Controlling Hydroponic Nutrient Solution Strength

by Simon Ware

Hi, I am very new to hydroponics and having trouble finding information on EC control that I can make any sense of. Can you possibly explain it in basic terms and give any relevant information you feel will help me.

Thanks for your time,
Simon Ware

Answer Simon- EC stands for electrical conductivity. Just like your nutrient solution has a certain temperature, your nutrient solution also has a certain strength (depending on how much fertilizer is in the solution). With temperature, the scale you would use to measure it would be either Fahrenheit (F) or Celsius (C). With nutrient solution strength, the scale you would use to measure it would be either electrical conductivity (EC) or total dissolved salts (TDS).

Different plants prefer slightly different growing conditions. Your first step to success will be to find out what the nutritional requirements are for the plants you are growing. This is often called a feeding plan. The feeding plan will tell you what nutrient strength you should be feeding your plants each week, what pH your plants prefer, and whether the fertilizer should be high Nitrogen (for veg) or high Phosphorus (for flowering).

For example, let's say you are growing tomatoes. You decide you want to grow them for 3 weeks before you fruit them, and the variety you chose takes 8 weeks to finish flowering. Tomatoes will do fine at a pH of 6.0, and the rest of the feeding plan may look something like this....

                    

The nutrients you purchase will probably come in two or three parts, and should include directions on how to mix up vegetative fertilizer as opposed to flowering (bloom) fertilizer. Your feeding plan tells you how strong your nutrient solution needs to be, and what pH it needs to be at. Once you know these numbers, it becomes very easy to maintain your nutrient solution properly....for more info on that, visit my how to grow hydro page.

As the link above describes, controlling your EC starts with knowing in advance what your nutrient solution strength SHOULD be....than you simply check the nutrient solution at least once a day with your EC meter (or TDS meter) and make the proper adjustments. If the solution is too strong, add a little bit of plain water (and test the solution again). If it is too weak, add some more nutrients (and check the solution again).

I hope this sheds some light on the subject for you, and be sure to check out the link I included above....it will complete your understanding of the topic. Happy Growing!