Measuring EC: why pH matters too
The EC value indicates how well water conducts electricity. Together with a pH reading, it helps you assess nutrient solution. Learn what each number tells you, how to compare readings and which order to follow.
Written by Kyano Digital
What does EC mean?
EC stands for electrical conductivity. Dissolved salts affect the reading, including substances in your source water and added mineral nutrients. The number does not identify individual nutrients. A higher reading therefore does not automatically mean that your plants are better fed.
What does pH add?
pH describes how acidic or alkaline a solution is. This affects nutrient availability. Even a suitable nutrient concentration can be poorly available when the acidity does not suit the crop and growing medium. EC and pH answer different questions and should be considered together.
Measure the source water first
Use clean equipment and check your instrument according to its manual. Measure the water before adding nutrients. Record the reading and temperature. This shows the contribution of the source water and makes later comparisons more useful.
Check EC before adjusting pH
Add nutrients according to the feeding schedule and mix thoroughly. Check the EC of the mixed solution and assess the concentration for the crop and growth stage. Then measure pH and adjust it if needed, following the product instructions. Mix again and check the finished solution before use.
Use consistent units and methods
Conductivity can be displayed in mS/cm or µS/cm. One mS/cm equals 1000 µS/cm. A ppm display uses a conversion factor that can differ between instruments. Prefer the original EC unit when comparing readings and record your method. A reservoir reading cannot be directly equated with a direct substrate measurement.
Which reading should you aim for?
There is no single ideal number for every crop and medium. Use the feeding schedule as a starting point and account for water quality, growth stage and measurement method. Do not immediately add more nutrients after an unexpected result. Check calibration, mixing and units, then repeat the measurement.
Make readings comparable
Record the date, source water, nutrients, EC and pH. Use the same method wherever possible. A sequence of comparable readings helps reveal changes. Rinse and store the sensor as specified by the manufacturer; a pH probe may need different storage from a conductivity sensor.
Explore our pH and EC meters.