What is water-soluble fertilizer?

It contains all the nutrients plants need to grow. These nutrients come in different sizes. The larger ones are called macronutrients, such as nitrogen, phosphorus, and potassium. The smaller ones are called secondary and micronutrients, such as calcium, magnesium, sulfur, iron, manganese, zinc, copper, boron, molybdenum, and so on. In the fertilizer solution, many of these nutrients are converted into tiny particles (ions). Plant roots can directly absorb these small particles and utilize them. This is important because absorption is rapid.
Take nitrogen as an example. Nitrogen is a nutrient that plants require in large quantities. It serves as the building block for many vital components within the plant, such as proteins and nucleic acids. The nitrogen in water-soluble fertilizers may be in the form of ammonium nitrogen or nitrate nitrogen. Both forms can be rapidly absorbed by plants. Therefore, when plants have an urgent need for nitrogen, water-soluble fertilizers can provide an immediate solution.