One fact about fertilizer is that it provides plants with nutrients, mainly nitrogen, phosphorus and potassium, which are essential to their growth and development. Another fact is that fertilizer enhances the water-retention and aeration capabilities of soil.
Fertilizer contains additives that increase plant growth. The main ingredients in fertilizer each provide functional benefits to aid plant development.
Nitrogen is necessary for leaf growth and supplies plants with the proteins needed to create tissues. Nitrogen is abundant in the atmosphere, but exists in a form that plants can not use. Fertilizer is necessary to give plants the nitrogen they need.
Phosphorus helps plants grow roots and increases seed size. It aids plants in energy transfer and gives them a head-start when it is time to produce flowers and fruit.
Potassium strengthens the stems of plants which helps with transporting water. This nutrient also improves disease resistance, helps plants make carbohydrates and regulates metabolic activities within plants.
Soil often lacks the necessary ingredients and properties that plants need in order to thrive. This effect is amplified in soil that has been used before. Plants absorb nutrients from the soil and leave it less fertile with each use. Fertilizer replaces the nutrients in soil and helps it retain moisture.
Too much fertilizer is detrimental and causes fertilizer burn due to the high concentration of nitrogen. The low amount of usable nitrogen available to plants caused them to develop a tendency to absorb as much nitrogen as possible. Plants even do this at the expense of other nutrients, so avoiding over-fertilization is mandatory to maintain plant health.