A hydroponic growing system is designed so that plants grow in water with or without soilless growing media. Plants in soil can get the nutrients they need from the soil. Plants in a hydroponic system have to get the nutrients they need from water. Nutrient solutions contain elements that plants need to grow, bloom and produce fruit. The solution is mixed with the water and replaced as the plants absorb the nutrients. The essential nutrients for plants are divided into primary macronutrients, secondary macronutrients and micronutrients.
Nitrogen, phosphorous and potassium are the primary macronutrients. Nitrogen aids in the synthesis of protein and the development of new leaves. Phosphorous is essential to photosynthesis, root growth, blooming and fruiting. Potassium is used in the formation of sugars and starches, and it strengthens the plant's resistance to diseases and environmental stresses.
Calcium, magnesium and sulfur are the secondary macronutrients. Calcium aids in cell growth and division to produce new roots and shoots. Magnesium is used in photosynthesis and is a part of chlorophyll. Sulfur is used in the production of amino acids, proteins and glucose. Calcium helps the plant absorb potassium, while magnesium and sulfur help with the absorption of phosphorous.
Nutrient solutions may contain up to 11 micronutrients. Copper, iron, manganese and molybdenum are elements of chlorophyll. Cobalt fixes nitrogen in the plant, while nickel releases nitrogen from the plant. Chlorine aids in root growth, silicon strengthens cell walls and sodium is used in the transport of water. Boron is vital to reproduction, while zinc helps with essential functions.