EC is a measure of the electrical resistance of water, nutrient solution or effluent from a growing media. EC is used to determine the level of ions (salts) in a media which has a direct effect on the growth of a plant. The units of EC are millimhos per centimeter (mmhos/cm) or decisiemens per meter (dS/m). High EC in any growing media makes it harder for roots to take up water and nutrients introduced to the growing media. High EC can result in damage ("burn") to root tips and toxicity or burn symptoms in foliage.
EC of a nutrient solution as well as that of the growing media can significantly affect plant growth. EC measurements of the nutrient solution will tell you whether to replenish more nutrients into the water or to remove ("leach out") excess build up of undesirable salts from the media or nutrient solution.
EC should be below 3 mmhos/cm, with an ideal target level of 2 mmhos/cm. If the EC is above 3 mmhos/cm, then it is time to leach out the accumulated salts using water. If the EC is below 1.5 mmhos/cm, then it may be time to add nutrients to your irrigation water.
EC metering equipment is quite affordable and readily available.
SteadyGROWpro is not high in salts and will not adversely affect EC.
Sources: Pawan Srivastava, PhD
