EC And Hydroponic Nutrient Solutions
As mentioned earlier, we also need to measure the electrical conductivity (EC) of our nutrient solution for hydroponics.
You can measure the concentrations of fertilizer within your water (together making nutrient solutions) by its ability to conduct electricity. Pure water does not conduct electricity, however solids do. The more fertilizer you add to your water, the more it will conduct electrical currents.
Therefore your EC readings will give you an exact idea of the overall strength or concentration of the dissolved solids or fertilizer within your solution. The more fertilizer you add to your water, the higher the EC reading will climb.
Again, as with measuring pH, EC readings are temperature sensitive. So it’s a good idea to take both EC readings and pH at the same time every day. You can get some electrical devices that measure both EC and pH simultaneously, so this will be a time saver. A good quality electrical EC/pH reader can last many years provided you look after it. This includes keeping the metal probes moist.
This next part is very important. Since plants, hydroponic plants in particular use lots of water, you’ll need to be making lots of little adjustments and top ups to your hydroponic nutrient solution. Clearly, as you add fertilizer, up or down solution or water to your existing hydroponic nutrient solutions, your EC readings are going to increase or decrease proportionately. When checking your nutrient solutions EC readings, it’s best to have it between 500 and 2000 PPM. However, the vast majority of plants will thrive best with those numbers narrowed a little more. For the best results, you should be aiming for readings between 800 and 1200 PPM. As you make your daily or thrice weekly adjustments to your hydroponic nutrient solution, your PPM is going to increase or decrease away from these preferred ranges. For this reason and for a few other reasons, it is best to completely change your hydroponics nutrient solution every two weeks.