

1. Irrigate/fertigate as usual
2. Wait for at least 1 hour
3. Take a potted plant and collect liquid samples from near the root zone by squeezing
4. Repeat this with multiple plants to make sure your sample is representative
5. Use pH and EC measurement kit to measure values (make sure to follow kit instructions)
Note: When using this method regularly it’s important to make sure to have a similar time span between irrigation and sample collecting every time.

Contact your distributor if you’d like to know more about pH and EC levels.