If you’re getting into hydroponics, you’ll quickly come across two terms that are crucial to the success of your plants: pH and EC. But what do these values actually mean, and why are they so important? In this article, you’ll learn everything you need to know to help your plants grow healthy and strong.
What is pH?
The pH value indicates how acidic or basic a solution is. In hydroponics, pH is essential because it affects nutrient availability for your plants. A pH of 7 is considered neutral, values below 7 are acidic, and values above are basic.¹
For most hydroponic plants, the optimal pH range is between 5.5 and 6.5. Within this range, roots can best absorb nutrients such as nitrogen, phosphorus, and potassium. If the pH is too high or too low, nutrient deficiencies can occur, even if nutrients are present in the water.
What is EC?
EC stands for “Electrical Conductivity” and measures how well a solution conducts electricity. In hydroponics, the EC value indicates the amount of nutrient salts dissolved in your nutrient solution. The higher the EC, the more nutrients are available – but be careful: too high levels can harm your plants!
An optimal EC value varies by plant species but often falls between 1.2 and 2.5 mS/cm (millisiemens per centimeter). A low EC level indicates nutrient deficiency, while a high EC can lead to salt stress, which can hinder plant growth.
TDS and PPM – Other Important Measurements
Besides pH and EC, there are other units you should know about. TDS (Total Dissolved Solids) and PPM (Parts Per Million) are two of them. TDS indicates how many solid substances are dissolved in a solution, while PPM indicates the concentration of these substances in the solution. Both values are often used to assess nutrient solution quality.
Generally, an EC value of 1 mS/cm corresponds to about 500-700 PPM, depending on the conversion formula used. This information can be helpful if you want to adjust your nutrient solution precisely.
Using Measuring Devices
To accurately measure EC and pH values, you need a reliable and easy-to-use measuring device. When choosing an EC meter, it’s important to select one with temperature compensation, as the temperature of the nutrient solution affects electrical conductivity, and without this feature, you might get inaccurate readings.
Measurement itself is simple: dip the EC meter into the nutrient solution and read the displayed value. Most modern devices show the EC in μS/cm (microsiemens per centimeter). To convert this to mS/cm, simply divide the value by 1000.
Remember to rinse your device with clean water before and after each measurement to remove residues that could distort future readings. This also applies to pH meters, which are often stored in special solutions to maintain accuracy.
Correctly Interpreting EC and pH Values
When you mix your nutrient solution and check the EC and pH values, it’s essential to draw the right conclusions from them. The EC value gives you a general idea of the amount of dissolved nutrients but says nothing about their exact composition. An EC of 1000 μS/cm achieved by adding table salt would be harmful to your plants, even though the value itself might seem acceptable.
Therefore, it’s essential to know the nutrient solution composition and ensure all key nutrients are present in the right proportions. We recommend using fertilizers specifically formulated for hydroponics, which already contain the optimal mix ratio. Also, avoid simply topping up the nutrient solution too frequently; instead, change it out regularly. Otherwise, you may create an imbalance, as some nutrients are consumed faster than others by the plants, while others accumulate in the water. This imbalance can lead to nutrient deficiencies or excesses, which can affect plant growth.
The Right Balance for Healthy Plant Growth
Controlling pH and EC values is essential for the success of your hydroponic plant growth. With the right measuring tools and a bit of practice, you’ll quickly learn how to optimize these values for the best possible growth and harvest.
Remember to measure regularly and record the results to develop a better understanding of your plants’ needs over time. This way, you can ensure that your plants always grow under the best conditions and enjoy a bountiful harvest.
