How To Measure Ec In Hydroponics

by Lettuce Be | Last Updated: 07/14/2021

Hydroponic growers face numerous challenges when monitoring pH levels and nutrient solutions. Because some plants need very different ratios to grow full-size, we know this can impact each stage of growth.

In addition to these two factors, there is another aspect of nutrient solutions that requires constant monitoring and adjustment. Next, we’ll show you how the EC level affects your plants and how you can test it and adjust it if necessary.

Understanding EC Levels

ec measurement in hydroponicsThe EC measures a solution’s electrical conductivity. Another way to see it is CF, which stands for conductivity factor. These ECs are often written in conjunction with the pH levels of the hydroponic nutrient solution. You need to understand what those two terms mean at this point.

You can determine your nutrient balance by checking the pH levels in your mix. In contrast, EC is an excellent indicator of how much concentration of nutrients your solution contains. EC cannot exist in distilled water because it contains no mineral salts. Dissolved minerals and nutrient salts turn the solution into a conductor of electricity. As salt concentration increases, electrical conductivity or EC will increase.

EC levels are worth noting because it doesn’t tell you what nutrients, but it is an overall number of nutrient concentrations.

The Importance Of EC Levels in Hydroponics

The pH level in your hydroponic system varies according to the plants. The same is true for EC levels, and different plants prefer different levels. Moreover, most plants prefer an EC level between 1.2 and 1.6 as they grow and, once they reach flowering, they prefer one between 1.6 to 2.4.

Understanding why EC levels are vital requires us to understand what influences them. When these levels are measured in conjunction with pH levels alone, you get a detailed picture of what is going on in your nutrient solution.

Here is a brief overview:

EC Levels and Plant Growth

EC levels can affect the growth of plants, and a few factors can cause them to change. Follow these points to find out more. Besides how much nutrition plants absorb, several factors can influence these levels. These levels are significant for the reasons we have seen. As plants grow, here’s how it affects them.

A high EC level will burn seedlings, cuttings, and delicate plants. Having too high a level does not mean you have it wrong, as even a nutrient mix can be too strong for mature plants. To avoid plant damage from a nutrient burn, lower your nutrient levels to half strength during these stages.

Plants can be nutrient-concentrated once they are more substantial and in their vegetative growth stage. Your plant type still plays a role. Ideally, you should separate plant mixtures into light feeders, medium feeders, and heavy feeders. You will need three separate reservoirs if you have three different plants that feed at different rates.

It might seem overkill, and it may not match everyone’s hydroponic system, but it is an excellent example. You will end up with bitter lettuce if you feed it high EC levels suited to tomatoes. On the other hand, if you feed tomatoes with low EC levels intended for lettuce, then your tomatoes won’t have any taste.

Water Temperature and EC Levels

The temperature should be in an optimum range of 65 – 80 degrees Fahrenheit for nutrient solutions in your reservoir. Water temperatures must not change rapidly for plants to survive. Ideally, this should happen around the root zone. Ensure the regular water you add to your reservoir is at the same temperature as those already in the reservoir before adding it.

Your system will also be affected by the ambient temperature, so it depends on where you are. If you live in a colder climate, you might need an aquarium heater or a suitable chiller for your nutrient solution if you live in a warmer climate.

Air and EC Levels

Growing plants correctly requires airflow, as growers are well aware. However, many are unaware that ventilation plays a crucial role in EC levels.

There’s a difference between airflow and ventilation. The movement of air is called airflow, while ventilation is the removal of old air while introducing new air. The better the ventilation in your growing area, the higher the rate of transpiration will be. By doing so, plants can absorb and utilize nutrients more efficiently.

EC Management

By implementing an EC management plan, you enable your plants to adapt to changing conditions. Some growers improve their EC levels by utilizing low-light conditions. It helps counteract stretching by constraining vegetative growth.

