EC Nutrientes na Água

EC: nutrient concentration in water

Electrical Conductivity (EC) tells you how many dissolved mineral salts are in the water, read in mS/cm (millisiemens per centimetre). The more ions in solution, the higher the conductivity, and the more nutrients the roots can take up. Ranges differ from crop to crop. Lettuce sits around 0.8–1.2 mS/cm, tomato wants 2.0–2.5 mS/cm, and strawberry falls in between at 1.4–2.0 mS/cm. When it comes to hydroponic nutrient formulas, the old Hoagland solution (1933) is still the reference everyone goes back to. You can also turn EC into TDS (Total Dissolved Solids) with TDS (ppm) = EC × 500 to 700, where the multiplier depends on how your meter is calibrated (NaCl, 442 or KCl scale). Don't lose sight of pH 5.5–6.5 either. Drift outside that window and several micronutrients (Fe, Mn, Zn) precipitate out and stop being available, no matter how good the EC number looks.

Applications

Watching EC matters wherever water carries the nutrients. That covers commercial and home hydroponics, fertigation in greenhouses and open fields where drip lines dose fertilizer on the fly, aquaponics that pairs fish with plants (fish tolerate EC up to about 3 mS/cm), and precision agriculture running in-line EC sensors that trigger automatic dosing pumps. Skip the meter and you're growing in the dark.

FAQ

Why does EC vary by crop? Leafy greens such as lettuce pull nutrients efficiently even at low concentration. Tomato and pepper, on the other hand, need a higher osmotic pressure before they reward you with sweetness and yield. Push EC too high and you stress the roots and scorch the tips.

What's the difference between EC and TDS? EC is a direct reading of conductivity. TDS estimates the mass of dissolved salts by applying a conversion factor (0.5 to 0.7) to that reading. Either way you get a sense of concentration, but EC is what the probe actually measures.

Why monitor pH together with EC? Even when EC is spot on, a pH outside 5.5–6.5 locks out Fe, Mn, Zn and Ca, and the deficiency soon shows on the leaves. Read both every day.