Nowadays, hydroponics is considered one of the most promising new technologies, and not for nothing, as it can not only significantly reduce agriculture’s environmental impact but also the time spent on growing plants and increase the yield.
What is EC in hydroponics? With all this, any plant, no matter how it is grown, must be monitored. When hydroponic plants are weak, they can give us some unhealthy signs. However, to find out the cause of any problem, you need to know exactly what nutrient concentration the plant receives. And special devices, such as, for example, ES meter, will help to understand this.
In this article, I will tell you what this meter is and how to use it.
Contents
What is EC in hydroponics? What is hydroponics?
Let’s first figure out what hydroponics means.
The word itself comes from the Greek ‘ύδωρ’ meaning water and ‘πόνος’ meaning labor. In practical application, hydroponics is the cultivation of plants without the use of soil in a liquid nutrient solution enriched with nutrients.
The hydroponic system makes it possible to grow plants using a more efficient and effective way with less effort and more quickly.
Even though plants are grown without the use of soil, there might be some kind of substrate like coconut coir, rock wool, or expanded clay. Since the plant does not need soil for growth, but the composition of macro- and microelements that it contains, it is important to maintain the proper level of these very elements.
It is here that we encounter EC (electrical conductivity).
Electrical conductivity
In a hydroponic system, all nutrients are obtained from mineral salts dissolved in water, so the nutrient solution strength is determined using EC measurements or CF (conductivity factor).
The higher the ion concentration (salt concentration), the higher the EC level, therefore the electrical conductivity can be seen as a reflection of the nutrient solution strength.
EC is measured in millisiemens per centimeter (ms/cm).
The conductivity factor won’t help you to establish the ratio between ions and won’t show the concentration of elements in the solution. EC can only indicate that there is a sufficient (or insufficient) amount of nutrients in the solution, it will also give a general overview of the content of the dissolved salts.
Crops EC
So what is the ideal range of hydroponic crops EC? It is between 0.5–1.5 ms/cm.
If the EC level is too high, plants won’t be able to get nutrients due to high osmotic pressure that can be caused by over-watering or under-watering. If the EC level is too low, it can lead to nutrient lockout (the roots can’t get nutrients due to a lack of mineral ions).
Despite having the ideal range of EC for hydroponic crops, it is worth noting that plants do not have the same optimum EC value. You may ask why? Well, the answer is simple. First of all, the need for a certain level of nutrients depends on the specific plant. So, the amount of nutrients in the nutrient solution impacts EC levels.
The other factor is the growth stage. For instance, seedlings, as they can burn easily, prefer lower EC values, while mature plants prefer a nutrient solution with a higher EC.
Environmental factors, like air temperature, are worth keeping in mind as well. It is better to start with a lower EC value when the weather heats up, increasing it until you see the results you want.
EC meter and its calibration
The health of plants depends on the nutrients they receive from a liquid nutrient solution. Depending on the system size and the type of plants, some amount of water will be lost leading to an increase in the EC values in a nutrient solution.
Therefore, it is important to measure EC every day.
Measurements are taken with an EC meter. Luckily, you can find various kinds of EC meters at different prices. Choosing an EC meter, try to look for those that are easy to use, shock- and waterproof, and easy to calibrate. Also, bear in mind, that cheap meters can be less accurate than more expensive ones.
When you start using your EC meter for the first time, you need to calibrate it to get accurate readings, otherwise, you won’t be able to monitor the nutrient levels.
There are two ways to calibrate EC meters correctly. They are manual and automatic calibration. Using the first way, you make manual adjustments of values until they meet a certain range. The automatic calibration suggests that the meter itself will correct any errors automatically.
Is ppm and EC the same?
As described above, the concentration of dissolved salts in a nutrient solution is measured by a device called an EC meter. However, besides EC meters, there are also TDS meters.
Both of them are similar and provide a measurement ofthe same physical property — solution conductivity, i.e., the capacity to conduct electricity, on which the concentration of salts in a nutrient solution is measured.
The only difference between them is that they measure the property in different units.
EC meter measures the electrical conductivity in standard units — millisiemens per centimeter (mS/cm) or micro siemens per centimeter (μS/cm). 1 mS/cm = 1000 μS/cm.
TDS meter (total dissolved solids) measures the EC at first and then converts it into another unit — ppm (parts per million). For instance, 200 ppm means 200 particles of a substance are capable of conducting electricity per million water particles in the nutrient solution.
So why use two different units for measuring the concentration?
The measuring equipment manufacturers in different countries originally preferred different metrics. It is EC in Europe and TDS in the USA and Australia. Both standards are still in demand, therefore, the global industry continues to produce devices of both types.
You can use the one you find more convenient. Meanwhile, it is better to get used to measuring in EC from the start because this metric is more practical, as it is consistent all over the world.
But when using a TDS meter, everything is not so simple, as this metric uses a different unit of measurement — ppm. And depending on the place the device was made, it can use one of three standards to convert from EC to ppm:
American standard (as a reference point, a solution of table salt (NaCl) is used to convert from EC to ppm): 1 EC = 500 ppm.
European standard (potassium chloride solution (KCl)): 1 EC = 640 ppm.
Australian standard (the average EC of three salts solution (sodium sulfate, sodium bicarbonate, and sodium chloride), taken in a ratio of 40, 40, and 20): 1 EC = 700 ppm.
How to measure EC levels and interpret EC readings?
The simplest and most common method to take measurements with EC meters is to place them into the nutrient tank for a few minutes.
Note how long the value on the screen does not change. The longer it does not change, the more accurate results you get. Check your EC readings at least once per day, however, the best thing is to check them a few times a day to notice changes in time.
If the level is high, it means there is too much mineral salt in a nutrient solution, in this case, you should dilute it by adding more water. Stir up the solution to stabilize the reading and check it again.
If the level is low, it means there is too little mineral salt resulting in nutrient deficiencies. For this, you need to add nutrient concentrate.
Please note that you need to check the EC before adding anything to it to know exactly the current EC.
Maintenance
Having figured out how to use EC meters, it is worth mentioning how to take care of the device itself. Needless to say, misuse and careless handling of the meter leads to its breakage forcing you to spend money on a new device.
Therefore, the first thing you need to bear in mind is that constant use of the meter causes salts to build up on the meter.
That is why teach yourself to clean the meter after every use to extend the life of the device and get accurate readings.
Also, do not forget that all meters that measure nutrient solutions should be stored in a cool place. Avoid placing them in high temperatures or direct sunlight, as it will shorten the lifespan of your meter.
Frequently asked questions
What should the EC be for hydroponics?
What happens if EC is too high?
What’s the difference between EC and pH?
The power of hydrogen or pH indicates the acidity of the substrate. The more active the H+ ions, the more acidic the nutrient soliton. Usually, plants grow well between the pH range of 5.5–6.5, but if the range goes outside these numbers, the plants won’t be able to get some nutrients, resulting in nutrient deficiencies.
EC, on the other hand, shows the total concentration of dissolved salts and mineralization level in a nutrient solution. EC requirements change as the plants grow from a seedling into a mature plants.
Conclusion
Growing a hydroponic plant is not as complicated as it may seem at first glance. The main thing you need to keep track of is nutrient level in liquid nutrient solutions. The most convenient way to do it is to use an EC meter that will let you monitor the health of your plants and adjust the EC level when required.
As long as you can keep the EC level on the right side, your plants will be able to grow to their full potential.
