Type of Fertilizers

• Phosphorus, an element necessary for plant growth and normal root development, is a common ingredient in seed coatings. Other macronutrients required by plants that may be added to seed coatings are nitrogen, potassium and sulfur. Micronutrients, elements required by plants in very small amounts, such as zinc, iron and molybdenum, are also part of seed coating materials.
  
  

Type of Seeds

• Many types of seeds are successfully coated with fertilizer. Legume seeds such as alfalfa and clovers, grass seeds, wildflower seeds, cereal grains, oil crop seeds and vegetable seeds are available with fertilizer coatings. Commonly coated vegetable seeds include muskmelon, beets, corn, cucumber and watermelon.
  
  

Other Types of Coatings

• Often other materials are added to a seed coating along with fertilizer. Legumes can obtain nitrogen from the air due to a relationship between the legume plants and Rhizobium bacteria. Seed coatings may contain Rhizobium bacteria to preinoculate legume seeds. Seed coatings often contain lime, a substance useful to plants in acidic soil. Pesticides and fungicides may be added to the coating to control plant diseases.
  
  

Benefits of Seed Coatings

• Coated seeds may protect the germinating seeds from stressful environmental conditions such as drought. Coated seeds are heavier, and this may improve germination after aerial planting. Birds and rodents may not recognize coated seeds as food and may resist the bad taste of the coating. Coated seeds may be easier to plant and often remain viable longer than uncoated seeds when stored.