In the previous article, we discussed the types of hydroponic systems, various state governments, and central government schemes and brief SWOT analysis of this enterprise. In this article, I am going to share and discuss some information regarding the TDS and pH of the nutrient solution present in your selected type of system, how relevant it is to know about this, and what can happen if you ignore or underestimate the power of TDS and pH.
What is TDS and why it is important?
TDS stands for Total Dissolved Solids, this term is used to determine the inorganic salts (magnesium, potassium, bicarbonates, chlorides, sodium) along with a small amount of organic matter present in the solution in water.
In terms of hydroponics, TDS is a measure of the nutrients in the solution, low TDS means that there is a low nutrient concentration that can result in nutritional deficiencies and slow growth rate of the plants – although one should be cautious of high levels of concentration that can burn or kill the plant.
High levels of TDS means more dissolved salts in the solution. The delicate plants, cuttings and seedlings can experience fertilizer burn if TDS is too high. Plants require more nutrients when they enter the growing phase, so during this phase, TDS can be increased by adding concentrated nutrients. As different plants require different nutrient concentration, one should have some knowledge about it that can help the plant grow better.
How to measure TDS?
TDS in a nutrient solution can be measured with the help of a TDS meter, quite easily available on e-commerce websites from a range of INR 150 to INR 400. If your plant nutrient recommendations are in ppm, I would suggest you go with a sodium chloride TDS calibration that is easier to use.
What is pH and why it is important?
pH stands for potential of hydrogen, it helps in determining the concentration of hydrogen ions in a solution and it indicates the acidity or basicity of a solution.
The pH plays a very important role in hydroponics or regular soil gardening, if pH is not at a proper level the plants lose its ability to absorb some of the essential elements required for healthy growth.
Different plants have different and specific pH levels that result in optimum yields. Although the pH level might vary from one plant to another, generally most plants have a pH range of 5.5 to 6.5.
What happens when pH rises?
When the pH rises say above 6.5, then the precipitation of nutrients and micro-nutrients present in the solution begins and can stick to the walls of the reservoir and growing chambers. Once the nutrients precipitate out of the solution then the plants can no longer absorb them and that would lead to deficiency and eventually, the plant would die. If you don’t pay attention, sometimes the precipitation of nutrients also occur when pH is low, hence proper balance of pH is required for healthy and optimal growth.
How to measure pH?
Various pH meters are available on different e-commerce websites ranging from INR 500 to INR 1000 – pH meters are quite temperature-sensitive and get damaged without giving any warnings. I would suggest keeping an extra pair, just in case the primary meter gets damaged.
Like any measuring instrument, this also needs to be calibrated before using it.
The paper test strips are also available and are an inexpensive alternative to check the pH of the nutrient.
Why stress on TDS and pH?
As a beginner in hydroponics you would have brought or built a system. Usually when you buy a system there is a manual that guides you and tells you the required nutrient concentration, so you need not waste your time in brainstorming – the recipe is right there. You can start your venture but if you don’t pay heed to the TDS and pH levels, the only thing that would grow will be a disappointment and not plants. I made the same mistake, but I believe failure is an opportunity for you to learn more so that you can work on your errors and try to keep the count low. Below is a list of some plants with their respective pH and TDS levels.
PLANTS | pH | TDS (in ppm) |
Strawberries | 5.5-6.5 | 1260-1540 |
Pineapple | 5.5-6.0 | 1400-1680 |
Cabbage | 6.5-7.0 | 1750-2100 |
Onions | 6.0-6.7 | 980-1260 |
Garlic | 6.0 | 900-1260 |
Carrots | 6.3 | 1120-1400 |
Capsicum | 6.0-6.5 | 1260-1540 |
Spinach | 5.5-6.6 | 1260-1610 |
Sweet Potato | 5.5-6.0 | 1400-1750 |
Basil | 5.5-6.5 | 700-1120 |
Roses | 5.5-6.0 | 1050-1750 |
Potato | 5.0-6.0 | 1400-1750 |
So now you can select one plant of the same pH and TDS levels or different plants that have the same pH and TDS level – the choice is yours.
So let’s farm from home and save the Earth by adding to the economy!