Plants need a wide range of elements to grow; fertilizer provides them. Over time, soil loses many of these elements, and fertilizer ensures that soil can support plant growth. Fertilizer is especially useful in farming, where efficiency is important.
Plants get many of the elements they need through the air. Oxygen, carbon and hydrogen are readily available. In addition, plants can create glucose and other substances through sunlight. However, basic elements cannot be created through photosynthesis, and plants must extract these elements through the soil.
Even though air contains a significant amount of nitrogen, plants cannot absorb it. As a result, they must get it from the soil. Nitrogen becomes depleted in soil quickly, and the primary benefit of fertilizer is the nitrogen it provides. Plant cells also depend on potassium and phosphorous, which are rare. Fertilizer contains a large amount of these elements, which ensures that plants stay healthy.
Plants can generally grow without fertilizer, but they may take more time to get the elements they need to thrive. Fertilizer is essential in modern farming, and almost all farmers depend on it to keep their fields healthy and productive. Gardeners often use small amounts of fertilizer as well to ensure that their flowers and other plants look their best.