by: Charlene Rennick
Once you start a hydroponic system, regardless of the type you choose, you will need to check the nutrient and pH level of the solution. Even with a passive, non-recovery type of hydroponics, you will need a basic knowledge of how to create a healthy, nutrient-rich liquid.
The roots of the plants absorb their value from the solution as they need it, so the nutrients will have to be topped up to maintain an optimal concentration for growth. Remember, the plant absorbs water according to the principle of osmosis, so as the nutrient concentration changes, so does the plant’s natural tendency to absorb them. If your nutrient concentration is weak, the plant won’t be inclined to soak up what they need.
How do you measure this? Fortunately, you can purchase a simple device that will perform this service for you. An instrument called a Digital ppm meter can be used to measure the nutrient concentration. A ppm meter measures parts per million (ppm) of the total dissolved solids (TDS). This process is also known as measuring the electrical conductivity of the nutrient-rich water. The digital meters have to be calibrated every so often in order to keep them accurate. This is done by placing the meter in a solution that has an established parts per million of total dissolved solids.
Another important reading to take is the pH level. Experts in hydroponic gardening recommend taking the ppm measure first, followed by adding the nutrients and waiting a couple of hours. Then when the pH level is measured, the nutrients will be dissolved properly which will give you the most accurate reading of the pH level. Pure water has a pH level of 7 which is considered the mid-point of the ph scale. A reading of 1 is the most acidic and a reading of 14 is the most alkaline.
Adjustments to the pH level should be made with caution! Acid and alkaline concentrates are very powerful so it is recommended to mix up these ahead of time in an empty gallon container to let settle. Practise adding a few drops at a time to water to determine how many drops will cause an effect on the pH reading. Better to experiment in a cup of water than to ruin your more expensive nutrient-rich solution.
If you are just beginning your hydroponic journey and want to keep your equipment at a minimum, changing the nutrient solution every two weeks is a good way of intuitively tending your hydroponic garden.