Converting TDS and EC Values

It might seem complex again. Any value you choose to use will automatically be converted for you by your testing meter when you take readings. To find the approximate value of sodium chloride TDS in your solution, multiply your EC reading by 1000, and then divide by 2. If you want EC levels from TDS readings, you have to reverse the process. To calculate the ppm reading, multiply it by two, and then divide it by 1000. It is better to rely on a meter than converting manually.

EC vs. TDS

Different TDS meters produce mixed results when testing nutrient solutions in hydroponics. Several factors play into this, with some meter manufacturers using different calculations to arrive at their results. You should take TDS readings as you would any other reading for that matter and merely view them as approximations.
In these meters, the EC level is displayed using a conversion factor that uses an average ppm as the unit. There is an average 700:1 conversion ratio in most cases. As a result, if you have an EC of 1, then you have 700 ppm. These meters are manufactured by those who use 500:1 ratios which is a  huge difference.

In general, growers should use a 700:1 ratio because that is the safest and better for the plants. It is easier to add plant nutrients in water when they show signs of nutrient deficiency than to reduce the concentration to a weaker solution.

It is far better to keep things simple when considering nutrient strength in different stages of plant growth. When the plant is in its vegetative stage, use half-strength nutrient solutions, increasing its strength during the blooming and fruiting growth phases.
It should also be standard practice to empty and refill your reservoir regularly.

EC Meters

A test meter can be called many things. Truncheon meters, EC meters, and CF meters all fall into this category. All of these devices are essentially the same, but they may appear very different from the outside.

A digital EC meter can take readings and perform all calculations inside the unit. On the other hand, the truncheon meter has three scales that show the level of the reading. When the mark stops, you have the three levels.

New growers are better off with digital meters. However, though they are faster to use, a Truncheon meter is more expensive than a digital meter. We need to take EC readings daily because things can change quickly, and the weather and ambient temperature can play a significant role in these changes.

Organic Fertilizers and EC Levels

While reading EC levels is very beneficial for hydroponics systems, the results can become extremely misleading when organic fertilizer is used. Organic fertilizers do not conduct electricity because their molecules do not conduct electricity. Growers are still advised to take EC readings to determine the number of nutrient salts in their crop.

However, due to the form in which these nutrients exist, you won’t measure them via EC. The majority of them won’t have been reduced to simple salts. In cases where EC meters are used, the measured results will probably be significantly higher than non-organic fertilizers.

Although readings are lower, growers find that their plants show no signs of deficiencies despite the lower readings. Therefore, organic fertilizers must be used with alterations to the level of nutrients.
It is known that calcium tends to be deficient and can be around 100 ppm, which is a long way from the 200 ppm recommended for leafy green vegetables. These leafy greens don’t show any signs of calcium deficiency, as the calcium level is half of the suggested amount. Adding calcium sulfate helps remedy this issue.

When organic fertilizers are used, calcium and magnesium deficiencies are found, but these can be corrected with tap water. Pure water or de-mineralized water, on the other hand, does not help.

The calcium and magnesium levels in your hydroponic reservoir naturally increase over long periods (over several months) and can almost reach the recommended 200 parts per million. It is also possible for magnesium levels to increase naturally over time.
With organic fertilizers, it has been discovered that the smaller the reservoir, the more frequent the testing must be.


It’s easy to test for and adjust EC levels and pH levels, which are on paper hard to control. Learning more about hydroponic EC levels is a much better approach than ignoring it. You will notice this when you experience symptoms like nutrient burn, nutrient toxicity, or when your vegetables begin to taste bland.

It’s best to remember all the formulas, but with a digital meter to take the readings, the adjustment of your EC levels is nothing more than dilution. You can easily adjust your EC levels so that your plants can achieve their full potential as long as you keep them on the right side of the spectrum.

Managing pH levels and nutrient solution amounts can be a challenge for hydroponically grown plants. Plant growth can be affected by this because some plants require very different ratios to grow fully.

Nutrient management is made more challenging by another element that requires constant monitoring and adjusting when needed. As we shall see, EC level has a profound effect on your plants, and here we will see how it can be tested and how it can be adjusted if necessary.