Plants require food for survival, just like all other living organisms. Plant roots pull nutrients from the soil for survival and reproduction. Soil loses elements over time due to watering, soil pollution and plants using up the resources. Adding plant food enriches soil with life-giving nutrients for plants.
Plant food labels display three numbers, separated by a hyphen. The numbers indicate the amount of nitrogen, phosphorous and potassium nutrients within the mixture based on percentages. For example, a plant food labeled 10-20-10 has 10 parts nitrogen, 20 parts phosphorous and 10 parts potassium nutrients. Plant food containers typically specify what types of plants need the food. For example, a label may read "vegetable plant food" or "plant food for roses."
The primary function of plant food is to provide soil nutrients to plants. Plant food replaces leeched soil nutrients. Plants require larger amounts of nitrogen to grow quickly and produce a large abundance of leaves, such as vegetables or fast growing evergreens. Flowering or blooming plants that grow at a slow to average pace require phosphorous and potassium, such as roses or perennial flowers.
Timing is important when utilizing plant food. Plants need more plant food during the spring and summer months while growing, producing flowers, forming seeds and yielding fruit. Trees, many evergreens and perennials often become dormant during the late summer, fall and winter months. During the dormancy periods, there is less demand for plant food. Often, gardeners can skip adding plant food to soil during the dormancy period.
Plant food is available in different types of medium. Concentrated plant food requires adding water to dilute to the right formula. Plant food stakes insert into the ground near plants and dissolve slowly. Time-released granule plant food mixes in with the soil and dissolves a little at a time with each watering.
Organic plant food comprises of all natural or organic ingredients. Many growers use homemade recipes to create different types of plant food that cause the least effect on the environment.
Novice gardeners have the misconception that more is better when it comes to plant food applications. It is best to underfeed plants because too much plant food can cause damage to leaves, stems, branches and even flowers or fruit.
Always avoid pouring liquid plant food directly onto roots or foliage. Direct exposure burns plants, or even kills them.