Nutrient Control

The strength of a nutrient solution is measured by its electrical conductivity (EC) and is of critical importance. Too high an EC results in vegetative growth at the expense of fruit or flower production and too low EC produces weak unproductive plants.

CF or EC is simply a measure of electrical conductivity through the nutrient; the more nutrient elements present in the water gives a higher CF or EC reading and vice versa.

When growing using active systems nutrient strength should be monitored, normally at the same time as the pH is checked.

pH (or potential of hydrogen) is a measure of how alkaline or acidic the nutrient solution is. The pH scale runs from 0 to 14, with 0 - 7 being acidic and 7 - 14 being alkaline. pH 7 is neutral, being neither acid or alkaline.

The majority of plants prefer the ph between 5.5 and 7.5, beyond this range some nutrient elements will be unavailable to the plants, the optimum pH being between 5.8 and 6.3. Most tap waters are between pH 7 and 8.

Monitoring the pH is essential to ensure that the plants have the optimum nutrient mix available to them.

pH & EC Meters

A pH meter is an electronic instrument used to measure the pH (acidity or alkalinity) of a nutrient soltion. A typical pH meter consists of a special measuring probe (a glass electrode) connected to an electronic meter that measures and displays the pH reading. An EC meter measures the electrical conductivity in a solution. They are used in hydroponics to monitor the amount of nutrient salts in the water.

pH Control Solution

There are various products used in hydroponics to adjust pH. The most popular are probably phosphoric acid (to lower pH), and potassium hydroxide (to raise pH).

pH Control Solution