The definition of hydroponics — the growing of plants, using mineral nutrients, without soil — underscores the importance of nutrients within hydroponic systems.
But the real value of nutrients in the hydroponic system is better defined by using the phrase, “using only fully available mineral nutrients.”
For example, the highly important element phosphorus may be present in soils, but it is held, or “fixed” to soil particles so tightly, that it is often not available for absorption by the plant’s root system.
In the case of Nitrogen (N), if microbial colonies that are required to convert organic forms of nitrogen to plant available inorganic forms are absent or limited in size, the availability, type and concentration of this important element can be limited.
In hydroponic systems, growers are able to control not only the type and concentration of nutrients but also their availability. Nutrients are applied directly to the plant root system. This results in significant energy savings since the plant does not have to use its energy to support photosynthesis and other reactions and processes required to build extensive root systems required by plants grown in soils.
This energy savings often results in improved whole plant growth, development and yield compared to soil grown systems. Root systems of hydroponic plants are also routinely healthier and more efficient and root systems of plants grown in soils.