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3 tips for measuring and adjusting pH

pH and ec meter

Written by Jaap Lubbersen | Last update: 30-11-2020

Fertilization advice is often precisely calculated to the millimol. This requires a very precise methodology in the application of fertilizers. The crop pH here is of crucial importance because a pH that is too high or too low results in a reduced absorption of certain nutrients. For that reason we’ll list a few important items concerning pH.


Choice of chelate for measuring and adjusting ph

Choosing the appropriate type of chelate plays an important role in the soil’s or substrate’s pH level: a DTPA chelate has already lost part of its effect at a pH of 6.5, while this only happens to a EDDHA-chelate at a pH of 8 or higher. Take this into account when choosing a chelate.


Preparation of fertilizer containers 

The wrong pH level in the fertilizer container can cause flocculation and sediment of your fertilizers and/or trace elements. This can clog your fertilizer container. There are extensive charts available that show the proper pH level for each fertilizer or chelate. The following rule of thumb is often sufficient: e pH level between 3.5 and 5 is always good, regardless of which iron or fertilizer is used.

Supplies for adjusting ph

Measuring and adjusting pH

Always measure pH levels after adding fertilizers to the fertilizer container. Ensure you have a properly functioning pH meter and calibrate it regularly. Practice shows that some (expensive) meters are replaced after a couple of years of faithful service because they don’t work well any longer. Replacing the measuring probe and calibration with a new set of calibration bottles is however often enough for the pH meter to work properly again.

Adjusting pH levels in the fertilizer container can be difficult and requires precise work. Nitric acid can lower pH levels, caustic potash raises the pH. Ensure that you are using the appropriate safety measures when using these materials (safety goggles and gloves)



More information about recognizing and controlling Pythium

Do you have any questions about measuring and adjusting pH, or would you like advice? Then contact one of our specialists, or ask your question using the form below. We'll respond within 24 hours on working days.

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Choice of chelate

Jaap Lubbersen About Jaap Lubbersen

Jaap Lubbersen is an internal crop care product specialist at Royal Brinkman and has had over 13 years of experience in glass horticulture. "As an internal product specialist, I deal with growers' issues on a daily basis. Every time again it is a challenge to seek the proper solution, in cooperation with the grower, whether it is about healthy and vibrant cultivation, legislation or safety."





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