Electrical Conductivity (EC) is one of the most important factors for the success of any hydroponic system. Measuring and controlling this parameter correctly can make all the difference between healthy, productive plants and stressed plants with poor performance.

In this article, you will learn what EC is, why it’s so important, how to measure it correctly, and the ideal values for different crops.

✅ What is Electrical Conductivity (EC)?

Electrical conductivity (EC) indicates a solution’s ability to conduct electricity. In hydroponics, this value reflects the amount of dissolved salts in the water, meaning the concentration of nutrients available to your plants.

• The higher the salt concentration, the higher the EC value.

• If EC is too low, the plant may suffer from nutrient deficiency.

• If EC is too high, there can be toxicity, osmotic stress, and even nutrient uptake blockage.

  ---

📏 How to measure EC

EC is measured with a digital EC or TDS meter, and can be expressed in:

• mS/cm (millisiemens per centimeter): most common in hydroponics

• μS/cm (microsiemens per centimeter): 1 mS/cm = 1000 μS/cm

• ppm (parts per million): common in TDS meters; conversion depends on the device factor (0.5 or 0.7)

🎯 Tip: Always use the same type of meter and calibrate it regularly to ensure accuracy.

📊 Recommended EC values by crop

⚠️ Values may vary depending on plant stage, climate, and system type.

🧪 How often should I measure EC?

It’s ideal to measure EC daily, especially in recirculating systems. Changes in weather or plant water consumption can quickly alter the nutrient balance.

• Early in the day: for a reliable baseline

• After adding nutrients or water: to adjust correctly

• When changing the reservoir solution: record and make necessary adjustments

  ---

🚨 What happens if EC is incorrect?

Low EC (nutrient deficiency):

• Slow growth

• Yellow or pale leaves

• Weak plant structure

High EC (excess nutrients):

• Leaf burn at edges

• Wilting or stress

• Nutrient uptake blockage (toxicity)

  ---

💡 Practical tips for effective EC control

• Calibrate your EC meter weekly with standard solution

• Use good-quality water with low EC (preferably < 0.4 mS/cm)

• Record daily EC, pH, and water temperature

• Adjust EC gradually to avoid stressing plants

• Replace the nutrient solution every 1–2 weeks to prevent salt buildup

🧰 Recommended equipment

• Portable digital EC/TDS meter, accurate and easy to use

• Calibration solution to maintain meter precision

• Water thermometer, since temperature affects EC

• Clean, graduated containers for correct solution preparation

  ---

🌿 Summary

Controlling electrical conductivity precisely is essential for successful hydroponic crops. Monitoring EC helps you:

• Ensure balanced nutrition

• Avoid deficiencies and toxicity

• Improve growth and productivity

• Reduce water and nutrient waste

At ToDo Hydro, we provide not only high-quality systems, but also the knowledge you need to grow safely and successfully.