All plants need access to the right amount of food (nutrients) so that they can grow and thrive. Over- or under-feeding your plants can result in the waste of expensive nutrient resources.
The easiest way to keep track of the amount of nutrients in your solution is to regularly measure conductivity, which refers to the total ionic content (dissolved salts) in a solution. From a scientific perspective, when nutrients are added, this creates the potential for electricity to move through a solution, increasing the electrical conductivity.
Measuring the temperature of your solution is equally important, as - if it’s too hot or too cold - this can affect the plants’ growth rate and structure.