Many home gardeners know the importance of plant food. Regular applications of fertilizer go a long way towards improving the health of a plant. What these home gardeners may not realize is that they are not providing actual "food" to the plant, according to Clemson University. Rather, fertilizer provides the nutrients and minerals needed for the plant to create its own food. The effect of plant "food," then, is to help the plant photosynthesize effectively.
There are two broad types of plant food. One is plant food that has a quick effect on plants. These foods are usually liquid in form and are used once every two weeks in place of a regular watering, according to the University of Illinois. The other type of fertilizer is called "slow-release." This type is water-soluble and enclosed in a resin that allows it to slowly disintegrate when it comes in contact with water. Each time you water, a little bit of the fertilizer is released. The effect on the plant is gradual over time.
Plant food contains macro- and micronutrients. Ideally, these nutrients grow naturally in the soil, but in reality, many soils are poor in some of these minerals and nutrients. Plants need nine macronutrients in fairly large amounts to grow well, according to Ohio State University. These are nitrogen, potassium, magnesium, oxygen, hydrogen, phosphorus, calcium, sulfur and carbon. The seven micronutrients are copper, iron, chlorine, manganese, molybdenum, boron and zinc.
Plant food, or fertilizer, replaces the nutrients and minerals that are either lacking in poor soils, or leach out of the soil due to watering practices. Container plants, for example, tend to lose nutrients rapidly. The effect of plant food is to immediately replace those nutrients, so that the plant does not start to suffer the ill effects of reduced nutrition.
Different minerals and nutrients have different effects on the plant. The primary ingredients in most fertilizers are nitrogen, phosphorus and potassium, according to Clemson University. Nitrogen encourages the growth of new foliage and shoots. Phosphorus helps plants produce blooms. Potassium works to help the plant produce and move the food throughout the plant. Micronutrients are also important. Iron, for example, is an important factor in the formation of chlorophyll.
The minerals and nutrients in fertilizers work together to improve the overall health of the plant. This includes easily seen effects such as increased shoot growth, increased blooming and more prolific fruiting. The plant may appear fuller, and it might even have brighter-colored flowers, according to the University of Florida. In addition, fertilizer helps newly planted shrubs, trees and perennials establish themselves, and it can help correct nutritional deficiencies in plants that are suffering from a lack of certain minerals.