How to measure hydroponic nutrient solutions?

You may be wondering by now how you go about measuring the concentration of nutrient solution you are using for your hydroponic vegetable gardening. The concentration of nutrients in the solution is typically measured by the electrical conductivity of the dissolved minerals in the water. The measurements results are in parts per million (ppm). The drawback to this method is that it only measures the total conductivity of the solution, not the concentrations of the components in the solutions. This is why the solutions are sold in concentrated mixes of multiple parts instead of individual chemicals. Once you have the mixes adjusted correctly, its easy to add water to dilute the solution to achieve the correct conductivity that you’re after.
It is also important to measure the pH of the nutrient solution. Too base, ie the pH is too high, and you’ll burn the plants possibly even killing them. Too acidic, ie the pH is too low, and you also run the risk of killing the plants. The ideal pH of the nutrient solution should be between 5.5 and 6.5 for optimal plant uptake. pH can be adjusted downwards using a pH lowering solution, or even lemon juice in a pinch. pH can be adjusted upwards using a pH raising solution or sodium bicarbonate in a pinch. Neither of these solutions will be as good as a store bought chemical for adjusting the pH.

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