Essential nutrients are a vital component of a plant's survival. While plants are able to obtain some nutritional elements, such as hydrogen and oxygen, naturally through the air and water, the three major macronutrients are typically supplied through commercial fertilizers. In order to qualify as complete, a fertilizer needs to contain potassium, phosphorus and nitrogen.
Nitrogen, a crucial part of a plant's survival, is an essential nutrient and is always the first element listed on a commercial fertilizer's label. All living cells contain nitrogen. While a plant is able to obtain a minimal amount of nitrogen from the air, a commercial fertilizer serves to supplement the supply, according to the North Carolina Department of Agriculture. Nitrogen works to promote proper leaf and stem growth, as well as the production of both seeds and fruit. Nitrogen also plays a crucial role in the production of chlorophyll, which creates the green coloring in both plants and lawn. While nitrogen is one of the most important elements, it is also the one that diminishes mostly quickly, particularly in grass. Fertilizers that supply a slow release of nitrogen are typically best for plants, as they discourage burning and work for a longer time period. Although nitrogen is important, too much of this element can actually be detrimental to plants and lawns.
With the exception of nitrogen, potassium is the element that is absorbed in the largest amount. Plants are unable to obtain potassium through the air and water, so they rely on either soil or fertilizers to get this nutrient. Potassium is particularly helpful in the early growing stages, as it helps to create green, healthy foliage. Potassium increases the overall hardiness of plants, as well as helping to prevent disease and stress, according to McDonnell Nursery. Potassium promotes photosynthesis and aids in proper fruit production and quality. Potassium is necessary in preparing plants for colder weather, as it helps to make a plant stronger for the winter months. Potassium contains a high level of salt; applying too much can result in burning of both plant leaves and grass and can also lead to diminished production of both flowers and fruit.
A plant is unable to obtain phosphorus through the air or water. Instead, it relies on fertilizers in the soil in order to access this important nutrient. Phosphorus is best applied before planting begins or during the actual planting process itself, as it creates a strong root system in developing plants. It also helps to ensure proper growth during the plant's maturation period. Phosphorus, also known as the bloom booster in liquid fertilizers, helps in the creation of blooms as well as fruit, according to donnan.com. Phosphorus aids in the production of both starch and proteins within a plant, as well as promoting the synthesis of proteins. When used in the fall, fertilizers with phosphorus help to ensure prolific blooming in the spring. Phosphorus is also a crucial part of photosynthesis and serves to promote rapid growth within a plant.