Nitrogen

• Nitrogen is an important growth factor for plants and promotes the growth of seeds, fruit, leaves and overall hardiness. Fertilizers with nitrogen are designed to increase the size and growth rate of the plant. This mineral is also a key component in chlorophyll, a chemical required for photosynthesis. Plants that do not have enough nitrogen grow slowly and have discolored foliage. Low-lying leaves that appear burnt or singed at the edges are an early sign of nitrogen deficiency.
  
  

Phosphorus

• Phosphorus is an important nutrient that is used in photosynthesis and other chemical processes of plants. It promotes early growth and ensures healthy growth throughout the life cycle of a plant. This nutrient is also beneficial for early or late plantings since it increases the ability of plants to withstand low temperatures. Plants that do not have enough phosphorus grow slowly and have darkened leaves with a leathery texture. Deficient plants will have leaves with a reddish tinge at the leaf tips. Low temperatures can inhibit the ability of plants to absorb phosphorus, resulting in poor growth.
  
  

Potassium

• Potassium is an important nutrient that contributes to a variety of chemical processes in plants. Potassium promotes the sturdiness of stems and stalks and provides increased drought- and disease-resistance. This nutrient also affects the quality of the fruit and seeds your plants produce and their ability to flower. Potassium deficiency causes physical weakness in plants, typified by weak stems and chlorosis. Yellowed leaves and stems on the lower parts of the plant are often caused by a lack of potassium.
  
  

Other Minerals

• Potassium, phosphorus and nitrogen are the three major nutrients that plants require for healthy growth. However, they also require minerals, including copper, sulfur, zinc, iron, manganese, magnesium and calcium. Most soil types provide these nutrients in sufficient quantities without fertilization since most plants only require small quantities of each mineral. In areas with poor soil, including clay or sandy soil, a test can accurately determine if your soil is deficient in these minerals.