Plant Nutrition

Plant Nutrition

          Plants need 17 elements for normal growth. Carbon, hydrogen, and oxygen are found in air and water. Nitrogen, potassium, magnesium, calcium, phosphorous, and sulfur are found in the soil. These six elements are used in relatively large amounts by the plant and are called macronutrients. There are eight other elements that are used in much smaller amounts and are called micronutrients, or trace elements. The micronutrients, which are found in the soil, are iron, zinc, molybdenum, manganese, boron, copper, cobalt, and chlorine. All 17 elements, both macronutrients and micronutrients, are essential for plant growth.

Macronutrients	Deficiencies	Remarks
Nitrogen (N) - Part of proteins, enzymes, chlorophyll, and growth regulators.	Reduced growth, yellowing (chlorosis), reds and purples may intensify with some plants, reduced lateral breaks.	Excess will yield all leaf and stem growth, with little fruit.
Phosphorus (P) - Role in fat, carbon, hydrogen, and oxygen metabolism; respiration and photosynthesis.	Reduced growth, color may intensify, foliage turning brown or purple in some plants; thin stems, loss of lower leaves, reduced flowering.	In very acid or alkaline soils, phosphorus will be unavailable.
Potassium (K) - Important in starch formation, sugar translocation, water relations, disease resistance, chlorophyll development, and tuber formation.	Reduced growth, shortened internodes, marginal burn or brown leaf edges, dead spots in the leaf, reduction of lateral breaks, and tendency to wilt readily.	Large amounts of potash are needed by most plants.
Magnesium (Mg) - Part of chlorophyll, enzyme activator; important in energy utilization.	Reduction in growth; yellowing between veins, also can occur with middle or lower leaves; reduction in seed production.	Interferes with calcium uptake if used in excess.
Calcium (Ca) - Important in cell wall structure, cell division, enzymes, and as an enzyme activator.	Inhibition of bud growth, death of root tips, cupping of mature leaves, weak growth.	Too much calcium will result in high pH, causing many of the micronutrients to become unavailable to the plant.
Sulfur (S) - Part of protein, amino acids, vitamins; important in respiration.	Symptoms are a general yellowing of the affected leaves of the entire plant.	In Virginia, acid rain discharges 10 pounds of sulfur per acre to the soil each year.

            When you're providing those extra nutrients for your plants, be sure to measure fertilizers accurately and apply them safely. Fertilizer run-off ends up in nearby streams and ultimately upsets the water quality in your community.