EC Electric Conductivity
The EC (Electric Conductivity) is an important measure of total solute concentration (salinity level) of a solution. High salinity in the solution decreases the availability of water to the roots of plants and prevent nutrient uptake and overall growth performance.
The osmotic potential near the root, which depends on the nutrient concentration in the solution, is used to control the plant's growth, development and fruit quality.
The EC can be completely controlled by the Gardener. Commercial growers make daily decisions about their EC settings depending on the condition of the crop and on light levels. A good understanding of EC level is essential for maximum crop performance.
Pure water does not conduct electricity. As you dissolve salts in water, you increase the Electrical Conductivity. It is the salts that conduct the electric current. Solution with a high concentration of salts have a high Conductivity rate.
Testing EC level
Gardener's can easily determine the EC of a solution using an EC meter.
This article courtesy of www.hydroponicsearch.com