Like other forms of life, plants require certain nutrients to survive and grow. While many of these nutrients exist naturally in various types of soils, adding these in the form of fertilizers ensures adequate amounts for quality growth. Fertilization requirements depend on the types of plants you grow, as well as the existing soil composition. Proper fertilization provides missing nutrients in poor soils and also enriches and replaces nutrients in depleted soils, creating a healthy environment for continued growth.
Thirteen mineral nutrients come from the soil. Plants draw these nutrients into their tissues through root systems. Commercial fertilizers often contain varying amounts of the primary nutrients. Plants use large amounts of nitrogen (N), phosphorus (P) and potassium (K), often depleting the soil of these nutrients. Nitrogen helps your plants produce leafy, vegetative growth, while phosphorus encourages strong roots and potassium helps your plants stand up to stress. Potassium also stimulates flower color. Fertilizers help to replace these primary nutrients, encouraging continued growth.
Plants also require non-mineral nutrients, such as hydrogen (H), oxygen (O) and carbon (C). While fertilizers cannot provide these natural elements, supplying adequate amounts of mineral nutrients helps strengthen your plants, encouraging them to turn non-mineral nutrients into energy, a process known as photosynthesis.
Soil types vary, depending on a variety of conditions. The texture of your soil, as well as its pH level, helps to determine how well your plants grow. A soil test gives you accurate information regarding the existing health of your soil. Test results also recommend soil additives and fertilizers to help with plant growth.
Fertilizers also help to adjust the pH level of your garden soil. While some plants thrive in alkaline soils, others require acidic mediums to survive. Lime lessens soil acidity and supplies magnesium and calcium. Sulfur helps to lower the alkalinity of soil and encourages healthy growth and plant metabolism. Adjusting the pH level of your soil with fertilizers helps plants develop strong stems, abundant leaves and quality fruits.
The type and timing of your fertilization depends on your soil, growing season and choice of plants. Applying a basic fertilizer during planting encourages sprouting and early establishment. Adding a nitrogen fertilizer when plants begin forming new stems, branches and leaves promotes abundant foliage. Applying a potassium fertilizer when flower buds begin forming encourages abundant blossoms and subsequent fruits.