What Is EC and Why Does It Matter?
In hydroponics, EC (electrical conductivity) measures the strength of nutrients in your solution. Also referred to as CF (conductivity factor), EC helps growers understand the total quantity of dissolved salts, which are the mineral nutrients your plants absorb.
Whereas checking your pH levels tells you about the balance of available nutrients, EC tells you how much is available.
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Pure water has no EC because it contains no minerals.
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The more salts (nutrients) added, the higher the EC reading.
Target EC ranges vary:
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Vegetative stage: 1.2–1.6
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Flowering stage: 1.6–2.4
Why Is EC Important in Hydroponics?
Regularly monitoring EC gives you deep insight into what your plants are absorbing. Based on how your EC levels fluctuate, you can adjust your nutrient mix:
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If EC stays the same: Your plants are absorbing nutrients and water evenly. Maintain the same strength.
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If EC drops: Plants are absorbing more nutrients than water. Top up your solution and consider increasing concentration slightly.
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If EC rises: Plants are absorbing more water than nutrients. Dilute your feed with water to avoid nutrient burn.
Signs of overfeeding include burned leaf tips and slowed growth, especially during hot weather when water uptake increases.
How to Measure EC
The easiest method is with a digital EC meter like the Bluelab CF Truncheon. Simply dip the probe into your nutrient solution and read the display.
For reliable results, test daily—conditions can shift quickly in hydroponics. Regular calibration is vital to accuracy, so use the Growth Technology Conductivity Standard and Bluelab EC Probe Care Kit for maintenance.
Visit any Holland Horticulture store for a free EC meter calibration service.
Don’t Just Top Up—Flush Weekly
If you continuously top up without replacing the solution, you risk toxic nutrient imbalances.
While EC measures the total amount of nutrients, it doesn’t show how much of each type is present or whether any harmful salts or waste have built up.
Perform a full reservoir change every 7 days and create a fresh solution to maintain peak plant health.
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For more help optimising your hydroponic nutrient strategy, speak to a specialist in-store or by phone. We're here to help your plants thrive!