EC and TDS in Hydroponics

In hydroponics, managing nutrient concentrations is very important in plant growth and production. Electrical Conductivity (EC) and Total Dissolved Solids (TDS) are two essential parameters for monitoring nutrient solutions. 

EC measures a solution’s ability to conduct electricity which is directly related to the concentration of dissolved ions, including nutrients like nitrogen, potassium, and magnesium. It is expressed in millisiemens per centimeter (mS/cm) or microsiemens per centimeter (μS/cm). A higher electrical conductivity (EC) signifies a greater presence of dissolved salts or nutrients.

On the other hand, TDS estimates the total concentration of dissolved solids in the solution, including organic and inorganic substances, and is measured in parts per million (ppm). TDS is derived from EC using a conversion factor that depends on the nutrient composition of the solution. The close relationship makes both EC and TDS valuable for assessing nutrient levels, though EC is often preferred for precision.

EC and TDS are widely used in hydroponics for nutrient monitoring, water quality assessment, and precision feeding. Maintaining appropriate EC and TDS levels ensures plants receive adequate nutrients, avoiding deficiencies or toxicities. 

For instance, low EC indicates insufficient nutrient concentration, while high EC can lead to osmotic stress or nutrient toxicity, which can harm plants. TDS, while less precise, is useful for evaluating water purity. High TDS in source water may indicate the presence of contaminants or unwanted minerals that could impact plant health. 

By regularly monitoring these parameters, growers can make necessary adjustments to meet the plants’ requirements at various growth stages. Seedlings, for example, require lower EC/TDS to prevent stress, while vegetative and flowering stages demand higher levels to support robust growth and maximize yield. Both EC and TDS also help detect issues like nutrient imbalances or salt buildup.

Despite their utility, there are challenges associated with using EC and TDS. EC does not differentiate between beneficial nutrients and harmful salts, so additional water testing may be required to identify contaminants. Nevertheless, EC and TDS are essential tools for hydroponic growers. They help manage nutrients precisely, solve problems, and improve the system’s performance. By regularly checking these measurements, growers can ensure that plants get the nutrients they need at each growth stage. This practice leads to healthier crops and better yields in hydroponic systems.

References:

Jamil, A., Ting, T. S., Abidin, Z. Z., Othman, M., Wahab, M. H. A., Abdullah, M. F. L., Homam, M. J., Audah, L. H. M., & Shah, S. M. (2023). Polynomial Regression Calibration Method of total dissolved solids sensor for hydroponic systems. Pertanika Journal of Science & Technology, 31(6), 2769–2782. https://doi.org/10.47836/pjst.31.6.08 

Yolanda, D., Arief, L., Sundara, T. A., Deza, M., & Oktavia, D. (2018). Control of electrical conductivity for NFT hydroponic systems using fuzzy logic and Android Environment. 2018 International Conference on Information Technology Systems and Innovation (ICITSI). https://doi.org/10.1109/icitsi.2018.8695923

Ouyang, Z., Tian, J., Yan, X., & Shen, H. (2019b). Effects of different concentrations of dissolved oxygen or temperatures on the growth, photosynthesis, yield and quality of lettuce. Agricultural Water Management, 228, 105896.